Exhibit 2

31 December 2015

THE INSTITUTIONAL SELLERS

APPLEBY TRUST (JERSEY) LIMITED

THE MANAGEMENT SELLERS

WHITEWELL UK INVESTMENTS 1 LIMITED

ACADIA HEALTHCARE COMPANY, INC.

SALE AND PURCHASE DEED

relating to the entire issued share capital of Priory Group

No. 1 Limited

Freshfields Bruckhaus Deringer LLP

65 Fleet Street

London EC4Y 1HS

CONTENTS

Agreed Form Documents

Allocation Table

Data Room index

Deed of termination in respect of the Investment Documents

Pro forma director resignation letter

Pro forma indemnity in respect of lost share certificates

Certificates of title

Press announcement

Agreed Threshold Share Price document

THIS DEED is made on 31 December 2015

PARTIES:

(together, the parties ).

Words and expressions used, and not otherwise defined, in this Deed shall be interpreted in accordance with Schedule 9.

IT IS AGREED:

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in each case free from all Third Party Rights and with all relevant rights then attaching to them including the right to receive all distributions and dividends declared, paid or made after Closing and all distributions and dividends on the Preference Shares accrued or declared, but unpaid, prior to Closing.

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If the Public Equity Offering Price is less than the Agreed Threshold Share Price and the Election Notice is not so delivered in accordance with this clause 2.6 making the statement in either paragraph (a) or (b) above in accordance with this clause 2.6, then, in either such case, the Purchaser shall be deemed to have made the Full Top-Up Election. The time of the delivery of the Non Top-Up Election shall be the Notification Time . (Clause 4.8 of this Deed provides for the conduct of communications between the Institutional Sellers’ Pricing Representative and the Purchaser before 16:00 Eastern Standard Time on the Pricing Date.) The Institutional Sellers’ Pricing Representative (on behalf of the Institutional Sellers) may elect within 20 minutes of the Notification Time, by notice in writing (delivered by hand and, to the extent that either or both of the Purchaser Guarantor and the Institutional Sellers’ Representative are available, will simultaneously be notified by conference call) to the Purchaser’s Counsel (acting on behalf of the Purchaser), to terminate this Deed and following any such termination, the parties shall have no rights and liabilities under this Deed, save for any rights and liabilities which have accrued before termination or under any of the Surviving Provisions. A Full Top-Up Election (or a deemed Full Top-Up Election), shall be an irrevocable and binding commitment

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Each Management Seller hereby:

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provided, however, that nothing herein shall require such cooperation to the extent it would: (i) interfere unreasonably with the Business or operations of any of the Target Companies; (ii) require any Target Company to take any action that would conflict with or violate any such Target Company’s constitutional documents, material agreements or any laws; (iii) require any Target Company to enter into or approve any agreement referred to in this clause 4.1(b) prior to Closing or that becomes effective prior to Closing (except customary representation letters required by external auditors of any Target Company); (iv) subject any Seller or Target Company or any of their directors, officers or employees to actual or potential liability, require any of them to bear any cost or expense or to pay any commitment or other similar fee or make any other payment or incur any other liability or require any of them to provide or agree to provide any indemnity, guarantee or pledge in connection with the Purchaser’s Financing or any of the foregoing prior to the Closing or that becomes effective prior to the Closing; or (v) require the provision of any financial statements or financial or other information other than the Required Target Financial Information;

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and any consequential amendments to the allocation of the consideration payable to each Seller for the Shares and to repay the Outstanding Notes Debt, it being agreed that the allocation of the consideration under the Revised Schedule shall adjust the Share Price and the Outstanding Notes Debt and their respective allocations, but in no circumstances result in an increase to the aggregate of the Share Price and the Outstanding Notes Debt payable by the Purchaser (without prejudice to the operation of clauses 2.4 to 2.6). The Purchaser shall not be concerned with, and shall have no liability in respect of, the provisions of the Articles which shall govern the allocation of proceeds among the Sellers in accordance with the terms hereof and thereof.

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provided such action(s) does not prohibit Closing.

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it being understood that the right to terminate this Deed under this clause 5.13 shall not be available to any party who is then in breach of any of its material obligations in Schedule 2 (being those set out in paragraphs 1(a), 1(b)(ii), 1(b)(iii), 1(b)(v) and 1(c) of Part A of Schedule 2 in respect of the Sellers, and those set out in Part B of Schedule 2 in respect of the Purchaser and the Purchaser Guarantor) (and for this purpose the Purchaser shall be treated as in such breach if it or the Purchaser Group is in such breach, and vice versa).

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From the date of this Deed until Closing, the Purchaser Guarantor undertakes to comply with the obligations set out in Schedule 7.

Subject to the rights of termination expressly provided for in clauses 2.6, 5.12 or 5.13(c), no party shall be entitled to rescind or terminate this Deed in any circumstances whatsoever (whether before or after Closing). This shall not exclude any liability for (or remedy in respect of) fraud or fraudulent misrepresentation.

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in each case save as may be required by law or regulation (including any reporting or filing requirements in relation to the continued operation and/or liquidation of any such person) or in connection with any contracts or arrangements that any such person or any of their Affiliates may at any time after Closing enter into with any of the Target Companies or their Affiliates.

for a period of two years after the Closing Date, directly or indirectly, solicit, endeavour to entice away, employ or offer to employ any Executive Management Team Member.

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then, subject to clauses 12.3 and 12.4, the Institutional Sellers shall jointly and severally, following Closing, pay or procure payment in cash to the Purchaser on demand a sum equal to the amount of such Leakage received by, or for the benefit of, any Institutional Seller or any of its Affiliates (as the case may be) on a pound for pound basis.

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then, such Seller shall severally (but not jointly and severally), subject to clauses 12.3 to 12.4, following Closing, pay or procure payment in cash to the Purchaser on demand a sum equal to the amount of such Leakage received by, or for the benefit of, that Seller or any of its Affiliates (as the case may be) on a pound for pound basis.

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and includes written information and information transferred or obtained orally, visually, electronically or by any other means; and

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provided that in either case, where delivery occurs outside Working Hours, notice shall be deemed to have been received at the start of Working Hours on the following Business Day.

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This Deed and the Transaction Documents together set out the whole agreement between the parties in respect of the sale and purchase of the Shares and supersede any prior agreement (whether oral or written) relating to the Proposed Transaction. It is agreed that:

provided that this clause 23 shall not exclude any liability for (or remedy in respect of) fraud or fraudulent misrepresentation. Each party agrees to the terms of this clause 23 on its own behalf and as agent for each of its Connected Persons. For the purpose of this clause 23, Connected Persons means (in relation to a party) the officers, employees, agents and advisers of that party or any of its Affiliates.

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Without affecting any other rights or remedies that they may have, each party acknowledges that a person with rights under this Deed may be irreparably harmed by any breach of its terms and that damages alone may not necessarily be an adequate remedy. Equitable relief (including the remedies of specific performance and injunction) shall be an available remedy for any threatened or actual breach of, and no proof of special damages will be necessary to enforce, the terms of this Deed.

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Each of the provisions of this Deed and the other Transaction Documents are severable. If any such provision is held to be or becomes invalid or unenforceable in any respect under the law of any jurisdiction, it shall have no effect in that respect and the parties shall use all reasonable efforts to replace it in that respect with a valid and enforceable substitute provision the effect of which is as close to its intended effect as possible.

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Schedule 1 Details of the Sellers

Part A Institutional Sellers

Part B Management Sellers

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Schedule 2 Closing arrangements

Part A Seller Obligations

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Part B Purchaser Obligations

At Closing, the Purchaser shall:

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Part C General

All documents and items delivered at Closing pursuant to this Schedule 2 shall be held by the recipient to the order of the person delivering the same until such time as Closing shall be deemed to have taken place. Simultaneously with:

the documents and items delivered in accordance with this Schedule shall cease to be held to the order of the person delivering them and Closing shall be deemed to have taken place.

Part D Sellers’ Undertaking

Each Institutional Seller undertakes that it shall, immediately prior to Closing:

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Schedule 3 Permitted Leakage

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Schedule 4 Voting Power of Attorney

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Each Seller undertakes to indemnify the Purchaser and each of its agents and estates fully against all actions, proceedings, claims, costs, expenses and liabilities of every description arising from the exercise or the purported exercise in good faith of any of the powers conferred by this power of attorney (including any costs incurred in enforcing this indemnity).

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This power of attorney shall be irrevocable and shall terminate upon the Shares being registered in the name of the Purchaser (or, if earlier, the date falling six months following the Closing Date) and is given on the basis that the Purchaser shall use its reasonable endeavours to effect such registration as soon as is reasonably practicable.

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Schedule 5 Deed of Adherence

THIS DEED is made on the              of              201              by [●] (the New Seller ).

This Deed Witnesses as follows:

and any and all conditions and warranties, whether express or implied by law or otherwise, are to the extent legally possible excluded.

Words and expressions defined in the SPA shall bear the same meanings herein.

This Deed shall be governed by and construed in accordance with the laws of England.

DULY DELIVERED as a Deed on the date and year first above written.

[Execution block to be amended to reflect nature of party signing Deed of Adherence ]

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Schedule 6 Additional Purchaser Guarantor warranties

The Purchaser Guarantor hereby warrants to the Sellers that, except as disclosed in: (a) the Purchaser Guarantor Reports (but excluding any risk factor disclosures contained under the heading “Risk Factors” and in any section relating to forward-looking statements to the extent that they are cautionary, predictive or otherwise forward-looking in nature) where the relevance of the information as an exception to (or disclosure for purposes of) a particular representation, warranty or covenant is reasonably apparent on the face of such disclosure; or (b) the disclosure schedule delivered by Purchaser Guarantor to the Sellers concurrently with the execution of this Deed and annexed to this Deed (the Purchaser Guarantor Schedules ) (each section of which qualifies the correspondingly numbered representation, warranty or covenant if specified therein and such other representations, warranties or covenants where its relevance as an exception to (or disclosure for purposes of) such other representation, warranty or covenant is reasonably apparent):

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The execution and delivery of the Deed by each of the Purchaser Guarantor and the Purchaser do not, and the performance by each of the Purchaser Guarantor and the Purchaser of this Deed and the consummation of the transactions contemplated by this Deed will not, require the Purchaser Guarantor or the Purchaser to obtain any material consent, approval, waiver, authorisation, permit, filing, registration or notification from any governmental or regulatory authority, except: (a) for compliance with the applicable requirements, if any, of the CMA (and any similar law enforced by any governmental or regulatory authority regarding pre-acquisition notifications for the purpose of competition reviews); and (b) for compliance with any applicable requirements of the SEC or the NASDAQ Global Select Market.

The Purchaser Guarantor will have at Closing sufficient authorised but unissued shares of Acadia Common Stock to consummate the transactions contemplated by this Deed including the issue of Acadia Common Stock provided for under the terms of this Deed. When issued in accordance with the terms of the Deed, the shares of Acadia Common Stock constituting the Acadia Common Stock Consideration will be duly and validly issued in accordance with all applicable laws, will be fully paid and non-assessable, will be free and clear of all Liens and will not be subject to pre-emptive rights or similar rights of stockholders, except as set forth in and restrictions on transfer arising under securities laws.

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Since December 31, 2014, except as otherwise contemplated by this Deed or as disclosed in the Purchaser Guarantor Reports, the Purchaser Guarantor and its subsidiaries have conducted their businesses, in all material respects, in the ordinary course of business consistent with past practice.

Section 6 of the Purchaser Guarantor Schedules sets forth: (a) all of the material claims, actions, arbitrations, suits or proceedings of any kind whatsoever, at law or in equity (including actions or proceedings seeking injunctive relief), by or before any governmental or regulatory authority or arbitrator pending or, to the knowledge of the Purchaser Guarantor, threatened in writing against the Purchaser Guarantor or any of its subsidiaries or affecting any of their properties or assets; and (b) any litigation that has been settled for more than US$1,000,000 since January 1, 2014 until the date hereof. Except as set forth in the Purchaser Guarantor Reports, neither the Purchaser Guarantor nor any of its subsidiaries is (or has been since January 1, 2014) a party to or subject to, or in default under, any order, decree or judgment of any court or any governmental or regulatory authority ( Orders ) that are material to the Purchaser Guarantor and its subsidiaries, taken as a whole.

Except as would not be material to the Purchaser Guarantor and its subsidiaries taken as a whole, the Purchaser Guarantor and each subsidiary of the Purchaser Guarantor possess all Permits required under applicable laws to own, lease and operate its properties and assets and

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to carry on its business as it is now being conducted (collectively, the Purchaser Guarantor Permits ) and as of the date hereof there is no proceeding by or before any governmental or regulatory authority pending or, to the knowledge of the Purchaser Guarantor, threatened in writing regarding the revocation of any such Purchaser Guarantor Permit or a declaration of any such Purchaser Guarantor Permit as invalid. The Purchaser Guarantor and each of its subsidiaries is, and has been at all times since January 1, 2014, in compliance with all Permits and with all laws and Orders applicable to it or by or to which any of its properties or assets is bound or subject (other than with respect to Permits that are not material to the Purchaser Guarantor and its subsidiaries taken as a whole), and neither the Purchaser Guarantor nor any of its subsidiaries has received any notice alleging non-compliance (other than ordinary course regulatory audits and corresponding plans of correction that are not material to the Purchaser Guarantor and its subsidiaries taken as a whole).

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Schedule 7 Conduct of the Purchaser Guarantor prior to Closing

Except as otherwise set forth on section 7 of the Purchaser Guarantor Schedules, as required by law or any applicable Order, as expressly permitted or required under the terms of this Deed or with the prior written consent of the Sellers’ Representative, which consent shall not be unreasonably withheld, delayed or conditioned, during the period from the date of this Deed to the earlier of Closing or termination of this Deed in accordance with its terms, the Purchaser Guarantor shall, and the Purchaser Guarantor shall cause each subsidiary of Purchaser Guarantor to conduct its business in the ordinary course consistent with past practice. Without limiting the generality of the foregoing, and except as otherwise set forth on section 7 of the Purchaser Guarantor Schedules, as required by law or any Order or as expressly permitted or required under the terms of the Deed, during the period from the date of this Deed through the earlier of Closing or termination of this Deed in accordance with its terms, the Purchaser Guarantor shall not, and the Purchaser Guarantor shall cause each of its subsidiaries not to, without the prior written consent of the Sellers’ Representatives, which consent shall not be unreasonably withheld, delayed or conditioned:

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Schedule 8 Actions pending Closing

The following matters require prior approval by the Purchaser in accordance with and subject to clause 4.1:

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Schedule 9 Definitions and interpretation

In this Deed, the following words and expressions shall have the following meanings:

A Ordinary Share Price means, in respect of a Seller, the amount set out opposite such Seller’s name in column 3 and, following adjustment in accordance with clause 4.11, column 5 of Part A and column 3 and, following adjustment in accordance with clause 4.11, column 5 of Part C of the Allocation Table;

A Ordinary Shares means the class A ordinary shares with a nominal value of £0.001 each in the capital of the Company;

Acadia Common Stock means the common stock, US$0.01 par value per share, of the Purchaser Guarantor;

Acadia Common Stock Consideration means 5,363,000 shares of Acadia Common Stock;

Acadia Common Stock Consideration Amount means an amount equal to US$337,547,220;

Acadia Common Stock Reduction Shares has the meaning given in clause 2.5(c);

Acadia Publicly Issued Shares has the meaning given in clause 4.6(a);

Act means the Enterprise Act 2002;

Action means any action, claim, suit, arbitration, litigation, proceeding or governmental investigation;

Additional Notes Debt means, in respect of a Seller, an amount equal to all interest (whether arising or accruing, or satisfied through the issue of “payment in kind” notes, in each case on a daily basis based on a 365-day year) on the Loan Notes held by that Seller arising or accruing in the period from but excluding the date of this Deed to and including the Closing Date;

Additional Preference Share Price means, in respect of a Seller, an amount equal to the amount of all dividends (whether arising or accruing, in each case on a daily basis based on a 365-day year) on the Preference Shares held by that Seller arising or accruing in the period from but excluding the date of this Deed to and including the Closing Date;

Adjusted Acadia Placing Stock has the meaning given in clause 2.5(b);

Affiliate means:

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but shall not include any Target Company;

Agreed Form means, in relation to a document, the form of that document which has been initialled on the date of this Deed for the purpose of identification by or on behalf of each Sellers’ Representative and the Purchaser (in each case with such amendments as may be agreed in writing by or on behalf of each Sellers’ Representative and the Purchaser);

Agreed Leakage Amount has the meaning given in clause 12.5;

Agreed Threshold Share Price means the share price specified in the document entitled “Agreed Threshold Share Price” in the Agreed Form;

Allocation Table means the Agreed Form of the allocation table;

Amended Registration Rights Agreement means the amended registration rights agreement entered into on the date of this Deed between, amongst others, the Purchaser Guarantor and the Institutional Sellers;

Articles means the articles of association of the Company adopted by a special resolution passed on 27 August 2014;

B Ordinary Share Price means, in respect of a Seller, the amount set out opposite such Seller’s name in column 7 and, following adjustment in accordance with clause 4.11, column 9 of Part C of the Allocation Table;

B Ordinary Shares means the class B ordinary shares with a nominal value of £0.001 each in the capital of the Company;

Bond Issuer means Priory Group No. 3 plc;

Business means the business of the Target Companies as carried on at the date of this Deed;

Business Day means a day other than a Saturday or Sunday or public holiday in England or the United States of America on which banks are open in London and New York for general commercial business;

C Ordinary Share Price means, in respect of a Seller, the amount set out opposite such Seller’s name in column 3 and, following adjustment in accordance with clause 4.11, column 5 of Part B and column 11 and, following adjustment in accordance with clause 4.11, column 13 of Part C of the Allocation Table;

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C Ordinary Shares means the class C ordinary shares with a nominal value of £0.001 each in the capital of the Company;

Cash Consideration Increase Amount has the meaning given in clause 2.5(c);

Cash Deduction has the meaning given in clause 2.4;

Claim means any claim under or for breach of this Deed including, without limitation, any claim for breach of the Sellers’ Warranties and any claim for Leakage;

Closing means completion of the sale and purchase of the Shares in accordance with the provisions of this Deed;

Closing Date means 16 February 2016 or such different date as may be agreed between the Purchaser and the Institutional Sellers’ Representative;

Closing Statement has the meaning given in clause 4.10;

CMA means the Competition and Markets Authority;

Companies Act means the UK Companies Act 2006;

Company means Priory Group No. 1 Limited, a company incorporated in England and Wales (company number: 7480152) having its registered office at Fifth Floor, 80 Hammersmith Road, London W14 8UD;

Company’s Account means the account of Priory Central Services Limited with sort code 20-00-00 and account number 13458571 (and/or such other account(s) as the Company and the Purchaser may agree in writing);

Compliant means, with respect to the Required Target Financial Information, that:

Confidential Information has the meaning given in clause 16.1;

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Connected Persons has the meaning given in clause 23;

Consideration Deduction Amount has the meaning given in clause 3(c);

Costs means all damages, losses, charges, liabilities, Actions, payments, judgments, settlements, interest, penalties, costs and expenses reasonably incurred (including, in each case, tax incurred thereon);

Covered Person has the meaning given in clause 11.2;

D Ordinary Share Price means, in respect of a Seller, the amount set out opposite such Seller’s name in column 7 and, following adjustment in accordance with clause 4.11, column 9 of Part A and column 15 and, following adjustment in accordance with clause 4.11, column 17 of Part C of the Allocation Table;

D Ordinary Shares means the class D ordinary shares with a nominal value of: (i) £0.001; or (ii) £500, each in the capital of the Company;

Data Room means the virtual data room administered by Merrill DataSite comprising the documents and other information relating to the Target Companies and the Business as listed on the data room index in the Agreed Form;

Debt Commitment Agreement means the debt commitment letter delivered by the Purchaser to the Sellers’ Representatives on the date hereof, together with any fee letters (in a customarily redacted form), in each case, as amended, supplemented or replaced in compliance with this Deed relating to the provision of financing to the Purchaser or any member of the Purchaser Group for the purpose of the Proposed Transaction;

Debt Financing Sources means the persons, other than the Purchaser, Purchaser Guarantor and any other member of the Purchaser’s Group, that have committed to provide or arrange or otherwise entered into agreements in connection with the Purchaser’s Debt Financing or other financings in connection with the Proposed Transaction, and parties to any joinder agreements, indentures or credit agreements entered pursuant thereto or relating thereto, together with their respective Affiliates, and their respective Affiliates’ officers, directors, employees, agents and representatives and their respective successors and assigns;

Debt Security means the security constituted by the Transaction Security Documents (as defined in the Revolving Credit Facility Agreement);

Deed of Adherence means a deed substantially in the form set out in Schedule 5;

Deed of Release means one or more deeds of release and DS1 forms (and any equivalent release document(s) or form(s) required in Scotland and/or the Cayman Islands) pursuant to which all of the Debt Security shall be released on the Closing Date, subject to receipt by the relevant recipients of the Senior Secured Bond Payoff Amount, the Senior Unsecured Bond Payoff Amount and the Outstanding RCF Debt and (notwithstanding the determination of a “material obligation” pursuant to clause 5.13), on the basis that the delivery of the DS1 forms (and any equivalent release document(s) or form(s) required in Scotland and/or the Cayman Islands) shall not be deemed to be a material obligation in respect of any Seller for the purposes of clause 5.13;

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Default Interest means interest at LIBOR plus four per cent.;

Disclosure Letter means the disclosure letter from the Warrantors (as defined therein) to the Purchaser dated the date of this Deed;

E1 Ordinary Share Price means, in respect of a Seller, the amount set out opposite such Seller’s name in column 7 and, following adjustment in accordance with clause 4.11, column 9 of Part B of the Allocation Table and column 19 and, following adjustment in accordance with clause 4.11, column 21 of Part C of the Allocation Table;

E1 Ordinary Shares means the class E1 ordinary shares with a nominal value of £0.001 each in the capital of the Company;

E2 Ordinary Share Price means, in respect of a Seller, the amount set out opposite such Seller’s name in column 23 and, following adjustment in accordance with clause 4.11, column 25 of Part C of the Allocation Table;

E2 Ordinary Shares means the class E2 ordinary shares with a nominal value of £0.001 each in the capital of the Company;

Election Notice has the meaning given in clause 2.6;

Equity Financing Sources means the underwriters of the Public Equity Offering, together with their respective Affiliates, and their respective Affiliates’ officers, directors, employees, agents and representatives and their respective successors and assigns;

Equity Proceeds means the net proceeds actually received by the Purchaser Guarantor in connection with the Public Equity Offering (including net proceeds actually received by the Purchaser Guarantor in connection with the Option Closing provided the Option Closing occurs prior to the date that is five Business Days before the Closing Date), less the amount of all fees, costs and expenses (including underwriting discounts and commissions) incurred or to be incurred by the Purchaser Group or arising in connection with the Public Equity Offering;

Executive Management Team Members means Tom Riall, Mark Moran, Trevor Torrington, Mark Underwood, Sarah Hughes, Sam Rogers, David Hall, Claire Balmforth, Tina Walton, Adrian Pancott, Christopher Screech, Tom Muir, Sylvia Tang and Sian Wicks;

Fund VI Affiliate means Advent International GPE VI Limited Partnership, Advent International, GPE VI-A Limited Partnership, Advent International GPE VI-B Limited Partnership, Advent International GPE VI-C Limited Partnership, Advent International GPE VI-D Limited Partnership, Advent International GPE VI-E Limited Partnership, Advent International GPE VI-F Limited Partnership, Advent International GPE VI-G Limited Partnership, Advent Partners GPE VI 2008 Limited Partnership, Advent Partners GPE VI 2009 Limited Partnership, Advent Partners GPE VI 2010 Limited Partnership, Advent Partners GPE VI-A Limited Partnership and Advent Partners GPE VI-A 2010 Limited Partnership;

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GAAP means U.S. generally accepted accounting principles;

Individual Seller means Tom Riall;

Initial Acadia Common Stock Reduction Shares has the meaning given in clause 2.5(b);

Initial Cash Consideration Increase Amount has the meaning given in clause 2.5(a);

Initial Cash Price means, in respect of a Seller, an amount equal to the aggregate of the relevant: (a) Initial Ordinary Share Price; and (b) Initial Preference Share Price, as applicable;

Initial Ordinary Share Price means, in respect of a Seller, an amount equal to the aggregate of the relevant: (a) A Ordinary Share Price; (b) B Ordinary Share Price; (c) C Ordinary Share Price; (d) D Ordinary Share Price; (e) E1 Ordinary Share Price; and (f) E2 Ordinary Share Price;

Initial Notes Debt means, in respect of a Seller, the amount set out opposite such Seller’s name in column 14 of Part A and column 30 of Part C of the Allocation Table;

Initial Preference Share Price means, in respect of a Seller, the amount set out opposite such Seller’s name in column 11 of Part A and column 27 of Part C of the Allocation Table;

Initial Seller Acadia Placing Shares has the meaning given in clause 2.5(a);

Institutional Sellers’ Account means such bank account(s) of the Institutional Sellers as the Institutional Sellers’ Representative notifies to the Purchaser in writing no less than five Business Days prior to Closing;

Institutional Sellers’ Pricing Representative means Tom Allen (Managing Director) of Advent International plc, unless the Institutional Sellers’ Representative elects to nominate (by notice in writing to the Purchaser) such other person of Advent International plc in his place, in which case that person shall be the Institutional Sellers’ Pricing Representative;

Institutional Sellers’ Representative has the meaning given in clause 10.1;

Investment Documents means:

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knowledge of the Purchaser Guarantor means the actual knowledge of Joey Jacobs (Chairman and Chief Executive Officer), Brent Turner (President), David Duckworth (Chief Financial Officer) and Christopher L. Howard (EVP, General Counsel and Secretary);

Leakage means, in each case to, or on behalf of, or for the benefit of a Seller or any of its Affiliates:

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LIBOR means the display rate per annum of the offered quotation for deposits in pounds sterling for a period of one month which appears on the appropriate page of the Reuters Screen (or such other page as the parties may agree) at or about 11.00 a.m. London time on the date on which payment of the sum under this Deed was due but not paid;

Liens means lien, security interest, mortgage, pledge, charge or similar matter affecting title, or other encumbrance;

Loan Note Instruments means: (i) the unsecured loan note instrument executed by the Company dated 4 March 2011 constituting £130,000,000 unsecured subordinated loan notes and unsecured PIK notes due 2060; and (ii) the unsecured loan note instrument executed by the Company dated 14 April 2011 constituting £51,548,613 unsecured subordinated loan notes and unsecured PIK notes due 2057;

Loan Notes means the unsecured subordinated loan notes constituted by the Loan Note Instruments;

Locked Box Date means 31 October 2015;

Management Employee means each of the Executive Management Team Members and the Specialist Directors (as defined in the Management Warranty Deed);

Management Sellers’ Account means the DLA Piper UK LLP Client Account with sort code 60-60-05 and account number 86467654 (and/or such other account(s) as the Management Sellers’ Representative and the Purchaser may agree in writing);

Management Sellers’ Representative has the meaning given in clause 10.1;

Management Warranty Deed means the management warranty deed entered into on or around the date hereof between the Warrantors (as defined therein) and the Purchaser;

Notes means the Loan Notes and the PIK Notes;

Option Acadia Common Stock Reduction Shares has the meaning given in clause 2.5(c);

Option Cash Consideration Increase Amount has the meaning given in clause 2.5(c);

Option Closing means any closing related to the exercise by the underwriters in the Public Equity Offering of the option (granted to them by the Purchaser Guarantor in the underwriting agreement entered into in connection with the Public Equity Offering) to acquire (or be issued) additional shares of Acadia Common Stock;

Ordinary Shares means the A Ordinary Shares, the B Ordinary Shares, the C Ordinary Shares, the D Ordinary Shares, the E1 Ordinary Shares and the E2 Ordinary Shares;

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Outstanding Debt means together the Outstanding Notes Debt and the Outstanding RCF Debt;

Outstanding Notes Debt means the aggregate of the Initial Notes Debt and the Additional Notes Debt;

Outstanding RCF Debt means the aggregate amount required to be paid by the Target Companies in order to: (i) discharge all amounts outstanding under the Revolving Credit Facility Agreement (and to cancel the facility made available thereunder) and the other Finance Documents (as defined in the Revolving Credit Facility Agreement); and (ii) release the Debt Security, in each case on the Closing Date (including, without limitation, all amounts of principal, accrued interest, fees, costs, expenses and break costs);

parent undertaking has the meaning given in the Companies Act;

Permits means approvals, authorisations, licences, registrations and permits of governmental or regulatory authorities;

Permitted Leakage means those items of Leakage detailed in Schedule 3;

PIK Notes means the “payment in kind” notes constituted by the Loan Note Instruments;

Preference Shares means the 12 per cent. cumulative redeemable preference shares with a nominal value of £1.00 each in the capital of the Company;

Pricing Date means the date on which the Public Equity Offering Price is determined as between the Purchaser Guarantor and the lead underwriter of the Public Equity Offering and on which the underwriting agreement in connection with the Public Equity Offering is signed;

Proposed Transaction means the transactions contemplated by the Transaction Documents;

Pro Rata means, with respect to an Institutional Seller, the proportion of the aggregate amount of consideration to be received by that Institutional Seller as against the aggregate amount of consideration to be received by all Institutional Sellers, in each case under the terms of this Deed (in each case disregarding for this purpose the application of clauses 2.4 to 2.6);

Public Equity Offering has the meaning given in clause 4.5;

Public Equity Offering Price means the initial public offering price per share of Acadia Common Stock paid by investors in the Public Equity Offering;

Public Offering has the meaning given in clause 4.5;

Purchaser Credit Agreement means the Amended and Restated Credit Agreement dated as of December 31, 2012 among Acadia, the subsidiaries of the Acadia party thereto, Bank of America, N.A. as administrative agent, swing line lender and L/C issuer and the other parties thereto (as amended, modified or otherwise supplemented prior to the date hereof);

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Purchaser Debt Agreements means the Purchaser Credit Agreement and the Purchaser Indentures;

Purchaser Group means the Purchaser and its Affiliates from time to time;

Purchaser Guaranteed Obligations has the meaning given in clause 14.1;

Purchaser Guarantor Credit Agreement means that certain Amended and Restated Credit Agreement dated as of December 31, 2012 (as amended by that certain Consent and First Amendment dated as of March 11, 2013, as further amended by that certain Second Amendment dated as of June 28, 2013, as further amended by that certain Third Amendment dated as of September 30, 2013, as further amended by that certain Fourth Amendment dated as of February 13, 2014, as further amended by that certain Fifth Amendment dated as of June 16, 2014 and as may be further amended, restated, supplemented or otherwise modified from time to time), by and among the Purchaser Guarantor, certain of the Purchaser Guarantor’s subsidiaries as guarantors, the financial institutions from time to time party thereto as lenders, and Bank of America, N.A., as administrative agent for the lenders;

Purchaser Guarantor Reports means all reports, schedules, forms, statements, certifications and other documents filed by the Purchaser Guarantor with the SEC from January 1, 2015 to the close of business of the second Business Day prior to the date hereof;

Purchaser Guarantor Warranties means the warranties given by the Purchaser Guarantor pursuant to clause 7 and Schedule 6;

Purchaser Indentures means (1) the Indenture dated as of March 12, 2013, by and among the Borrower, the subsidiaries of the Borrower party thereto and U.S. Bank National Association, as trustee and the 6.125% notes issued thereunder, (2) the indenture dated as of July 4, 2014, by and among the Borrower, the subsidiaries of the Borrower party thereto and U.S. Bank National Association, as trustee and the 5.125% notes issued thereunder) and (3) the indenture dated as of February 11, 2015, by and among the Borrower, the subsidiaries of the Borrower party thereto and U.S. Bank National Association, as trustee and the 5.625% notes issued thereunder, in each case as amended, modified for supplemented prior to the date hereof;

Purchaser Obligation means any representation, warranty or undertaking to pay given by the Purchaser to the Sellers (or any of them) under this Deed;

Purchaser Warranties means the warranties given by the Purchaser and the Purchaser Guarantor pursuant to clause 7;

Purchaser’s Bank Account means such bank account(s) of the Purchaser as the Purchaser notifies to the Sellers’ Representatives in writing no less than five Business Days prior to Closing;

Purchaser’s Counsel means Andrew Edge (failing which another partner in the corporate department) of Stephenson Harwood LLP, 1 Finsbury Circus, London EC2M 7SH;

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Purchaser’s Debt Financing means the financings incurred or intended to be incurred pursuant to the Debt Commitment Agreement;

Purchaser’s Financing means, collectively, the Purchaser’s Debt Financing and the Public Equity Offering;

Regulation S means Regulation S under the Securities Act;

Relevant Affiliate means each Fund VI Affiliate, Advent International plc and Advent International Corporation;

Relevant Employee means any employee of a Target Company who is classified as a tier 1, tier 2, tier 3, tier 4, tier 5 or tier 6 employee for the purposes of that Target Company’s personnel records;

Relevant Seller has the meaning given in clause 12.5;

Relief includes, unless the context otherwise requires, any allowance, credit, deduction, exemption or set off in respect of any tax or relevant to the computation of any income, profits or gains for the purposes of any tax, or any right to or actual repayment of or saving of tax (including any repayment supplement, fee or interest in respect of tax);

Representatives has the meaning given in clause 16.1;

Required Target Financial Information has the meaning given in clause 4.1(b)(i);

Revised Schedule has the meaning given in clause 4.11;

Revolving Credit Facility Agreement means the senior revolving facility agreement entered into between, amongst others, Priory Group No.3 plc, the Arranger (as defined therein) and the Original Lenders (as defined therein) on 3 February 2011 (as amended and/or amended and restated from time to time);

Sarbanes-Oxley Act means Sarbanes-Oxley Act 2002, as amended and the applicable rules and regulations thereunder;

SEC means the United States Securities and Exchange Commission;

Securities Act means the United States Securities Act of 1933;

Seller Obligation means any representation, warranty or undertaking to pay given by the Sellers (or any of them) to the Purchaser under this Deed;

Sellers’ Disclosed Transaction Costs means the Sellers’ Transaction Costs as set out in the Closing Statement;

Sellers’ Representatives means the Institutional Sellers’ Representative and the Management Sellers’ Representative;

Sellers’ Transaction Costs means any professional fees, expenses or other costs paid or agreed to be paid or incurred or owing by any Target Company in connection with the implementation of the Proposed Transaction (including any bonuses paid or payable in connection with the implementation of the Proposed Transaction and any

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income tax, national insurance contributions or social security contributions relating to any such bonuses and payable by a Target Company), or the potential initial public offering of any of the Target Companies or any holding company of any of the Target Companies, or to Knight Frank in relation to a valuation report, since the Locked Box Date (but excluding such costs and expenses referred to in clause 4.9(a));

Sellers’ Warranties means the warranties given by the Sellers pursuant to clause 6;

Senior Secured Bonds means the 7% senior secured notes due 2018 issued by the Bond Issuer pursuant to the Senior Secured Bond Indenture, which are outstanding in the principal amount of £386,300,000;

Senior Secured Bond Indenture means the indenture dated 3 February 2011 between Priory Group No. 3 plc (formerly Crown Newco 3 plc) and Deutsche Trustee Company Limited, as trustee, Deutsche Bank AG London Branch, as security agent, principal paying agent, and transfer agent, and Deutsche Bank Luxembourg S.A., as registrar, Luxembourg paying agent and transfer agent;

Senior Secured Bond Payoff Amount means an amount sufficient to pay in full the principal of, premium, if any, interest and other fees, costs, expenses and other amounts due on the Senior Secured Bonds or under the Senior Secured Notes Documents (as defined in the Revolving Credit Facility Agreement) in order to: (i) redeem the Senior Secured Bonds in full; and (ii) release the Debt Security, in each case on the Closing Date;

Senior Secured Bond Trustee means Deutsche Trustee Company Limited, as trustee;

Senior Unsecured Bonds means the 8.875% senior unsecured notes due 2019 issued by the Bond Issuer pursuant to the Senior Unsecured Bond Indenture, which are outstanding in the principal amount of £175,000,000;

Senior Unsecured Bond Indenture means the indenture dated 3 February 2011 between Priory Group No. 3 plc (formerly Crown Newco 3 plc) and Deutsche Trustee Company Limited, as trustee, Deutsche Bank AG London Branch, as principal paying agent and transfer agent, and Deutsche Bank Luxembourg S.A. as registrar, Luxembourg paying agent and transfer agent;

Senior Unsecured Bond Payoff Amount means an amount sufficient to pay in full the principal of, premium, if any, interest and other fees, costs, expenses and other amounts due on the Senior Unsecured Bonds or under the Senior Unsecured Notes Documents (as defined in the Revolving Credit Facility) in order to redeem the Senior Unsecured Bonds in full on the Closing Date;

Senior Unsecured Bond Trustee means Deutsche Trustee Company Limited, as trustee;

Share Price means the aggregate of an amount equal to the Initial Cash Price and the Additional Preference Share Price for all Sellers;

Shares means the shares in the capital of the Company set out in the Allocation Table, comprising the A Ordinary Shares, the B Ordinary Shares, the C Ordinary Shares, the D Ordinary Shares, the E1 Ordinary Shares, the E2 Ordinary Shares and the Preference Shares;

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subsidiary undertaking has the meaning given in the Companies Act;

Surviving Provisions means clauses 12.5 ( Payments ), 15 ( Announcements ), 16 ( Confidentiality ), 19 ( Assignment ), 20 ( Costs ), 21 ( Notices ), 0 ( Conflict with other agreements ), 23 ( Whole agreement ), 25 ( Waiver, rights and remedies ), 28 ( Variations ), 29 ( Invalidity ), 30 ( Third party enforcement rights ), 31 ( Governing law and jurisdiction ) and Schedule 9 ( Definitions and interpretation );

Target Companies means the Company and its subsidiary undertakings, and Target Company means any of them;

tax or taxation means: (a) taxes on income, profits and gains; and (b) all other taxes, levies, duties, imposts, charges and withholdings in the nature of taxation, including any excise, property, value added, sales, transfer, franchise and payroll taxes, and any national insurance or social security contributions, together with all penalties, charges, fees and interest relating to any of the foregoing or to any late or incorrect return in respect of any of them;

Tax Authority means any taxing or other authority (whether within or outside the United Kingdom) competent to impose any tax liability or assess or collect any tax;

Tax Liabilities Amount has the meaning given in clause 3(a);

Third Party Right means any interest or equity of any person (including any right to acquire, option or right of pre-emption or conversion) or any mortgage, charge, pledge, lien, assignment, hypothecation, security interest, title retention or any other security agreement or arrangement, or any agreement to create any of the above;

Transaction Documents means this Deed, the Management Warranty Deed, the Disclosure Letter and any other documents in Agreed Form;

Trustee’s Account means the account of ATJL Priory Equity Plan Employee Trust with sort code 16-10-28 and account number 50791241 (and/or such other account(s) as the Trustee and the Purchaser may agree in writing);

VAT means value added tax and any similar sales or turnover tax; and

Working Hours means 9.30am to 5.30pm in the relevant location on a Business Day.

In this Deed, unless the context otherwise requires:

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Except as otherwise expressly provided in this Deed, any express reference to an enactment (which includes any legislation in any jurisdiction) includes references to: (i) that enactment as amended, consolidated or re-enacted by or under any other enactment before or after the date of this Deed; (ii) any enactment which that enactment re-enacts (with or without modification); and (iii) any subordinate legislation (including regulations) made (before or after the date of this Deed) under that enactment, as amended, consolidated or re-enacted as described at (i) or (ii) above, except to the extent that any of the matters referred to in (i) to (iii) occurs after the date of this Deed and increases or alters the liability of the Sellers or the Purchaser under this Deed.

The Schedules comprise schedules to this Deed and form part of this Deed.

Where there is any inconsistency between the definitions set out in this Schedule and the definitions set out in any clause or any other Schedule, then, for the purposes of construing such clause or Schedule, the definitions set out in such clause or Schedule shall prevail.

Except as otherwise provided in this Deed, the obligations of each of the Sellers under this Deed are entered into on a several basis and no claim may be made against any Seller in respect of the performance of any obligations under, or any breach of, this Deed by any other Seller.

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IN WITNESS WHEREOF this Deed has been duly executed by the parties and is intended to be and is hereby delivered on the date first above written.