SIXTH AMENDMENT

Exhibit 10.1

SIXTH AMENDMENT

THIS SIXTH AMENDMENT (this “Amendment”), dated as of November 9, 2012, to the Credit Agreement referenced below is by and among Acadia Healthcare Company, Inc. (f/k/a Acadia Healthcare Company, LLC), a Delaware corporation (the “Borrower”), the Guarantors identified on the signature pages hereto, the Lenders identified on the signature pages hereto and Bank of America, N.A., in its capacity as Administrative Agent (in such capacity, the “Administrative Agent”).

W I T N E S S E T H

WHEREAS, revolving credit and term loan facilities have been extended to the Borrower pursuant to the Credit Agreement (as amended, modified, supplemented, increased and extended from time to time, the “Credit Agreement”) dated as of April 1, 2011, by and among the Borrower, the Guarantors identified therein, the Lenders identified therein and the Administrative Agent; and

WHEREAS, the Borrower has requested certain modifications to the Credit Agreement and the Required Lenders have agreed to such modifications to the Credit Agreement on the terms and conditions set forth herein.

NOW, THEREFORE, IN CONSIDERATION of the premises and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties hereto agree as follows:

1. Defined Terms. Capitalized terms used herein but not otherwise defined herein shall have the meanings provided to such terms in the Credit Agreement.

2. Amendments. The Credit Agreement is amended as follows:

2.1 In the definition of “Consolidated EBITDA” in Section 1.01, in clause (b) the “and” after clause (xxvii) is deleted and replaced with a “;” and a new clause (xxix) is inserted after clause (xxviii) to read as follows:

and; (xxix) for any period of four fiscal quarters ending after the effective date of the Sixth Amendment to this Agreement, fees and out-of-pocket expenses incurred in such period in connection with any Permitted Acquisition (whether or not consummated) in an amount not to exceed 10% of the aggregate consideration of such Permitted Acquisition; provided, that the aggregate amount of fees and out-of-pocket expenses added back pursuant to this clause (xxix) for all Permitted Acquisitions in such period shall not exceed $3,000,000;

2.2 The following definitions are added to Section 1.01 in the appropriate alphabetical order to read as follows:

“Park Royal” means, The Pavilion at HealthPark, LLC, a Florida limited liability company, d/b/a Park Royal Hospital.

“Park Royal IRB Debt” has the meaning specified in Section 8.03.

2.3 In Section 7.12 of the Credit Agreement the following is added to the end of that section before the period:

provided, that Park Royal shall not be required to become a Guarantor so long as the Park Royal IRB Debt prohibits Park Royal from granting a Guaranty of the Obligations.

2.4 In Section 8.01 of the Credit Agreement the “and” after clause (t) is deleted, clause (u) is renumbered clause (v) and a new clause (u) is added after clause (t) to read as follows:

(u) Liens securing the Park Royal IRB Debt; provided that (i) such Lien does not at any time encumber any property other than the assets of Park Royal described in the documents governing the Park Royal IRB Debt as of the date of the Permitted Acquisition of Park Royal; and

2.5 In Section 8.02 of the Credit Agreement, the “and” after clause (j) is deleted, clause (k) is renumbered clause (m) and a new clauses (k) and (l) are inserted to read as follows:

(k) Investments in Park Royal for working capital in an amount not to exceed $3 million in the aggregate at any time outstanding;

(l) Investments by any Loan Party consisting of the purchase of bonds issued by the Lee County Industrial Development Authority, the proceeds of which were used to fund the Park Royal IRB Debt; provided that no Event of Default shall have occurred and be continuing at the time of such purchase; and

2.6 In Section 8.03 of the Credit Agreement clause (f) is amended in its entirety to read as follows:

(f) Guarantees with respect to Indebtedness permitted under this Section 8.03 other than the Park Royal IRB Debt;

2.7 In Section 8.03 of the Credit Agreement clause (n) is renumbered clause (o) and a new clause (n) is added after clause (m) to read as follows:

(n) Indebtedness of Park Royal constituting loans from the Lee County Industrial Development Authority in an amount not to exceed $23 million assumed in connection with the Permitted Acquisition of Park Royal (the “Park Royal IRB Debt”); and

3. Conditions Precedent. This Amendment shall become effective as of the date hereof upon receipt by the Administrative Agent of counterparts of this Amendment executed by the Borrower, the Guarantors, the Required Lenders and the Administrative Agent.

4. Amendment is a “Loan Document”. This Amendment is a Loan Document and all references to a “Loan Document” in the Credit Agreement and the other Loan Documents (including, without limitation, all such references in the representations and warranties in the Credit Agreement and the other Loan Documents) shall be deemed to include this Amendment.

5. Representations and Warranties; No Default. Each Loan Party represents and warrants to the Administrative Agent and each Lender that after giving effect to this Amendment (a) the representations and warranties of each Loan Party contained in the Credit Agreement or any other Loan Document, or which are contained in any document furnished at any time under or in connection with the Credit Agreement or any other Loan Document are true and correct in all material respects on and as of the date hereof, except to the extent that such representations and warranties specifically refer to an earlier date, in which case such representations and warranties are true and correct in all material respects as of such earlier date, and (b) no Default exists.

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6. Reaffirmation of Obligations. Each Loan Party (a) acknowledges and consents to all of the terms and conditions of this Amendment, (b) affirms all of its obligations under the Loan Documents and (c) agrees that this Amendment does not operate to reduce or discharge such Loan Party’s obligations under the Loan Documents.

7. Reaffirmation of Security Interests. Each Loan Party (a) affirms that each of the Liens granted in or pursuant to the Loan Documents are valid and subsisting and (b) agrees that this Amendment does not in any manner impair or otherwise adversely affect any of the Liens granted in or pursuant to the Loan Documents.

8. No Other Changes. Except as modified hereby, all of the terms and provisions of the Loan Documents shall remain in full force and effect.

9. Counterparts; Delivery. This Amendment may be executed in counterparts (and by different parties hereto in different counterparts), each of which shall constitute an original, but all of which when taken together shall constitute a single contract. Delivery of an executed counterpart of this Amendment by facsimile or other electronic imaging means shall be effective as an original.

10. Governing Law. This Amendment shall be deemed to be a contract made under, and for all purposes shall be construed in accordance with, the laws of the State of New York.

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IN WITNESS WHEREOF, the parties hereto have caused this Sixth Amendment to be duly executed as of the date first above written.

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