STOCKHOLDER SUPPORT AGREEMENT

                  THIS  STOCKHOLDER  SUPPORT  AGREEMENT  dated as of October 24,
1997 (this  "Agreement"),  is entered into by MBC  Associates,  L.P., a Delaware
limited  partnership  ("MBC  Associates"),  KKR  Partners  II,  L.P., a Delaware
limited   partnership  ("KKR  Partners"),   38  Newbury   Ventures/MBC   Limited
Partnership, a Massachusetts limited partnership ("Newbury"),  Albert S. Waxman,
the Albert S. Waxman Family Charitable  Remainder Unitrust (the "Waxman Trust"),
Arthur H. Halper,  Michael G. Lenahan and John A. Budnick to and for the benefit
of Magellan Health Services,  Inc., a Delaware corporation  ("Parent").  Each of
MBC  Associates,  KKR  Partners,  Newbury,  Albert S. Waxman,  the Waxman Trust,
Arthur H. Halper,  Michael G. Lenahan and John A. Budnick are referred to herein
as a "Stockholder"  and collectively as the  "Stockholders."  Capitalized  terms
used  and not  otherwise  defined  herein  shall  have the  respective  meanings
assigned to them in the Merger Agreement referred to below.

                  WHEREAS,  as of  the  date  hereof,  MBC  Associates  and  KKR
Partners own of record and  beneficially  20,678,600  shares and 321,400 shares,
respectively  (such  aggregate   21,000,000  shares  being  referred  to  herein
collectively  as the "KKR  Shares"),  of common stock,  par value $.01 per share
("Common Stock"), of Merit Behavioral Care Corporation,  a Delaware  corporation
(the "Company");

                  WHEREAS,  as of the date  hereof,  Newbury  owns of record and
beneficially 600,000 shares (the "Newbury Shares") of Common Stock;

                  WHEREAS,  as of the date  hereof,  Albert  S.  Waxman  and the
Waxman Trust own of record and  beneficially  1,055,100  and  1,000,000  shares,
respectively (such aggregate  2,055,100 shares being referred to collectively as
the "Waxman Shares"), of Common Stock;

                  WHEREAS, as of the date hereof Arthur H. Halper owns of record
and beneficially 100,000 shares of Common Stock (the "Halper Shares");

                  WHEREAS,  as of the date  hereof  Michael G.  Lenahan  owns of
record and beneficially 100,000 shares of Common Stock (the "Lenahan Shares");

                  WHEREAS,  as of the date hereof John A. Budnick owns of record
and  beneficially  50,000  shares of Common  Stock (the  "Budnick  Shares,"  and
collectively with the KKR Shares,  Newbury Shares,  Waxman Shares, Halper Shares
and Lenahan Shares,  together with any other voting or equity  securities of the
Company hereafter acquired by any Stockholders  beneficially or of record, prior
to the termination of this Agreement, the "Shares");

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                  WHEREAS,  concurrently  with the execution of this  Agreement,
Parent, the Company and MBC Merger Corporation,  a Delaware corporation ("Merger
Sub"),  are entering into an Agreement and Plan of Merger,  dated as of the date
hereof (the "Merger  Agreement"),  pursuant to which, upon the terms and subject
to the conditions  thereof,  Merger Sub will be merged with and into the Company
(the "Merger")  such that the Company will become a  wholly-owned  subsidiary of
Parent; and

                  WHEREAS,  as a condition to the willingness of Parent to enter
into the Merger Agreement,  Parent has requested the Stockholders  agree, and in
order to induce Parent to enter into the Merger Agreement,  the Stockholders are
willing to consent to the adoption of the Merger  Agreement  and the approval of
the Merger and to agree,  severally but not jointly,  to certain other  matters,
all upon the terms and subject to the conditions set forth herein.

                  NOW,  THEREFORE,  in  consideration  of the  foregoing and the
mutual covenants and agreements  contained  herein,  and intending to be legally
bound hereby, the parties hereby agree, severally and not jointly, as follows:

                  Section 1. Consent;  Voting of Shares. Each Stockholder hereby
(a) agrees that,  at any meeting of the  stockholders  of the  Company,  however
called,  and in any action by consent of the stockholders of the Company in lieu
of a meeting,  such Stockholder will vote all of its respective  Shares in favor
of the adoption of the Merger Agreement and approval of the Merger and the other
transactions  contemplated  by  the  Merger  Agreement  and  hereby  irrevocably
consents to the adoption of the Merger  Agreement and the approval of the Merger
and the other  transactions  contemplated  by the Merger  Agreement,  (b) agrees
that, at any meeting of the stockholders of the Company,  however called, and in
any action by consent of the  stockholders  of the Company in lieu of a meeting,
such  Stockholder  will vote all of the Shares  against any action or  agreement
that  would  result  in a  breach  of any  representation,  warranty,  covenant,
agreement or other obligation of the Company under the Merger Agreement or which
could result in any of the  conditions  to the Company's  obligations  under the
Merger Agreement not being fulfilled,  and (c) agrees that until the termination
of this  Agreement  in  accordance  with the terms  hereof at any meeting of the
stockholders  of the  Company,  however  called,  and , in any action by written
consent of the  stockholders of the Company,  such  Stockholder will vote all of
its respective Shares in favor of any other matter necessary to the consummation
of the  transactions  contemplated by the Merger  Agreement.  In addition,  each
Stockholder  agrees  that it will,  upon  request  by  Parent,  furnish  written
confirmation,  in form and substance reasonably  satisfactory to Parent, of such
Stockholder's  support for the Merger Agreement and the Merger. Each Stockholder
acknowledges receipt and review of a copy of the Merger

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Agreement.

                  Section 2. Transfer of Shares.  Except as contemplated  hereby
or by the Merger  Agreement,  each Stockholder  agrees not to (a) offer to sell,
sell, assign,  transfer  (including by merger or otherwise by operation of law),
pledge,  encumber or  otherwise  dispose of any of its  respective  Shares,  (b)
deposit any of its respective  Shares into a voting trust or enter into a voting
agreement or  arrangement  with respect to any such Shares or grant any proxy or
power of attorney with respect thereto or (c) enter into any contract, option or
other  arrangement or  undertaking  with respect to the direct or indirect sale,
assignment,  transfer  (including by merger or otherwise by operation of law) or
other  disposition of or transfer of any interest in or the voting of any of its
respective Shares or any other securities of the Company.

                  Section 3. No  Solicitation.  From the date  hereof  until the
Effective Time, each Stockholder hereby covenants and agrees not to (a) solicit,
encourage  or  entertain  inquiries  or  proposals  or  initiate,  enter into or
continue any  discussions,  negotiations  or agreements  relating to the sale or
other  disposition  of the Company  (whether  through a merger,  reorganization,
stock  purchase of  otherwise) or a material  portion of it assets,  properties,
businesses  or operations  (a "Proposed  Acquisition")  to or with any person or
entity  other than Parent or Merger  Sub,  (b)  provide  any  assistance  or any
information  to any person or entity other than Parent or Merger Sub relating to
any Proposed Acquisition,  or (c) take any action inconsistent with the purposes
and  provisions  of  this  Agreement.  Each  Stockholder  agrees  that  it  will
immediately   cease  and  cause  to  be  terminated  any  existing   activities,
discussions or  negotiations  with any parties (other than Parent or Merger Sub)
heretofore  conducted,  or the provision of any  information to any party (other
than Parent or Merger Sub) to which  information  heretofore  has been provided,
with  respect  to any  Proposed  Acquisition.  If,  after the date  hereof,  any
Stockholder receives any such inquiry or proposal or request for information, or
offer to discuss or negotiate any Proposed  Acquisition,  such  Stockholder will
immediately provide notice thereof to Parent.

                  Section 4.  Termination.  This Agreement  shall terminate upon
the earlier to occur of (i) the Effective  Time or (ii) any  termination  of the
Merger  Agreement  in  accordance  with the  terms  thereof;  provided  that the
provisions of Section 8 shall survive any  termination  of this  Agreement,  and
provided further that no such  termination  shall relieve any party of liability
for a breach hereof prior to termination.

                  Section 5.        Representations.  Each Stockholder
 represents and warrants to Merger Sub and Parent as follows:


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                  (a) Such  Stockholder is the sole record and beneficial  owner
of,  and has good  title  to,  all of the  Shares  it owns as  specified  in the
Recitals hereof, and there exist no restrictions on transfer,  options, proxies,
voting  agreements,  voting  trusts or liens  affecting  said Shares,  except as
imposed  by law or as  contained  in the  respective  agreements  to which  such
Stockholder  is a party  disclosed  in Section  3.03 of the  Company  Disclosure
Schedule  (collectively  with  respect  to all  Stockholders,  the  "Stockholder
Agreements").

                  (b) The  execution  and  delivery  of this  Agreement  by such
Stockholder does not, and the performance by such Stockholder of its obligations
hereunder  will not,  constitute  a violation  of,  conflict  with,  result in a
default (or an event which,  with notice or lapse of time or both,  would result
in a default)  under, or result in the creation of any lien on any of its Shares
under, (i) any contract  commitment,  agreement,  understanding,  arrangement or
restriction  of any kind to which such  Stockholder  is a party or by which such
Stockholder  or its  Shares are bound  (other  than the  Stockholder  Agreements
applicable to such  Stockholder),  (ii) any  judgment,  writ,  decree,  order or
ruling  affecting such  Stockholder or its Shares,  or (iii) the  organizational
documents  of  such  Stockholder  to  the  extent  such  Stockholder  is  not an
individual.

                  (c) Such  Stockholder has full power and authority to execute,
deliver  and  perform  this  Agreement  and  to  consummate   the   transactions
contemplated hereby. This Agreement has been duly and validly authorized by such
Stockholder,  and the execution,  delivery and performance of this Agreement and
the  consummation  of the  transactions  contemplated  hereby have been duly and
validly  authorized  and no other  actions on the part of such  Stockholder  are
necessary  to  authorize  this  Agreement  or  to  consummate  the  transactions
contemplated  hereby.  This  Agreement  has been duly and validly  executed  and
delivered by such Stockholder  and,  assuming due  authorization,  execution and
delivery by the Parent and Merger Sub, constitutes a valid and binding agreement
of such Stockholder, enforceable against such Stockholder in accordance with its
terms,  except to the extent that  enforceability  may be limited by  applicable
bankruptcy,  reorganization,  insolvency, moratorium or other laws affecting the
enforcement of creditor's rights generally and by general  principles of equity,
regardless  of whether such  enforceability  is  considered  in a proceeding  in
equity or at law.

                  Section 6.  Appraisal  Rights.  Until the  termination of this
Agreement in accordance with the terms hereof,  each Stockholder  agrees that it
will not exercise any rights to dissent from the Merger or request  appraisal of
its respective  Shares  pursuant to Section 262 of the DGCL or any other similar
provisions of Law.

                  Section 7.        Specific Performance.  The parties hereto
 agree that irreparable damage would occur in the event any provision of this 
Agreement were not performed in accordance with the

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terms hereof and that the parties shall be entitled to specific  performance  of
the terms hereof, in addition to any other remedy at law or in equity.

                  Section 8.        Miscellaneous.

(a) This Agreement  constitutes the entire agreement  between the parties hereto
with respect to the subject matter hereof and  supersedes  all prior  agreements
and  understandings,  both  written and oral,  between the parties  with respect
thereto.  This Agreement may not be amended,  modified or rescinded except by an
instrument in writing signed by each of the parties hereto.

(b) If any term or other  provision  of this  Agreement  is invalid,  illegal or
incapable  of being  enforced  by any rule of law, or public  policy,  all other
conditions and provisions of this Agreement  shall  nevertheless  remain in full
force and effect.  Upon such  determination  that any term or other provision is
invalid,  illegal or  incapable  of being  enforced,  the parties  hereto  shall
negotiate  in good faith to modify this  Agreement  so as to effect the original
intent of the parties as closely as possible to the fullest extent  permitted by
applicable law in a mutually  acceptable  manner in order that the terms of this
Agreement remain as originally contemplated to the fullest extent possible.

(c) This  Agreement  shall be governed by and construed in  accordance  with the
laws of the State of Delaware  without  regard to the principles of conflicts of
law thereof.

(d)  Notwithstanding   anything  herein  to  the  contrary,  the  covenants  and
agreements  set  forth  herein  shall  not  prevent  any  of  the  Stockholders'
designees,  partners  or  affiliates  serving on the Board of  Directors  of the
Company  from taking any action,  subject to the  applicable  provisions  of the
Merger Agreement, while acting in such capacity as a director of the Company.

(e)  Notwithstanding  any  provisions  hereof,  none of the  obligations  of any
Stockholder  under or  contemplated  by this Agreement shall be an obligation of
(i) any officer,  director,  stockholder,  limited  partner,  general partner or
owner of such  Stockholder,  or any of  their  respective  officers,  directors,
stockholders,  limited  partners,  general partners or owners,  or successors or
assigns or (ii) any other Stockholder. Each Stockholder shall be the only person
or entity liable with respect to its  obligations.  Any monetary  liability of a
Stockholder  under this Agreement shall be satisfied solely out of the assets of
such Stockholder.  Each Stockholder  hereby  irrevocably waives any right it may
have against any such officer, director,  stockholder,  limited partner, general
partner,  owner,  successor  or  assign  identified  above  as a  result  of the
performance of the provisions under or

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contemplated  by this  Agreement.  Nothing in this  Section  8(e) shall  prevent
Parent from obtaining specific enforcement of the obligations of any Stockholder
under this Agreement.  (f) This Agreement may be executed in counterparts,  each
of which shall be deemed an original and all of which together shall  constitute
one and the same instrument.

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IN WITNESS  WHEREOF,  each of the parties hereto has caused this Agreement to be
signed by their respective duly authorized officers as of the date first written
above.

                              MBC ASSOCIATES, L.P.

                              By:     KKR Associates, L.P.
                              Its:  General Partner
                              /s/  JAMES H. GREENE, JR.
                              By:  James H. Greene, Jr.
                              Its:   General Partner

                              KKR PARTNERS II, L.P.
   
                              By:     KKR Associates, L.P.
                              Its:  General Partner
                              /s/  JAMES H. GREENE, JR.
                              By:  James H. Greene, Jr.
                              Its:   General Partner


                              38 NEWBURY VENTURES/MBC LIMITED PARTNERSHIP

                              By:  Samuel E. Bain Jr.
                              Its:  General Partner
                              /s/ SAMUEL E. BAIN JR.
                              By:
                              Its:

                              ALBERT S. WAXMAN

                              /s/ ALBERT S. WAXMAN
                              Albert S. Waxman
                              THE ALBERT S. WAXMAN FAMILY
                              CHARITABLE REMAINDER UNITRUST

                              /s/ ALBERT S. WAXMAN
                              By:  Albert S. Waxman
                              Its:   Trustee

                               ARTHUR H. HALPER
                               /s/ ARTHUR H. HALPER
                               Arthur H. Halper

                               MICHAEL G. LENAHAN
                               /s/ MICHAEL G. LENAHAN
                               Michael G. Lenahan

                               JOHN A. BUDNICK
                               /s/ JOHN A. BUDNICK
                               John A. Budnick


Agreed and Acknowledged:

MAGELLAN HEALTH SERVICES, INC.

/s/ CRAIG MCKNIGHT
By:  Craig McKnight
Its:  Executive Vice President/Chief Financial Officer




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