FIRST AMENDMENT TO THE
                           WARRANT PURCHASE AGREEMENT


         THIS FIRST  AMENDMENT TO THE WARRANT  PURCHASE  AGREEMENT  (this "First
Amendment")  is made as of the 17th day of June,  1997, by and between  MAGELLAN
HEALTH SERVICES, INC., a Delaware corporation (the "Company"), and CRESCENT REAL
ESTATE EQUITIES LIMITED PARTNERSHIP, a Delaware limited partnership ("Buyer").

                                                  R E C I T A L S

         A. The Company and Buyer  entered  into that certain  Warrant  Purchase
Agreement dated as of January 29, 1997 (the "Agreement"). Capitalized terms used
but not defined herein have the meanings ascribed to them in the Agreement.

         B. The parties desire to enter into this First Amendment to evidence
their agreement to certain changes to the Agreement, as hereinafter set forth.

         NOW  THEREFORE,  in  consideration  of the mutual  covenants  set forth
herein, the Company and the Buyer hereby agree as follows:

         1.       Section 1.2 is deleted in its entirety and replaced with the 
following:

                  1.2 Purchase Price and Payment. The parties hereto acknowledge
                  that the  Purchase  Price for the Warrants was made by them in
                  arm's length negotiation. The aggregate purchase price for the
                  Warrants  is Twelve  Million  Five  Hundred  Thousand  Dollars
                  ($12,500,000)  (the  "Purchase  Price").  The  Purchase  Price
                  payable by Buyer for the Warrants shall be paid by Buyer on or
                  before  Closing Date (as  hereinafter  defined) in immediately
                  available  funds by confirmed  wire transfer to a bank account
                  to be designated by the Company (such  designation to occur no
                  later than the third Business Day prior to the Closing Date).

         2.       Section 3.8 is deleted in its entirety and replaced with the 
following:

                  3.8 Rights  Plan.  Based upon the  representation  of Buyer in
                  Section 4.6 hereof and  relying  upon the  information  in the
                  most   recent   Schedule   13D  filed  by   Rainwater-Magellan
                  Holdings,L.P.  related to stock ownership in the Company,  the
                  execution  of this  Agreement  and the issuance of the Warrant
                  Shares (assuming the continued  validity of the representation
                  of Buyer in Section 4.6 hereof) shall not cause an issuance of
                  certificates within the

                                      - 1 -





                  meaning of Section 3 of the Rights  Agreement dated as of July
                  21,  1992,  as  amended  by  the  First  Amendment  to  Rights
                  Agreement  dated as of May 30,  1997,  between the Company and
                  First  Union  National  Bank of North  Carolina  (the  "Rights
                  Agreement")  or a  Triggering  Event as  defined in the Rights
                  Agreement.

         3.       The reference to "Crescent Opportunity Corporation ("COC")" in
Section 5.5 should read "Crescent Operating, Inc. ("COI")".

         4.       Section 5.12 of the Agreement is deleted in its entirety.

         5.       The definition of "Rights Agreement" contained in Section 11.1
is deleted in its entirety and replaced with the following:

                  "Rights Agreement" means that certain Rights Agreement,  dated
                  as of July 21,  1992,  as  amended by the First  Amendment  to
                  Rights  Agreement,  dated  as of May  30,  1997,  between  the
                  Company and First Union  National Bank of North  Carolina,  as
                  rights agent.

         6.       Annex I is deleted in its entirety and replace with Annex I 
attached hereto.


                                      - 2 -





         IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
executed and delivered this 17th day of June, 1997.


                               MAGELLAN HEALTH SERVICES, INC., a
                               Delaware corporation


                               By:      \s\ Linton C. Newlin
                                        -------------------------------
                               Title:   Vice President and Secretary
                                        -------------------------------



                               CRESCENT REAL ESTATE EQUITIES
                               LIMITED PARTNERSHIP, a Delaware limited
                               partnership

                               By:      Crescent Real Estate Equities,
                                        Ltd., A Delaware corporation, its sole
                                        general partner


                               By:      \s\ David M. Dean
                                        -------------------------------
                               Title:   Senior Vice President, Law
                                        -------------------------------




                                      - 3 -