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                                                                  Exhibit 4.15



                          REGISTRATION RIGHTS AGREEMENT

      THIS REGISTRATION RIGHTS AGREEMENT (the "Agreement") is made this 3rd day
of February, 1995 by American Psych Systems, Inc., a Delaware corporation (the
"Company"), for the benefit of the investors listed on Schedule I hereto
(collectively, the "Investors," individually an "Investor").

                                    RECITALS

      A. The Investors desire to purchase from the Company, and the Company
desires to issue and sell to the Investors, up to an aggregate of 3,000,000
shares (the "Shares") of the Company's common stock, $.001 par value (the
"Common Stock"), upon the terms set forth in the Confidential Private Placement
Memorandum dated October 3, 1994, as supplemented (the "Memorandum").

      B. As further inducement for the Investors to purchase the Common Stock
from the Company, the Company has agreed to provide certain registration rights
under the Securities Act of 1933, as amended, and the rules and regulations
thereunder (collectively, the "Act"), with respect to the Shares, and in
accordance with, the terms and conditions set forth in this Agreement.

                                   AGREEMENTS

      The Company and the Investors covenant and agree as follows:

      1.    REGISTRATION RIGHTS.

            1.1   CERTAIN DEFINITIONS.

            As used in this Agreement, the following terms shall have the
following respective meanings:

                  (a) "COMMISSION" shall mean the Securities and Exchange
Commission or any other federal agency at the time administering the Act.

                  (b) "FORM S-3" shall mean Form S-3 issued by the Commission or
any substantially similar form then in effect.

                  (c) "HOLDER" shall mean, individually, any holder of
outstanding Registrable Securities and collectively, the holders of outstanding
Registrable Securities,

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but only if such holder or holders is an Investor or an assignee or
transferee of registration rights as permitted by Section 3.

                  (d) The terms "REGISTER", "REGISTERED" and "REGISTRATION"
refer to a registration effected by preparing and filing a registration
statement in compliance with the Act ("Registration Statement"), and the
declaration or ordering by the Commission of the effectiveness of such
Registration Statement.

                  (e) "REGISTRABLE SECURITIES" shall mean the Shares, so long as
certificates representing the same are required to bear the restrictive legend
set forth in Section B(10) of the Subscription Agreement.

                  (f) "REGISTRATION EXPENSES" shall mean all expenses incurred
by the Company in complying with Section 1, including, without limitation, all
federal and state registration, qualification and filing fees, printing
expenses, fees and disbursements of counsel for the Company, blue sky fees and
expenses, and the expense of any special audits incident to or required by any
such Registration.

                  (g) "RESTRICTION TERMINATION DATE" shall mean, with respect to
any Registrable Securities, the date on which the Company shall have notified
the Holder of such Registrable Securities in writing that it has determined that
such Registrable Securities may be sold pursuant to Rule 144 (or any successor
provision) without restriction under Rule 144(e) thereof, and, based upon such
determination, the legend shall have been removed.

                  (h) "SELLING EXPENSES" shall mean all underwriting discounts
and selling commissions applicable to the sale of Registrable Securities
pursuant to this Agreement.

            Capitalized terms used but not defined herein shall have the
meanings set forth in the Memorandum.

            1.2   REQUEST FOR REGISTRATION

                  1.2.1 REQUEST AND FILING. If the Company shall receive a
written request from one or more holders of Registrable Securities holding at
least twenty percent (20%) of the outstanding Registrable Securities to register
all or part of such holders' Registrable Securities (but not less than twenty
percent (20%) of the outstanding Registrable Securities), the Company shall, as
promptly as practicable, but in no event later than ninety (90) days after the
date on which the request for registration was given to the Company, prepare and
file with the Commission a Registration Statement sufficient to permit the
public offering and sale of such Registrable Securities and the Registrable
Securities of any other Holders who notify the Company within ten (10) days
after receiving notice from the Company of such request, and will use its best
efforts through its officers, directors, auditors and counsel to cause such
Registration Statement to become effective as promptly as practicable and

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to maintain the effectiveness thereof for at least nine months; PROVIDED,
HOWEVER, that the Company shall not be obligated to file such a Registration
Statement covering the Registrable Securities until twelve months following
the completion of its initial public offering and, PROVIDED, FURTHER, that
the Company shall only be obligated to file one demand Registration Statement
for which all Registration Expenses incurred in connection with such
Registration shall be borne by the Company. The Company covenants and agrees
to give written notice of any registration request under this Section 1.2 by
any Holder or Holders to all other holders of Registrable Securities within
ten (10) days from the date of the receipt of any such registration request.
Other parties, including the Company, shall be permitted to offer securities
under any such demand registration without the consent of the Holders of the
Registrable Securities, PROVIDED, HOWEVER, that any reduction of the amount
of securities to be included in such offering shall first come from the
securities intended to be offered by parties other than the Holders of
Registrable Securities. A Registration Statement will not count as the one
required demand Registration Statement until it has become effective. In
addition to the foregoing, at such time as it becomes eligible to do so the
Company shall file a Registration Statement covering all of the Registrable
Securities eligible to be registered on such Form on Form S-3, and shall use
its best efforts to cause such Registration Statement to become effective as
promptly as practicable, and to maintain the effectiveness thereof until the
Restriction Termination Date. Notwithstanding the foregoing, the Company
shall have no obligation to comply with the foregoing provisions of this
Section 1.2 if, in the opinion of counsel to the Company reasonably
acceptable to the person or persons from whom, or on whose behalf, such
written request has been received, registration under the Act is not required
for the transfer of the Registrable Securities in the amount and manner
proposed by such person or persons.

                  1.2.2 UNDERWRITTEN OFFERING. If (but without any obligation to
do so) the Registrable Securities are included in an underwritten offering, the
Company and the Holders of Registrable Securities shall enter into an
underwriting agreement in customary form with the managing underwriter or
underwriters selected for such underwriting by the Company.

            1.3 COMPANY REGISTRATION. If (but without any obligation to do so)
the Company proposes to Register at any time prior to the Restriction
Termination Date (including for this purpose a Registration effected by the
Company for stockholders other than the Holders) any of its stock or other
securities under the Act in connection with the underwritten public offering of
such securities solely for cash (other than a Registration of securities in
connection with mergers, acquisitions, exchange offers, distributions to the
Company's stockholders, or stock option or other employee benefit plans or a
Registration in any form which does not include substantially the same
information as would be required to be included in a registration statement
covering the sale of the Registrable Securities), the Company shall, at each
such time, promptly give the Holders written notice of such Registration. Upon
the written request of a Holder given within fifteen (15) days after mailing of
such notice by the Company, the Company shall, subject to the following
provisions, use all reasonable efforts to cause

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to be included in such Registration all of the Registrable Securities that
Holder has requested to be included.

      The Company shall not be required under this Section 1.3 to include any
of a Holder's securities in an underwritten offering of the Company's
securities if it is not permitted to do so pursuant to the Registration
Rights Agreements, dated as of March 30, 1994, made by the Company for the
benefit of investors and the placement agent and its designees relating to
the offering of up to an aggregate of 1,850,000 Units of the Company and
unless such Holder accepts the terms of the underwriting as agreed upon
between the Company and the underwriters selected by it, and then only in
such quantity as will not, in the opinion of the managing underwriters,
interfere with the successful marketing of the offering by the Company;
PROVIDED, HOWEVER, that any reduction of the amount of securities to be
included in such offering shall not represent a greater fraction of the
number of securities intended to be offered by holders of Registrable
Securities than the fraction of similar reductions imposed on such other
persons or entities (but not the Company) with respect to the amount of
securities they intended to offer in such offering.

            1.4 BLUE SKY. In the event of any Registration pursuant to this
Agreement, the Company will exercise its best efforts to Register and qualify
the Registrable Securities covered by the Registration Statement under such
other securities or Blue Sky laws of such jurisdictions as shall be reasonably
requested by the Holders for the distribution of such securities; PROVIDED,
HOWEVER, that the Company shall not be required to qualify to do business, to
file a general consent to service of process or to subject itself to taxation in
any state or jurisdiction in which it is not now qualified. The Company will
furnish to the Holders written advice of its counsel with respect to
registration or exemption of such Registrable Securities in such jurisdictions.

            1.5 EXPENSES OF REGISTRATION. All Registration Expenses incurred in
connection with a Registration pursuant to this Agreement shall be borne by the
Company. All Selling Expenses shall be borne by the Holders.

            1.6   REGISTRATION PROCEDURES.

                  1.6.1 ADVICE BY COMPANY. The Company will keep each Holder
advised as to the initiation and completion of such Registration. At its expense
the Company will (i) use its best efforts to keep such Registration effective
until nine months after the effective date of the Registration Statement in the
case of a Registration on other than a Form S-3 and, in the case of any other
Registration, on the earlier of (a) the date on which the Holders have completed
the distribution described in the Registration Statement or (b) the Restriction
Termination Date with respect to such securities; and (ii) furnish such number
of prospectuses (including preliminary prospectuses) and other documents as the
Holders from time to time may reasonably request.

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                  1.6.2 AMENDMENTS. The Company will promptly prepare and file
with the Commission such amendments and prospectus supplements, including
post-effective amendments, to the Registration Statement as the Company
determines may be necessary or appropriate, and use its best efforts to have
such post-effective amendments declared effective as promptly as practicable;
cause the related prospectus to be supplemented by any prospectus supplement,
and as so supplemented, to be filed with the Commission; and notify the Holders
of any securities included in such Registration Statement and the underwriter
thereof, if any, promptly when a prospectus, any prospectus supplement or
post-effective amendment must be filed or has been filed and, with respect to
any post-effective amendment, when the same has become effective.

                  1.6.3 UNDERWRITTEN OFFERINGS. In connection with an
underwritten offering in which the Registrable Securities are included, at
the request of the Holders owning a majority in interest of the Registrable
Securities requested to be sold, on the date that such Registrable Securities
are delivered to the underwriters for sale pursuant to such Registration in
an underwritten offering, the Company will (a) furnish (i) an opinion, dated
as of such date, of the independent counsel representing the Company for the
purposes of such Registration, addressed to the underwriter, in a customary
form and covering matters of the type customarily covered in such legal
opinions; and (ii) a comfort letter dated as of such date, from the
independent certified public accountants of the Company addressed to the
underwriter in a customary form and covering matters of the type customarily
covered by such comfort letters; such opinion of counsel shall additionally
cover such other legal matters with respect to the Registration in respect of
which such opinion is being given as such underwriter may reasonably request
and such letter from the independent certified public accountants shall
additionally cover such other financial matters (including information as to
the period ending not more than five business days prior to the date of such
letter) with respect to the Registration in respect of which such letter is
being given as such underwriter may reasonably request; and (b) with such
Holders, enter into customary agreements (including an underwriting agreement
in customary form) and take such other actions as are reasonably required in
order to expedite or facilitate the disposition of such Registrable
Securities.

            1.7 INFORMATION FURNISHED BY HOLDER. It shall be a condition
precedent to the Company's obligations under this Agreement as to any holder
that each Holder furnish to the Company in writing such information regarding
such Holder and the distribution proposed by such Holder as the Company may
reasonably request.

            1.8   INDEMNIFICATION.

                  1.8.1 COMPANY'S INDEMNIFICATION OF HOLDERS. The Company will
indemnify each Holder, each of its officers, directors and partners, and each
person controlling such Holder within the meaning of Section 15 of the Act or
Section 20(a) of the Securities Exchange Act of 1934, as amended (the "Exchange
Act"), with respect to which Registration, qualification or compliance of
Registrable Securities has been

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effected pursuant to this Agreement, and each underwriter, if any, and each
of its officers, directors, constituent partners, and each person who
controls any underwriter against all claims, losses, damages or liabilities
(or actions in respect thereof) to the extent such claims, losses, damages or
liabilities arise out of or are based upon any untrue statement (or alleged
untrue statement) of a material fact contained in any prospectus or any
related Registration Statement incident to any such Registration,
qualification or compliance, or any omission (or alleged omission) to state
therein a material fact required to be stated therein or necessary to make
the statements therein not misleading, or any violation by the Company of any
rule or regulation promulgated under the Act applicable to the Company and
relating to action or inaction required of the Company in connection with any
such Registration; and the Company will reimburse each such Holder, each such
underwriter and each person who controls any such Holder or underwriter, for
any legal and any other expenses reasonably incurred in connection with
investigating or defending any such claim, loss, damage, liability or action;
PROVIDED, HOWEVER, that the indemnity contained in this Section 1.8.1 shall
not apply to amounts paid in settlement of any such claim, loss, damage,
liability or action if settlement is effected without the consent of the
Company (which consent shall not unreasonably be withheld or delayed); and
PROVIDED, FURTHER, that the Company will not be liable in any such case to
the extent that any such claim, loss, damage, liability or expense arises out
of or is based upon any untrue statement or omission based upon written
information furnished to the Company by such Holder, underwriter or
controlling person for use in connection with the offering of securities of
the Company. Notwithstanding the above, the foregoing indemnity agreement is
subject to the condition that, insofar as it relates to any such untrue
statement, alleged untrue statement, omission or alleged omission made in a
preliminary prospectus, such indemnity agreement shall not inure to the
benefit of any underwriter or any Holder, if there is no underwriter, if a
copy of the final prospectus was not furnished to the person asserting the
lose, liability, claim or damage at or prior to the time such action is
required by the Act if the final prospectus corrected the untrue statement or
omission or alleged untrue statement or omission.

                  1.8.2 HOLDERS' INDEMNIFICATION OF COMPANY. Each Holder will,
if Registrable Securities held by such Holder are included in the securities as
to which a Registration is being effected pursuant to this Agreement, indemnify
the Company, each of its directors and officers, each underwriter, if any, of
the Company's securities covered by such a Registration Statement, each person
who controls the Company or such underwriter within the meaning of Section 15 of
the Act or Section 20(a) of the Exchange Act, and each other Holder, its
officers, directors, constituent partners and each person controlling such other
Holders, against all claims, losses, damages and liabilities (or actions in
respect thereof) arising out of or based upon any untrue statement (or alleged
untrue statement) of a material fact contained in any such Registration
Statement or related prospectus, or any omission (or alleged omission) to state
therein a material fact required to be stated therein or necessary to make the
statements therein not misleading; and will reimburse the Company, each other
Holder, such directors, officers, partners, persons, underwriters or control
persons for any legal and any other expenses reasonably incurred in connection
with investigating or

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defending any such claim, loss, damage, liability or action, in each case to
the extent, but only to the extent, that such untrue statement (or alleged
untrue statement) or omission (or alleged omission) is made in such
Registration Statement or prospectus in reliance upon and in conformity with
written information furnished to the Company by such Holder and stated to be
specifically for use in connection with the offering of securities of the
Company; PROVIDED, HOWEVER, that each Holder's liability under this Section
1.8.2 shall not exceed such Holder's proceeds from the offering of
Registrable Securities made in connection with such Registration.

                  1.8.3 INDEMNIFICATION PROCEDURE. Promptly after receipt by
an indemnified party under this Section 1.8 of notice of the commencement of
any action, such indemnified party will, if a claim in respect thereof is to
be made against an indemnifying party under this Section 1.8, notify the
indemnifying party in writing of the commencement thereof and generally
summarize such action. The indemnifying party shall have the right to
participate in and to assume the defense of such claim and shall be entitled
to select counsel for the defense of such claim with the approval of any
parties entitled to indemnification, which approval shall not be unreasonably
withheld. Notwithstanding the foregoing, the parties entitled to
indemnification shall have the right to employ separate counsel (reasonably
satisfactory to the indemnifying party) to participate in the defense
thereof, but the fees and expenses of such counsel shall be the expense of
such indemnified parties unless the named parties to such action or
proceeding include both the indemnifying party and the indemnified parties
and the indemnified party or such indemnified parties shall have been advised
by counsel that there are one or more legal defenses available to it which
are different from or additional to those available to the indemnifying party
(in which case, if the indemnified party notifies the indemnifying party in
writing that it elects to employ separate counsel at the reasonable expense
of the indemnifying party, the indemnifying party shall not have the right to
assume the defense of such action or proceeding on behalf of the indemnified
party, as the case may be, it being understood, however, that the
indemnifying party shall not, in connection with any such action or
proceeding or separate or substantially similar or related action or
proceeding in the same jurisdiction arising out of the same general
allegations or circumstances, be liable for the reasonable fees and expenses
of more than one separate counsel at any time for the indemnifying party and
all indemnified parties, which counsel shall be designated in writing by the
Holders owning a majority in interest of the Registrable Securities
participating in the offering of securities. If the indemnifying party
withholds consent to a settlement or proposed settlement by the indemnified
party, it shall acknowledge to the indemnified party its indemnification
obligations hereunder.

                  1.8.4 CONTRIBUTION. If the indemnification provided for in
this Section 1.8 from an indemnifying party is unavailable to an indemnified
party hereunder in respect to any losses, claims, damages, liabilities or
expenses referred to herein, then the indemnifying party, in lieu of
indemnifying such indemnified party, shall contribute to the amount paid or
payable by such indemnified party as a result of such losses, claims, damages,
liabilities or expenses in such proportion as is appropriate to reflect the
relative fault of the indemnifying party and indemnified party

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in connection with the statements or omissions which result in such losses,
claims, damages, liabilities or expenses, as well as any other relevant
equitable considerations. The relative fault of such indemnifying party and
indemnified party shall be determined by reference to, among other things,
whether the untrue or alleged untrue statement of a material fact or the
omission or alleged omission to state a material fact relates to information
supplied by such indemnifying party or indemnified party and the parties'
relative intent, knowledge, access to information supplied by such
indemnifying party or indemnified party and opportunity to correct or prevent
such statement or omission, The amount paid or payable by a party as a result
of the losses, claims, damages, liabilities and expenses referred to above
shall deemed to include any legal or other fees or expenses reasonably
incurred by such party in connection with investigating or defending any
action, suit, proceeding or claim. In no event shall the amount of any such
contribution payable by a Holder exceed the amount payable by that Holder
under Section 1.8.2 hereunder.

            1.9 NO-ACTION LETTER OR OPINION OF COUNSEL IN LIEU OF REGISTRATION.
Notwithstanding anything else in this Agreement, if the Company shall have
obtained from the Commission a "no-action" letter in which the Commission has
indicated that it will take no action if, without Registration under the Act,
any Holder disposes of Registrable Securities covered by any request for
Registration made under this Section in the specific manner in which such Holder
proposes to dispose of the Registrable Securities included in such request
(including, without limitation, inclusion of such Registrable Securities in an
underwriting initiated by the Company, or if in the opinion of counsel for the
Company concurred in by counsel for the Holders, which concurrence shall not be
unreasonably withheld, no Registration under the Act is required in connection
with such disposition, the Registrable Securities included in such request shall
not be eligible for Registration under this Agreement; PROVIDED, HOWEVER, that
any Registrable Securities not so disposed of shall be eligible for Registration
in accordance with the terms of this Agreement with respect to other proposed
dispositions to which this Section 1.9 does not apply. In addition, the
obligation of the Company to file or maintain the effectiveness of any
Registration Statement under this Section 1 shall be suspended with respect to
any Registrable Securities held by a Holder at any time following the
Restriction Termination Date with respect to such Registrable Securities.

      2.    COVENANTS OF THE COMPANY. In connection with the Registration of
the Registrable Securities pursuant to this Agreement, the Company agrees to:

            (a) Notify each Holder, at any time when a prospectus relating to
Registrable Securities covered by the Registration Statement is required to be
delivered under the Act, of the happening of any event as a result of which the
prospectus included in the Registration Statement, as then in effect, includes
an untrue statement of a material fact or omits to state a material fact
required to be stated therein or necessary to make the statements therein not
misleading in light of the circumstances then existing. The Company shall use
its best efforts to promptly amend

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or supplement the Registration Statement to correct any such untrue statement
or omission.

            (b) Notify each Holder who holds Registrable Securities being sold
(or in the event of an underwritten offering, the managing underwriters) of the
issuance by the Commission of any stop order suspending the effectiveness of the
Registration Statement or the initiation of any proceeding for that purpose. The
Company will make every reasonable effort to prevent the issuance of any stop
order and, if any stop order is issued, to obtain the lifting thereof at the
earliest possible time.

            (c) Permit a single firm of counsel, designated as selling
shareholders' counsel by the holders of a majority in interest of the
Registrable Securities being sold, to review the Registration Statement and all
amendments and supplements thereto a reasonable period of time prior to their
filing, and shall not file any document in a form to which such counsel
reasonably objects.

            (d) Make available for inspection by any Holder, any underwriters
participating in the offering pursuant to the Registration Statement and the
counsel, accountants or other agents retained by any Holder or any such
underwriter, all pertinent financial and other records, corporate documents and
properties of the Company, and cause the Company's officers, directors and
employees to supply all information reasonably requested by a Holder or any such
underwriters in connection with the Registration Statement.

            (e) If the Common Stock is then listed on a national securities
exchange, use its beet efforts to cause the Registrable Securities to be listed
on such exchange if the listing of such Registrable Securities is then permitted
under the rules of such exchange, or if the Common Stock is not then listed on a
national securities exchange, use its best efforts to facilitate the quotation
of the Common Stock on NASDAQ.

            (f) Take all actions reasonably necessary to facilitate the timely
preparation and delivery of certificates (not bearing any restrictive legend)
representing the Registrable Securities to be sold pursuant to the Registration
Statement and to enable such certificates to be in such denominations and
registered in such names as the Holders or any underwriters may reasonably
request.

            (g) Take all other actions reasonably necessary to expedite and
facilitate disposition by the Holders of the Registrable Securities pursuant to
the Registration Statement.

            (h) With a view to making available to the Holders the benefits of
Rule 144 promulgated under the Act and any other rule or regulation of the
Commission that may at any time permit the Holders to sell securities of the
Company to the public without registration, the Company agrees to:

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                  (i) make and keep public information available, as those terms
      are understood and defined in Rule 144, at all times after 90 days after
      the effective date of the first registration statement filed by the
      Company for the offering of its securities to the general public;

                  (ii) file with the Commission in a timely manner all reports
      and other documents required of the Company under the Securities Act and
      the Exchange Act;

                  (iii) furnish to each Holder, so long as such Holder owns any
      Registrable Securities, forthwith upon request (a) a written statement by
      the Company that it has complied with the reporting requirements of Rule
      144, the Act and the Exchange Act (at any time after it has become subject
      to such reporting requirements), (b) a copy of the most recent annual or
      quarterly report of the Company and such other reports and documents so
      filed by the Company and (c) such other information as may be reasonably
      requested in availing the Holders of any rule or regulation of the
      Commission which permits the selling of any such securities without
      registration.

      3. ASSIGNMENT OF REGISTRATION RIGHTS. The right to cause the Company to
Register Registrable Securities pursuant to this Agreement shall be
automatically assigned by the Holders to transferees or assignees of such
securities; PROVIDED, that (a) the Company is, within a reasonable time after
such transfer, furnished written notice of (i) the name and address of such
transferee or assignee and (ii) the securities with respect to which such
registration rights are being assigned, (b) such assignment is in accordance
with and permitted by all other agreements between the transferor or assignor
and the Company, (c) immediately following such transfer the further disposition
of such securities by the transferee or assignee is restricted under the Act,
and (d) immediately following such transfer such transferee or assignee shall
hold 10,000 Registrable Securities.

      4.    MISCELLANEOUS.

            (a) Notices required or permitted to be given hereunder shall be in
writing and shall be deemed to be sufficiently given when personally delivered
or sent by registered mail, return receipt requested, addressed (i) if to the
Company, at American Psych Systems, Inc., One Democracy Plaza, 6701 Democracy
Boulevard, Suite 410, Bethesda, Maryland 20817 Attention: Kenneth Kessler, M.D.,
President, and (ii) if to a Holder, at the address set forth under his or her
name in the subscription agreement executed by such Holder in connection with
its investment, or at such other address as each such party furnishes by notice
given in accordance with this Section 4(a).

             (b) Failure of any party to exercise any right or remedy under
this Agreement or otherwise, or delay by a party in exercising such right or
remedy, will not operate as a waiver thereof. No waiver shall be effective
unless and until it is in writing and signed by the party giving the waiver.

             (c) This Agreement shall be enforced, governed and construed in
accordance with the laws of the State of Delaware. In the event that any
provision of this Agreement is invalid or unenforceable under any applicable
statute or rule of law, then such provision shall be deemed inoperative to
the extent that it may conflict therewith and shall be deemed modified to
conform with such statute or rule of law. Any provision hereof which may
prove invalid or unenforceable under any law shall not affect the validity or
enforceability of any other provision hereof.

            (d) This Agreement constitutes the entire agreement between the
parties hereto with respect to the subject matter hereof. Any provision of this
Agreement may be amended and the observance thereof may be waived (either
generally or in a particular instance and either retroactively or
prospectively), only by a writing executed by the Company and Holders who the
hold a majority in interest of the Registrable Securities. Any amendment or
waiver effected in accordance with this Section 4(d) shall be binding upon the
Holders and the Company.

<PAGE>

            (e) A person or entity is deemed to be a holder of Registrable
Securities whenever such person or entity owns of record such Registrable
Securities. If the Company receives conflicting instructions, notices or
elections from two or more persons or entities with respect to the same
Registrable Securities, the Company shall be entitled to act upon the basis of
instructions, notice or election received from registered owner of such
Registrable Securities.

                                        AMERICAN. PSYCH SYSTEMS, INC.


                                        By: /s/ Kenneth Kessler
                                           -----------------------------------
                                           Name:  Kenneth A. Kessler, MD
                                           Title: President & CEO

                                        INVESTORS

                                        KBL HEALTHCARE, INC.
                                          As Attorney-in-Fact for the
                                          Investors Listed on Schedule I


                                        By: /s/ Marlene Krauss
                                           -----------------------------------
                                          Name:  Marlene Krause, M.D.
                                          Title: Chairperson


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