<PAGE>

                                                                Exhibit 4.16



                          REGISTRATION RIGHTS AGREEMENT

      THIS REGISTRATION RIGHTS AGREEMENT (the "Agreement") is made by American
Psych Systems, Inc., a Delaware corporation (the "Company"), for the benefit of
KBL Healthcare, Inc. ("KBL") and its designees listed on Schedule I hereto.

                                    RECITALS

      A. KBL is acting as the Company's exclusive placement agent in connection
with a private offering (the "Offering") of up to an aggregate of 1,850,000
Units of the Company (the "Units"), each Unit consisting of one share of the
Company's common stock, $.001 par value (the "Common Stock"), and a warrant to
purchase one-quarter share of Common Stock, all upon the terms set forth in the
Confidential Private Placement Memorandum dated February 15, 1994 (the
"Memorandum").

      B. As part of KBL's compensation for its services as placement agent (the
"Placement Agent") in the Offering, if subscriptions to purchase at least
750,000 Units have been received from prospective investors prior to the
expiration of the Offering Period (as defined in the Memorandum) and accepted by
the Company, KBL and its designees shall receive UPOs (as defined in the
Memorandum) and Consulting Warrants (as defined in the Memorandum) in the
amounts set forth therein.

      C. As further inducement for KBL to act as Placement Agent in the
Offering, 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 Common Stock included in the
UPOs (the "UPO Shares"), the Common Stock issuable upon the exercise or
conversion of the UPO Warrants underlying the UPOs (the "UPO Warrant Shares")
and the Common Stock issuable upon the exercise or conversion of the Consulting
Warrants (the "Consulting Warrant Shares"), in accordance with the terms hereof.
<PAGE>

                                   AGREEMENTS

      The Company and KBL and its designees 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, but only if such holder or holders is KBL or a designee
of KBL 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 UPO Shares, the
UPO Warrant Shares and the Consulting Warrant 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


                                       2
<PAGE>

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 (assuming
the exercise of the UPOs, the UPO Warrants and the Consulting Warrants) to
register all or part of such holders' Registrable Securities (but not less than
twenty percent (20%) of the outstanding Registrable Securities (assuming the
exercise of the UPOs, the UPO Warrants and the Consulting Warrants)), 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 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 data of the receipt of any such registration request. Unless the
Holder or Holders of a majority in interest of the Registrable Securities
requested to be Registered (assuming the exercise of the UPOs, the UPO Warrants
and the


                                       3
<PAGE>

Consulting Warrants) shall give their written consent, no other party, including
the Company (but excluding other holders of Registrable Securities), shall be
permitted to offer securities under any such demand registration. 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 to be included in such
Registration all of the Registrable Securities that Holder has requested to be
included.


                                       4
<PAGE>

      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
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.


                                       5
<PAGE>

                  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 (assuming the exercise of the Warrants), 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


                                       6
<PAGE>

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 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 say 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 loss, liability, claim or damage at or prior to the time such
action is


                                       7
<PAGE>

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 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 alter 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 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


                                       8
<PAGE>

unless the named parties to such action or proceedings include both the
indemnifying party and the indemnified parties and the indemnifying 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 (assuming the exercise of the UPOs, the UPO Warrants and
the Consulting Warrants)). 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 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


                                       9
<PAGE>

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 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 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


                                       10
<PAGE>

Registration Statement or the initiation of any proceedings 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 (assuming the exercise of the UPOs, the UPO
Warrants and the Consulting Warrants), 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 best 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.


                                       11
<PAGE>

            (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:

                  (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, and (c) immediately following such transfer the further
disposition of such securities by the transferee or assignee is restricted under
the Act and (3) immediately following such transfer such transferee or assignee
shall hold 10,000 Registrable Securities (assuming the exercise of all UPOs, UPO
Warrants and Consulting Warrants held by such transferee or assignee).


                                       12
<PAGE>

      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, (ii) if to KBL Healthcare, Inc., at 645 Madison Avenue, 14th Floor,
New York, New York 10022, Attention: Marlene R. Krauss, M.D., Chairman and Chief
Executive Officer, and (iii) if to a Holder other than KBL, at the address set
forth under his or her name on Schedule I hereto, 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 will 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 all
respects 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 (assuming exercise of
the UPOs, the UPO Warrants and the Consulting Warrants). Any amendment or waiver
effected in accordance with this Section 4(d) shall be binding upon the Holders
and the Company.


                                       13
<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.

DATED this 20th day of March, 1994.

AMERICAN PSYCH SYSTEMS, INC.


By: /s/ Kenneth Kessler
   ---------------------------------
      Kenneth Kessler, M.D.
      President

KBL HEALTHCARE, INC.

/s/ Marlene Krauss
------------------------------------
Marlene R. Krauss, M.D.
Chairman and Chief Executive Officer

/s/ Jordan Davis
------------------------------------
Jordan S. Davis

/s/ Irene French
------------------------------------
Irene B. French

/s/ Daniel Lubin
------------------------------------
Daniel C. Lubin


                                       14