LIMITED POWER OF ATTORNEY

The undersigned hereby constitutes and appoints each of
Anne Marie Cook, Kimi Iguchi and Laurie A. Burlingame
and each of them individually, and with full power of
substitution, the undersigned's true and lawful
attorney-in-fact to:

(1) Complete and execute for and on behalf
of the undersigned, in the undersigned's capacity as
an officer, director and/or ten percent (10%) shareholder
of Sage Therapeutics, Inc., a Delaware corporation
(the "Company") any and all instruments, certificates
and documents required to be executed on behalf of the
undersigned as an individual or on behalf of the
undersigned's company or partnership, as
the case may be, pursuant to Section 13 and Section 16
of the Securities Exchange Act of 1934, as amended
(the  "Exchange Act")or the rules and regulations
thereunder;

(2)Do and perform any and all acts for and on behalf of
the undersigned which may be necessary or desirable to
complete and execute any such instruments, certificates
or documents required to be filed pursuant to Sections
13 and 16 of the Exchange Act or the rules or
regulations thereunder and timely file such forms
with the United States Securities and Exchange Commission
and any stock exchange or similar authority; and

(3)Take any other action of any type whatsoever
in connection with the foregoing which, in the opinion
of such attorney-in-fact, may be of benefit to, in the
bestinterest of, or legally required by, the
undersigned,it being understood that the documents
executed by any such attorney-in-fact on behalf of the
undersigned pursuant to this Power of Attorney shall be
in such form and shall contain such
terms and conditions as such attorney-in-fact may
approve in such attorney-in-fact's discretion.

The undersigned hereby grants to each such attorney-in-fact,
acting singly, full power and authority to do and perform
any and every act which is necessary, proper or desirable
to be done in the exercise of any of the rights and powers
herein granted, as fully to all intents and purposes as
the undersigned might or could do if personally present,
with full power of substitution or revocation, hereby
ratifying and confirming all that any such attorney-in-fact,
or any such attorney-in-fact's substitute or substitutes,
shall lawfully do or cause to be done by virtue of this
Power of Attorney and the rights and powers herein granted.

The undersigned acknowledges that each of the foregoing
attorneys-in-fact, in serving in such capacity at the request
of the undersigned, are not assuming, nor is the Company
assuming, any of the undersigned's responsibilities to comply
with Section 13 or Section 16 of the Exchange Act or the
rules or regulations thereunder.  The undersigned hereby
agrees to indemnify each attorney-in-fact and the Company
from and against any demand, damage, loss, cost or expense
arising from any false or misleading information provided
by the undersigned to such attorney-in fact.

This Power of Attorney shall remain in full force and effect
until the undersigned is no longer required to file any
instruments, certificates and documents pursuant to
Section 13 and 16 of the Exchange Act or the rules or
regulations thereunder with respect to the undersigned's
holdings of and transactions in securities issued by
the Company, unless earlier revoked by the undersigned i
in a signed writing delivered to the foregoing
attorneys-in-fact.

IN WITNESS WHEREOF, the undersigned has caused
this Power of Attorney to be executed as of April 25, 2017.


                    /s/ Michael Cloonan
                   ________________________________________________
                    (Signature of Executive Officer or Director)