POWER OF ATTORNEY


      I, the undersigned, hereby authorize and designate Anne Marie
Cook (SVP, General Counsel), Erin Lanciani (SVP, People and
Organizational Strategy), and Jennifer Fitzpatrick (Vice President,
Corporate Counsel) for as long as they remain employees of Sage
Therapeutics, Inc., and Laurie Burlingame of Goodwin Procter, each
acting singly, or their successors in role, to take the following
actions, acting as my agent and attorney-in-fact, with full power of
substitution:

          (1)  to prepare and sign on my behalf any Form 3, Form 4 or
Form 5 pursuant to Section 16 of the Securities Exchange Act of 1934,
as amended, and to file the same with the Securities and Exchange
Commission, NASDAQ, NYSE, and each stock exchange on which shares of
Common Stock or other securities of Sage Therapeutics, Inc. are
listed, as required by law;

          (2)  to prepare and sign on my behalf any Form 144
pursuant to the Securities Act of 1933, as amended, and to file the
same with the Securities and Exchange Commission, NASDAQ, NYSE, and
each stock exchange on which shares of Common Stock or other
securities of Sage Therapeutics, Inc. are listed, as required by law;
and

          (3)  take any other action necessary or proper in
connection with the foregoing.

      Unless earlier revoked under the next sentence, this Power of
Attorney shall remain in effect as long as I am an executive officer
or director of Sage Therapeutics, Inc., and shall not be affected by
my subsequent disability or incompetence.  I may revoke this Power of
Attorney by written notice delivered, in person or by nationally
recognized courier, to the attention of the SVP, General Counsel of
Sage Therapeutics, Inc.



                    /s/ Kimi Iguchi
		    ___________________________________________________
                    (Signature of Executive Officer or Director)


                    Name:  Kimi Iguchi, Chief Financial Officer

                    Date:    1/23/2019