EXHIBIT.23.3
 
INDEPENDENT AUDITORS' CONSENT
 
    We consent to the incorporation by reference in this Registration Statement
of Magellan Health Services, Inc. on Form S-3, to be filed on or about May 21,
1998, of our report dated November 14, 1997, appearing in the Current Report on
Form 8-K/A of Magellan Health Services, Inc., filed on April 3, 1998. Such
report expresses an unqualified opinion on the consolidated balance sheets of
Merit Behavioral Care Corporation (the "Company") as of September 30, 1997 and
1996, and the related consolidated statements of operations, stockholders'
equity, and cash flows for each of the three years in the period ended September
30, 1997 and includes an explanatory paragraph relating to the fact that
effective October 1, 1995, the Company changed its method of accounting for
deferred contract start-up costs related to new contracts or expansion of
existing contracts.
 
    We also consent to the reference to us under the heading "Experts" in the
Prospectus, which is part of this Registration Statement.
 
/s/ DELOITTE & TOUCHE LLP
New York, New York
May 21, 1998