EXHIBIT 23(A)
 
                   CONSENT OF INDEPENDENT PUBLIC ACCOUNTANTS
 
    As independent public accountants, we hereby consent to the use of our
report dated November 14, 1997 on the audited consolidated financial statements
and schedule of Magellan Health Services, Inc. and subsidiaries and to all
references to our Firm included in or made a part of this Registration
Statement.
 
                                          /s/ ARTHUR ANDERSEN LLP
 
Atlanta, Georgia
March 30, 1998