Relationship of sedative-hypnotic response to self-injurious behavior and stereotypy by mentally retarded clients.

Groups of clients exhibiting both self-injurious behavior (SIB) and stereotypy, stereotypy alone, SIB alone, or neither of these types of behavior were rated in terms of response to sedative-hypnotic medication. Sixty-eight percent of the clients with both SIB and stereotypy maintained wakefulness and were either resistive, combative, restless, uncooperative, or abusive after treatment with sedative-hypnotics. Thirty-nine percent of the clients with only SIB and 35 percent of the clients with only stereotypy evidenced such "paradoxical" responses to these medications. None of the matched control clients displayed paradoxical responses. This result suggests that an impaired endogenous opiate system characterized by increased levels of beta-endorphin may mediate and maintain a type of syndrome of SIB that involves the presence of stereotypy, implying the need for a new diagnostic classification and treatment of these aberrant behavioral disorders.