Description
The opiate hypothesis maintains that patients engage in self-injurious behavior (SIB) either because they are partially analgesic (pathologically altered pain threshold) or because SIB supplies a "fix" for an addicted endogenous opiate system. The finding that opiate antogonists attenuate SIB is the strongest evidence for the opiate hypothesis. Most of the patients who had been administered opiate receptor antagonists for treatment of self-injurious behavior also had autistic disorder. Initial studies with naloxone, an injectable opiate blocker, reported positive effects in 8 (with robust effects in 6) of the 10 patients treated. Positive results were reported in studies with orally administered naltrexone in 38 of 45 autistic patients, including 24 of those 28 with SIB. Generally, the effective dose range for naltrexone is 0.5-1.5 mg/kg, but patients with high-frequency SIB typically responded best to the higher doses. Although the findings suggest a role of opiates in SIB, the database is very small and the studies vary widely in dimensions of dose, duration and method of observation, experimental controls, duration of treatment, and the age, gender, and diagnosis of patients treated. At this time, opiate blockers appear to be the only treatment option for some SIB patients who fail to respond to other treatments. It is unclear whether these treatments would help autistic patients who do not exhibit SIB or whether they would help nonautistic patients who demonstrate SIB, including individuals with Lesch-Nyhan disease, phenylketonuria, border-line personality, or major depression.
1990