Olanzapine for chronic, stereotypic self-injurious behaviour: a pilot study in seven adults with intellectual disability

Dopamine one (DI) receptor supersensitvity in the corpus striatum is said t o be the primary mechanism within the dopamine model proposed for chronic, refractory self-injurious behaviour (SIB), which may explain why convention al neuroleptics have proven largely ineffective. In common with other atypi cal antipsychotic agents, olanzapine has more affinity for the DI receptor. The present study explored whether olanzapine could reduce rates of the st ereotypic form of chronic SIB, a subtype where dopamine dysfunction is the most likely underlying mechanism. A clinical sample of seven patients with various levels of learning disability who displayed features of stereotypic SIE were assessed over a 6-week period of baseline measurement and a 15-we ek treatment phase during which olanzapine was added to existing medication . Both SIE and other aberrant behaviours were measured by daily nurse ratin g and the Self-injury Trauma Scale (SITS). All measurements were unblind. D oses ranged from 5 to 15 mg. Out of the seven subjects, three showed a clea r improvement, one showed a marginal improvement, one deteriorated, and the data was equivocal for the remaining two individuals. The means of the SIT S Number and Severity Indices (NI and SI, respectively) reduced significant ly from baseline during both the 5- and 10-mg treatment phases, and taking treatment as a whole, by 53% and 48%, respectively (NI mean = 0.7 units red uction, P= 0.02; SI: mean = 0.9 units reduction, P= 0.04). The risk index a lso reduced, but did not reach significance. A modest reduction in mean nur se-rated SIE was not significant for either phase or for treatment as a who le. At doses above 5 mg, mean scores deteriorated on balance, although two responders showed a marginal additional improvement. Olanzapine was well to lerated with one adverse event reported (somnolence) which was mild and tra nsient. The present pilot study suggests that olanzapine can reduce stereot ypic SIE. A larger trial is indicated.