Obsessive-compulsive symptoms with olanzapine.

The emergence or exacerbation of obsessive-compulsive (OC) symptoms during treatment with atypical antipsychotics, mostly clozapine, has been documented by numerous case reports (reviewed by Lykouras et al., 2003). In six recent reports involving nine cases, (Jonkers and de Haan, 2002; Lykouras et al., 2003) olanzapine was found either to cause de novo emergence or to exacerbate OC symptoms. In six of these cases olanzapine caused exacerbation and in three cases caused de novo emergence of OC symptoms.