There are actually four types of situations where intervention with antipsychotics might be considered for the treatment of Obsessive compulsive disorder. Obsessive compulsive patients with poor insight (what was previously called ‘psychotic obsession’), schizophrenic patients with OCD, obsessive compulsive patients with tic disorder, and obsessive compulsive patients who did not respond to intervention with an adequate treatment of antiobsessive medication.

The data supporting the role of antipsychotic medication in obsessive compulsives with poor insight are not convincing. However, at times the treatment dilemma (antipsychotic or antiobsessive) actually derives from diagnostic ambiguity; many of the very severe ego-syntonic obsessive compulsive patients may be erroneously diagnosed as schizophrenic, while they are actually severe OCD that should be treated with antiobsessive medication and not antipsychotic.

The prevalence of OCD amongst schizophrenic patients ranges from 10-25% and has a negative effect on the prognosis for those substantial proportion of schizophrenic patients. Preliminary data implies that for this subset of patient (the schizo-obsessive patients) a combination of antipsychotic and antiobsessive medication might be useful.

It is crucial to screen for tic disorder in patients with, OCD as this subset of patients responds (both in terms of obsession and tics) to a combination of typical antipsychotic and antiobsessive medication.

Data in regard to augmentation of OCD patients who did not respond to treatment with SSRI suggest that risperidone might have a specific therapeutic potential in this subset of patients. The role of antipsychotics with 5HT1D properties like ziprasidone need to be studied.