In patients stabilized on their antipsychotic and demonstrating evidence of good clinical response, there will not be a significant change in symptoms if their medication is decreased to every 2 days rather than daily. This decrease in antipsychotic exposure will lead to a reduction in side effects, as well as improved subjective response to treatment.

The present study is a 6-month, double-blind study of patients with schizophrenia stabilized on their current antipsychotic (monotherapy) for a period of at least 3 months. After providing informed consent, individuals will be randomly assigned to 1 of 2 treatment arms: regular daily antipsychotic dosing or active medication at the same daily dose every 2nd day. Various scales to measure clinical response and side effects will be administered at baseline, as well as every 2 weeks thereafter. Subjective scales will also be employed, and lab evaluations will include plasma antipsychotic levels at baseline and endpoint, as well as prolactin. Our sample size will be 20/group.

Inclusion Criteria:

• DSM-IV diagnosis of schizophrenia or schizo-affective disorder
• Capacity to provide written, informed consent
• Stabilized* on a single oral antipsychotic for at least three months (excluding CLOZAPINE or QUETIAPINE)
• Evidence of compliance with previous antipsychotic treatment, i.e. greater than 90% * defined as 2 consecutively identical CGI evaluations (screening and baseline, at least one week apart)

Exclusion Criteria:

• exposure to depot antipsychotic during 12 months prior to enrollment
• substance-related disorders according to DSM-IV