Cerebellum-based Imaging Neural Markers for Antipsychotic Response

Inclusion Criteria:

* Diagnosis of a first-episode psychotic disorder including: schizophrenia, schizophreniform disorder, schizoaffective disorder, brief psychotic disorder, psychotic disorder Not Otherwise Specified (NOS), bipolar disorder with psychosis, and major depressive disorder with psychosis;
* Current positive symptoms rated \> 3 (moderate) on one or more of the Brief Psychiatric Rating Scale (BPRS) psychosis items: conceptual disorganization, grandiosity, hallucinatory behavior, and unusual thought content;
* At early phase of illness as defined by having taken antipsychotic drugs for a cumulative lifetime period of 8 weeks or less;
* Age 15 to 40;
* Competent to sign informed consent.

Exclusion Criteria:

* Serious neurological or endocrine disorder or brain trauma;
* Any medical condition which requires treatment with a medication with psychotropic effects;
* Significant risk of suicidal or homicidal behavior;
* Cognitive or language limitations, or any other factor that would preclude subjects providing informed consent;
* Contraindications to antipsychotic monotherapy;
* Contraindications to MR imaging (e.g. pacemaker);
* Pregnancy by self report.