This is a randomized, controlled pilot study comparing the antidepressant fluoxetine with the second generation antipsychotic aripiprazole in approximately 10 subjects aged 12-25 at risk for developing psychosis.

Our primary hypotheses are that compared to aripiprazole, fluoxetine will be better tolerated and will lead to greater improvement in symptoms at the end of 6 months of treatment.

Inclusion Criteria:

• 12-25 years of age (inclusive)
• Able to understand and speak English
• Have at least one sub-threshold positive psychotic symptom that is moderate, moderately severe, or severe

Exclusion Criteria:

• Lifetime diagnosis of an Axis I psychotic disorder: schizophreniform disorder; schizophrenia; schizoaffective disorder; bipolar disorder; or major depression with psychotic features
• Current psychosis
• Current diagnosis of Major Depressive Disorder, single episode or recurrent, severe without psychotic features
• Lifetime diagnosis of substance abuse or dependence (excluding nicotine)
• Current stimulant treatment
• Any significant medical condition that contra-indicates treatment with either aripiprazole or fluoxetine, including history of neurological, neuroendocrine or other medical condition known to affect the brain
• Estimated intelligence quotient < 70