Schizophrenia is a mental disorder that alters perception, thinking, social functioning and attention. Symptoms are usually subdivided into positive symptoms and negative symptoms. Positive symptoms include delusions, hallucinations, and disorganized speech and behavior. Negative symptoms include apathy and social withdrawal.

The causes of schizophrenia are unknown, although there appears to be a strong genetic component. There are brain abnormalities in both the frontal lobes (critical for abstract thought and judgment) and in the hippocampus (critical for memory).

Schizophrenic symptoms usually first arise when the individual is between the late teens and late twenties. Treatment focuses on alleviating symptoms, and medications which control the symptoms tend to have severe side effects. Nonetheless, many schizophrenic individuals manage to lead independent lives as long as they remain medicated.