People have tried to understand mental illness for thousands of years. The causes of schizophrenia are still not clear, but scientists believe several things may be involved. Schizophrenia can run in families. The environment may also play a role in terms of stressful surroundings, illnesses, and poor nutrition. Disruptions in brain development may also be a risk factor.

Schizophrenia is usually diagnosed between the late teens and early thirties. It tends to appear earlier in males (late teens-early twenties) than in females (early twenties – early thirties). Schizophrenia is a lifelong condition.