Schizophrenia usually develops in the teens or early adulthood. When the illness first attacks a person, there are changes experienced by him/her or observed by his/her relatives.

These changes may be gradual for some people and sudden and acute for others. The changes may include trouble sleeping, suspicion, fear, and decrease in general functioning (e.g. having problems in studying, keeping a job, taking care of themselves and relating with others).

Stress in studies or a breakdown in relationships do not cause the illness, these are merely precipitating factors.