It is critical to seek a professional opinion if a prodromal period is suspected because early intervention (prior to or just following a first psychotic episode) can greatly minimize symptoms and alter the course of the disease, leading to much higher lifetime functioning. The period prior to acute onset is known as the prodromal period and often includes withdrawing from others and an increase in unusual thoughts and suspicions. It can be difficult to diagnose schizophrenia in teens because the first signs of the illness can include withdrawal from friends, a drop in grades, sleep problems, and irritability-common adolescent behaviors. Schizophrenia rarely occurs in children, but awareness of childhood-onset schizophrenia is increasing. In women with late-onset, hormonal changes associated with perimenopause or menopause are thought to be a contributing factor but the mechanism is unclear and has been a source of debate within the field of psychiatry.

Women are more likely to be diagnosed between ages 25 and 30, and again after age 45. The peak age for onset in men is between ages 21 and 25. Men present with more negative symptoms (see below) and become symptomatic at a younger age.

The symptom presentation and age of onset do differ between the sexes, however. Schizophrenia afflicts men and women in equal numbers and is found at similar rates in all ethnic groups around the world. These and other symptoms often render the individual fearful, withdrawn, or difficult to interact with. Individuals afflicted with this thought disorder experience hallucinations, disorganized thinking, and are prone to false and paranoid beliefs. Schizophrenia is a disabling mental illness that affects more than 1 percent of the world's population. Schizophrenia is a serious and chronic mental illness that impairs a person's thoughts and behavior, and if left untreated, can include psychosis.

Flat affect schizophrenia