The exact causes of schizophrenia are unknown. Research suggests a combination of physical, genetic, psychological and environmental factors can make a person more likely to develop the condition. Some people may be prone to schizophrenia, and a stressful or emotional life event might trigger a psychotic episode.

Factors involved in the development of schizophrenia include:

• Brain development. Studies of people with schizophrenia have shown there are subtle differences in the structure of their brains.
• Imbalanced brain chemistry. Research suggests schizophrenia may be caused by an imbalance of neurotransmitters, which may involve excess dopamine or excess serotonin. Other theories implicate the roles of norepinephrine, GABA, neuropeptides, glutamate, and acetylcholine.
• Pregnancy and birth complications. Research has shown that people who develop schizophrenia are more likely to have experienced complications before and during their birth, such as a low birthrate, premature labor, or exposure to influenza or maternal starvation.
• Age of birth father. Some data indicate that the age of the father when a child is born has a correlation with the development of schizophrenia. In studies of schizophrenia patients with no family history of the illness on either their mother’s or father’s side, those born from fathers older than the age of 60 were vulnerable to developing the disorder.
• Drug abuse. While drugs do not directly cause schizophrenia, studies have shown that drug misuse increases the risk of developing schizophrenia. Certain drugs, particularly cannabis, cocaine LSD or amphetamines, may trigger symptoms of schizophrenia in people who are susceptible. Research has shown that teenagers and young adults who use cannabis regularly are more likely to develop schizophrenia in later adulthood.
• Stressful events. While stress does not cause schizophrenia, stressful events can trigger its development in someone already vulnerable to it. Leading psychological triggers are stressful life events such as death of a loved one, job loss, home loss, divorce, end of a relationship, or physical/sexual/emotional abuse.