National Alliance on Mental Illness
page printed from
(800) 950-NAMI;

Symptoms, Causes and Diagnosis


No single symptom positively identifies schizophrenia. An individual may have any combination of symptoms. Furthermore, an individual's symptoms can change over time.

The symptoms of schizophrenia are divided into three categories: positive, negative and cognitive symptoms.

Positive Symptoms are also known as "psychotic symptoms" because the person has lost contact with reality in certain ways. (read more)


While an exact cause of schizophrenia is still unknown, researchers do know that the brains of people living with schizophrenia are different from those undiagnosed with the illness.

It is too early to classify schizophrenia as either a neurodevelopmental (impairment of the growth and development of the brain) or a neurodegenerative (progressive loss of structure or function of neurons) disorder, as both seem to occur over the course of the illness.

Research strongly suggests the emergence of schizophrenia is a result of both genetic and environmental factors. (read more)


Diagnosing schizophrenia is not easy. The first signs of its manifestation may only be a change of friends, a drop in grades or irritability and not even appear to be "typical" signs of psychosis.

Complicating diagnosis further is that the symptoms of schizophrenia also resemble those of other mental and physical health problems, such as bipolar disorder and brain tumors.

Schizophrenia symptoms can also be mimicked in the effects of illicit drugs, including the use of methamphetamines. As a consequence there is no one single physical or lab test that is able on its own to accurately diagnosis schizophrenia. (read more)

ask the doctor read our report take our quiz download brochure