But there is abundant evidence that families may be able to help improve the outcome of the illness. No laboratory tests exist to determine a diagnosis of schizophrenia. Like other mental and emotional disorders, a diagnosis of schizophrenia is made solely on the basis of the person's behavior, thoughts and feelings. Through careful observation and interviewing, competently trained psychiatrists, psychologists, nurses, social workers, and therapists can detect major disturbances in a person's functioning, including the presence of psychotic symptoms. However, before a diagnosis of schizophrenia is made, medical factors such as a brain tumor or the effects of substance abuse are ruled out.
Schizophrenia is considered to be a disorder caused by a combination of factors.
Structural abnormalities of the brain, and biochemical deficiencies or an imbalance of special brain chemicals called neurotransmitters are two factors linked to the disorder. Studies have also shown that if a close relative suffers from schizophrenia then there is a 1 in 10 chance that another immediate family member may also experience the disorder. This vulnerability may also play a role in determining the course of the illness in an individual. Environmental stress also appears to be an important factor in the development of schizophrenia. Personal and family events such as an adolescent's leaving home, a young adult's entrance into a new career or peer group, a death in the family, or the breakup of a significant relationship are some of the stressors that may precede the onset of schizophrenia.