Schizophrenia: Overview and Risk Factors
Schizophrenia is a disease marked by abnormal thoughts and/or hallucinations, as well as disorganized speech and behavior. It affects about 1 percent of people worldwide.
Researchers believe that schizophrenia is in part caused by elevated levels of dopamine in the brain, but there are probably many other factors that are responsible for the disease.
- Age: The disease generally develops before age 25.
- Genetics: Genetic factors are thought to play a role, although no specific gene has been identified, and several genes may play a role. Approximately half of monozygotic (identical) twins are affected when the other twin has schizophrenia. The increased risk to dizygotic (fraternal) twins is around 15 percent, and first-degree relatives have about a 10 percent risk.
- Environmental exposures: Some investigators believe that certain early exposures are associated with a risk for schizophrenia. Fetal malnutrition, paternal age over 50 years, and births that occur during winter or spring are associated with increased risk. Children who were not breast-fed for at least two weeks have been shown to have increased risk of schizophrenia.
- Infection: Infection with the parasite Toxoplasma may affect the central nervous system and may be associated with schizophrenia.
Schizophrenia cannot be diagnosed through laboratory tests or imaging. A detailed psychiatric examination will help identify the disease and medical history and physical examination will help rule out other medical or psychiatric disorders.
- Medications are the most effective treatment, and discontinuing medication will typically lead to a recurrence of symptoms.
The older antipsychotic medications, such as haloperidol or chlorpromazine, can be very effective, but they carry a risk of undesirable side effects. Newer medications, such as risperidone and olanzapine, have fewer side effects.
- Treatment for schizophrenia should continue for life. This is often challenging, because affected individuals may not recognize their illness or seek treatment, and may stop treatment because of undesirable side effects or lack of access to mental health services.
- Emotional and physical support is an important component of treatment, and patients often have better results when direct family or community support is a part of their overall treatment plan.
- Cognitive-behavioral therapy and family therapy are useful to identify warning signs of relapse and improve treatment adherence. Family therapy has been shown to reduce relapse and rehospitalization.
- Group therapy, job training, and social skills training may improve quality of life and social functioning.
Schizophrenia: Nutritional Considerations
The following factors are associated with a reduced risk of schizophrenia or its complications:
- Avoidance of typical "Western" (i.e., high-fat, high-sugar) diets: Individuals with schizophrenia are at increased risk for heart disease. The greater risk results from several factors: patients' diets are often poor; smoking and physical inactivity are common; and antipsychotic medications may contribute to weight gain, high blood sugar, and high triglycerides (the chemical form of fat in the blood). As a result, patients can benefit from heart-healthy diets.
- Environmental factors: There is some evidence that exposure to the parasite Toxoplasma gondii may increase the risk for schizophrenia. Humans can become infected in a variety of ways, including ingestion of animal tissues and from contact with cat litter.
- Branched-chain amino acids: Although further study is needed, one group of investigators has consistently found that branched-chain amino acid formulas can reduce symptoms of tardive dyskinesia, a movement disorder that is a side effect of older antipsychotic medications.