Neurologists, psychiatrists, and biologists are still researching the origins of schizophrenia. There are several popular theories about the roots of this disease; however, many researchers agree that in any given person, schizophrenia may come from a combination of sources:
- Brain chemistry: Imbalances in certain neurotransmitters, or chemicals that allow communication between the brain, nerves, and vital organs, are involved in schizophrenia. In particular, dopamine and glutamate have been identified as neurochemicals that play a role in the thought patterns and behaviors of people with this disorder. According to the Proceedings of the National Academy of Sciences, one of the most popular theories about the origins of schizophrenia is the dopamine hypothesis, which associates schizophrenia with higher than normal levels of dopamine, a neurotransmitter that affects mood, cognition, sensory experience, metabolic activity, and other important functions.
- Brain structure: Imaging studies of human brains have been used to identify structural differences between the brains of individuals with schizophrenia and those without the disorder. These structural differences frequently occur in the frontal lobe.
- Heredity: The neurobiological features that contribute to the risk of developing schizophrenia may also have a genetic component. The National Alliance on Mental Illness states that several genes, rather than a single gene, are involved in this complex disorder, which is 10 percent more likely to occur among close relatives and 50 percent more likely in the case of twins.
- Environmental factors: A tendency toward schizophrenia may begin even before birth. Complications with pregnancy, maternal exposure to drugs or toxins, and fetal malnutrition may contribute to schizophrenia. Later in life, some researchers propose that viruses, industrial chemicals, chaotic home environments, or traumatic life experiences can set the stage for schizophrenia.
Substance abuse does not cause schizophrenia, but the chronic, excessive misuse of alcohol or drugs can increase the frequency and severity of psychotic episodes. In particular, drugs like cannabis, LSD, and other hallucinogenics have been linked with schizophrenic episodes. Stimulants like cocaine have also been implicated in the psychotic thought patterns and hallucinations of schizophrenia.