Mental illness is often attributed to abnormal activity or an imbalance of the chemicals (neurotransmitters) in one's brain. Dopamine is an especially common chemical found in those with mental illness because it is responsible for transmitting signals between the nerve cells of the brain, reports Psychology Today. There is no direct method of measuring neurotransmitters, but with the technology available, there has been several links made between dopamine and schizophrenia.
Identification
Schizophrenia is a psychotic disorder that significantly impairs a person's functioning. To be considered schizophrenic, a person must have hallucinations and delusions lasting at least six months, according to Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR). Examples of hallucinations are hearing voices or seeing things that others do not. Delusions are erroneous beliefs that usually involve misinterpretation of perceptions or experiences, reports the DSM-IV-TR. Other common symptoms of schizophrenia are disorganized speech and thinking, immobility, social withdrawal and lack of emotion or energy, reports the DSM-IV-TR.
Dopamine Hypothesis
According to Bryn Mawr College, the exact cause of schizophrenia is unknown, but there is a hypothesis stating that individuals with schizophrenia produce too much dopamine, which causes their symptoms. This hypothesis originated from individuals who abuse amphetamine. Amphetamine increases dopamine, and users typically experience psychotic-like symptoms during their high. Additional evidence of the dopamine hypothesis comes from anti-psychotic medications. Psychiatrists give schizophrenics these medications to control their symptoms, which essentially block dopamine receptors in the brain, which decreases the amount of dopamine in the brain.
Considerations
There is much debate in the scientific community as to which mechanism in the brain--the prefrontal cortex, striatum or the limbic system--is the cause of the increased dopamine levels, reports Bryn Mawr College. As stated previously, there is no direct way to measure dopamine or any other neurotransmitter. Thus, researchers can only use the technology available, such as PET (positron emission tomography) scans.
Warning
Some researchers do not support the dopamine hypothesis. They believe that there are more neurotransmitters involved in schizophrenia than just dopamine, such as serotonin. In terms of the evidence from amphetamine users, these scientists contest that not all symptoms of schizophrenia are experienced during the amphetamine high. Additionally, it is said that anti-psychotic medications do not treat all the symptoms of schizophrenia, only delusions and hallucinations.
Expert Insight
Psychiatry, neurology and psychology are both expanding fields. Several hypotheses exist on the connection between neurotransmitters and mental illness, but nothing is certain as of yet. More research is needed to make conclusive and causal statements. If you are worried that you are experiencing any schizophrenia-like symptoms, consult with your physician or psychiatrist immediately.
References
- Psychology Today: What is Dopamine?
- American Psychiatric Association: The Diagnostic and Statistical Manual of Mental Disorders
- Bryn Mawr College: Dopamine Hypothesis of Schizophrenia
- "Understanding Schizophrenia. A guide to the new research in causes and treatment"; Keefe, R.S.E. and Harvey, P.D.; 1994
