Schizophrenia is a serious and chronic brain disorder that causes bizarre thoughts and behaviors in the sufferer. The National Institute of Mental Health estimates that schizophrenia affects as many as 1 percent of the American population in a given year. The disease appears in equal proportions in men and women, but average age of onset hovers around 25 years of age for men as compared to 30 years of age in women.
What is Schizophrenia?
Schizophrenia severely impairs the individual's ability to distinguish unreal and real events, resulting in distorted perceptions and an impaired level of functioning. HelpGuide.org explains that schizophrenia often involves delusions, in which the schizophrenic has firmly held irrational beliefs, and hallucinations, in which the individual hears or sees things that aren't there. Delusions may be persecutory in nature and result in the schizophrenic believing that others are trying to harm him. Auditory hallucinations may cause the sufferer to hear voices inside his head. Schizophrenics may exhibit blunted affect, or diminished emotions, loose associations and grossly inappropriate behavior. Without treatment, schizophrenics suffer severe disorganization in thought, speech and behavior and often become socially isolated, fearful and unable to care for themselves.
Chemical Causes
Biomedical researchers have concluded that schizophrenia may result from a complex combination of genetic, environmental and chemical factors. Schizophrenia.com notes that contributory causes include family history, prenatal malnutrition or viral infection, abnormalities in brain structure and chemical imbalance of key neurotransmiitters in the brain. Neurotransmitters are brain chemicals which facilitate the interplay between nerve cells. Recent studies implicate abnormalities in the amounts and mechanisms of the neurotransmitters dopamine, glutamate and serotonin in the brains of schizophrenics.
Dopamine
Evidence that dopamine is implicated in the development of schizophrenia is referred to as the dopamine hypothesis of schizophrenia, which posits that excessive amounts of dopamine are usually found in the brains of schizophrenics. The National Institute of Mental Health explains that this chemical irregularity may result from abnormalities in the genes responsible for maintaining dopamine levels, indicating once again that schizophrenia is likely to result from a mixture of genetic, structural and chemical factors. Proponents of the dopamine hypothesis point to the fact that anti-psychotic medications work by blocking dopamine receptors in the brain. Additionally, Psychiatric-Disorders.com gives us the information that illegal drugs such as cocaine and amphetamines increase dopamine levels and may also produce temporary psychotic symptoms in the user.
Glutamate
Glutamate is a neurotransmittier that also appears to be implicated in the development of schizophrenia. HelpGuide.org indicates that multiple studies reflect lower than normal levels of glutamate present in the brains of schizophrenics. This underactivity in glutamate metabolism actually gives credence to the dopamine hypothesis, due to the fact that dopamine receptors act to hinder the release of glutamate.
Serotonin
The Journal of the American Psychiatric Nurses Association notes that serotonin is now recognized as another neurotransmitter that plays a role in schizophrenia. Historically, pharmacologic treatment focused on drugs that reduce the activity of dopamine receptors. These drugs proved effective in treating what is known as positive symptoms of schizophrenia, such as hallucinations, delusions and disorganized behavior. However, the so-called negative symptoms of the disease, such as flat affect and catatonia, were not helped by the original antipsychotics. Newer antipsychotic drugs like olanzipine and risperidone act to block serotonin as well as dopamine receptors and seem promising in ameliorating both positive and negative symptoms of schizophrenia.
References
- HelpGuide: Understanding Schizophrenia
- Schizophrenia: Overview of Schizophrenia
- National Institute of Mental Health: What Causes Schizophrenia?
- Psychiatric-Disorders: Causes of Schizophrenia--Genetics, Environment and Dopamine
- Journal of the American Psychiatric Nurses Association: The Role of Serotonin and Dopamine in Schizophrenia
