Definition
Is Schizophrenia a Mental Illness or a Physical Illness?
Modern society makes a clear distinction between diseases that are referred to as "medical illnesses" and those that we call "mental illnesses". Does this make sense?
If we examine what we know about schizophrenia and Parkinson's Disease, this separation seems to be arbitrary, at best. As we accumulate additional knowledge regarding other mental illnesses, one might presume that this distinction will eventually disappear.
When we examine schizophrenia and Parkinson’s disease there seems to be no logical reason to distinguish one from the other. They are similar illnesses that both involve abnormal amounts of the neurotransmitter dopamine. There is inadequate dopamine activity in Parkinson’s disease and excessive dopamine activity in schizophrenia. Based upon this observation alone, it would seem that they are both clearly medical illnesses, but our society chooses to distinguish one from the other.
A neurotransmitter is a chemical substance that transmits nerve impulses across a tiny space called the synapse, or synaptic cleft, to another nerve, a muscle or to a gland. All nerve transmissions in our body and brain are accomplished by these chemicals. They include dopamine, epinephrine, norepinephrine, acetylcholine and others.
Outside the brain, dopamine increases our heart rate and blood pressure, but that dopamine is unable to cross the blood-brain barrier; the thin membrane between the walls of tiny blood vessels in the brain and brain tissue.
Inside the brain, dopamine is responsible for many things. It regulates prolactin, a hormone that causes us to produce breast milk and controls menstrual cycles. It affects how our brain controls movement. It also affects the flow of information in our frontal lobes. Reduced amounts of dopamine here results in problems with memory, attention and problem solving, and contributes to what are referred to as the “negative signs and symptoms” of schizophrenia.
Two much dopamine in the brain is related to psychosis. Dopamine is also involved in the activity of the brain’s pleasure centers. It is the “feel good” neurotransmitter and helps with motivation. Cocaine and amphetamines dramatically increase levels of dopamine and so we euphoric, but only for a short time, until we deplete our stores of dopamine. Then we are likely to feel extremely dysphoric.
In the case of Parkinson’s Disease, there is not enough dopamine in certain areas of the brain. Because of this, a person with this illness has difficulties with movement. They become slow and may experience problems initiating movement when they try to rise from a chair or begin to walk. Their arms don’t swing freely by their sides when they walk and they loose the ability to easily move their facial muscles. As a result, they have little facial expression. The also encounter problems with smooth controlled movements and so develop tremors.
People with Parkinson's Disease also experience cognitive problems due to the dopamine depletion caused by their disease. Individuals who suffer from schizophrenia may encounter the same problems, but as a consequence of the artificial depletion caused by antipsychotic medications.
In the case of schizophrenia, there is excessive dopamine activity in some regions of the brain which causes psychosis and other symptoms. Antipsychotic drugs, the medications used to treat schizophrenia, block dopamine. This helps to reduce the "positive symptoms" of schizophrenia: delusions, hallucinations, and disorganized thinking or behavior.
At the same time, this dopamine blockade may worsen the negative symptoms of schizophrenia: anhedonia (the inability to experience pleasure), apathy, and social withdrawal. It may also produce what is called “pseudo-parkinsonism”. Patients have symptoms just like Parkinson’s Disease except that they resolve completely when the antipsychotic medication is withdrawn or the dosage is reduced.
Sometimes patients can’t afford to stop or reduce the dose of their medication and so anti-parkinson’s medications are used to make those side effects go away.
In the case of Parkinson’s disease, medications are used to increase levels of dopamine in the brain. While this improves the symptoms of Parkinson’s disease, too much dopamine may cause symptoms of psychosis, like those seen with schizophrenia. Those symptoms may require antipsychotic medications, which theoretically could make Parkinson’s symptoms worse. Fortunately, there are some antipsychotic medications that can control the symptoms of psychosis without exacerbating the symptoms of Parkinson’s Disease.
Certainly a comprehensive understanding of either schizophrenia or Parkinson’s Disease reveals more than simply altered levels of dopamine. There seem to be complex and widespread alterations in the structure of the CNS (Central Nervous System) as well, at least in schizophrenia.
Even a basic understanding of schizophrenia and Parkinson’s Disease makes it obvious that both illnesses are clearly medical illnesses. Hopefully the discrimination that patients with schizophrenia experience at the hands of insurance companies and government agencies will cease to exist as more people come to better understand this disease.
(Sources: The author's knowledge base, unless otherwise noted.)
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