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Brain Neurotransmitters and Illness

Neurotransmitters and Synapse

Encephalitis, OCD symptoms, and Parkinsonism:

Between 1915 and about 1924, a severe epidemic of viral encephalitis plagued areas in Europe and North American. Constantin von Economo, both a clinician and a pathologist, studied the outbreak. The infection caused lesions in the substantia nigra. Von Economo described three types of this illness. 1) The symptoms of the somnolent-opthalmoplegic form were somnolence, often leading to coma and death, paralysis of cranial nerves, extremities and eye muscles and expressionless faces. 2) The hyperkinetic form manifested itself with restlessness, motor disturbances as twitching of muscle groups, involuntary movements, anxious mental state and insomnia or inversion of sleep patterns. 3) The amyostatic-akinetic form often lead to a chronic state similar to Parkinson's disease, called postencephalitic Parkinsonism. The symptoms were weakness of muscles, rigidity of movements and insomnia or sleep inversion

Flu Epidemic - 1918

To illustrate how infection that damages delicate brain neurocircuitry affects behavior, in The Boy Who Couldn't Stop Washing: The Experience & Treatment of Obsessive-Compulsive Disorder (1989), Judith L. Rapoport cites von Economo's experiences. He observed that his patients did not say "I have a twitch in my hand," as an epileptic patient might say, but rather as a rule said, "I have got to move my hand that way." In other words, patients often perceived that the movement was an act of will and intention. Rapoport writes: "The frequent subjectivization of these processes, experienced as compulsory by the patients, is one of their characteristic attributes." Rapoport points out that von Economo "went on to worry about how a 'lower' part of the brain, the basal ganglia, could be responsible for such a complex function as that of 'will' and 'intentionality.'"

In Brainscapes: An Introduction to What Neuroscience Has Learned about the Structure, Function, and Abilities of the Brain (1995), Richard M. Restak quotes a psychiatrist's observations of his postencephalitic patient: "He worried over disturbing ideas, whether his employer or his employer's wife was insulted by certain things he might have said, whether he really had closed the window, whether the door of the room was properly closed. He would wash his hands repeatedly during these episodes, look under the bed to see if anyone were hiding there, and dust his chair carefully before seating himself."

The experiences recounted above indicate that infections that damage dopamine neurocircuitry in the brain can somehow produce both Parkinson's-like and obsessive-compulsive symptoms. Later in this narrative, this infection will be discussed as a possible etiologic agent in OCD. For now, it is clear that the primary player in the SEEKING system, dopamine, is involved in both the physical aspects of movement and the mental aspects of motivation.

Tardive Dyskinesia:

As in Parkinson's disease, the nigrostriatal dopamine pathway is also implicated in tardive dyskinesia, but in a different way. Tardive dyskinesia results as a side effect of larger doses of antipsychotic drugs used to treat schizophrenia and psychotic episodes in other illnesses. The aim of using these medicines is to block dopamine receptors, specifically D2 receptors, in the dopamine pathway associated with illness. Some medicines, however, including older so-called typical antipsychotics as well as some of the newer atypical antipsychotics, block D2 receptors in multiple pathways including the nigrostriatal pathway, which may result in movement problems, especially when medication dosages are high and long-term. The National Institute of Neurological Disorders and Stroke provides the following information: "Tardive dyskinesia is characterized by repetitive, involuntary, purposeless movements. Features of the disorder may include grimacing, tongue protrusion, lip smacking, puckering and pursing, and rapid eye blinking. Rapid movements of the arms, legs, and trunk may also occur. Involuntary movements of the fingers may appear as though the patient is playing an invisible guitar or piano."

In the video embedded here, eighteen-year-old Lydia, has recorded her tardive dyskinesia symptoms. She developed symptoms after taking Seroquel for bi-polar disorder. Lydia illustrates how she can focus on symptoms in order to stop them. When she returns to a task, however, shifting her attention away from symptoms, they often return.

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We discuss antipsychotic medications in more detail, especially in relation to attenuating dopamine transmission as a means of preventing obsessions and compulsions, in Part 3 of, in OCD Treatments Including Antipsychotic Medications.

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