Books >> BrainScapes
Chapter V
Over the next decade new and innovative ways of understanding normal personality are likely to emerge. Up to now most theories on the subject have relied heavily on concepts drawn from the psychiatrist's consulting room. The "introvert," for instance, is regarded as only an attenuated version of the total self-absorption of the psychotic; the "extrovert" as a less exaggerated form of the manic. But the normal personality cannot be understood as simply a kind of watered-down version of the extremes of the neurotic or the psychotic. It exists on its own terms and is best understood without reference to mental illnesses. Temperament, for instance, is a dynamic trait built upon genetics, environment, and life experience. Identifying and describing these interrelated influences over the centuries have commanded the talents of both scientists and artists.
While Hippocrates' explanation of a personality based on humors had more art than science about it, a contemporary theory espoused by psychiatrist and geneticist Robert Cloninger intermixes the sciences of genetics, neuroscience, and mathematics. He posits four basic components of personality: reward dependence, harm avoidance, novelty seeking, and persistence. A person who seeks only the avoidance of pain and discomfort is likely to settle for less in life than the novelty seeker, who views such an orientation as an intolerable bore and emphasizes that life involves risks and unpredictable though always exciting changes in fortune.
Cloninger's four-dimensional grid makes it possible to predict not only how a person may feel about and react to a particular situation but even whether he or she is likely to react to a particular drug. For instance, Cloninger found that people who rate high in harm avoidance and reward dependence (traits that put them at the passive, socially dependent end of the social continuum) respond favorably to medications like Prozac.
Subsequent refinements are likely to link personality, character, and neurotransmitter profiles that more accurately reflect brain chemistry. These new and more comprehensive explanations are likely to include a person's reaction to chemical substances. For instance, a favorable response to drugs activating the dopamine system is one current way of identifying people suffering from forms of attention deficit disorder. While on the drug sufferers experience fewer difficulties in concentration and maintaining attention. Use of the drug can provide a kind of "therapeutic trial, " where the patient genuinely suffering from the disorder improves, while those mistakenly diagnosed develop only the side effects. Similar trials can be expected in the future that will resolve a most vexing issue: deciding when and under what circumstances people should be offered medications to solve life problems, and when they should be encouraged to take nothing and tough it out. I believe that additional understanding of brain chemistry will most likely reveal that our most intimate thoughts and feelings are the result of chemical processes, processes that can be modified by new drugs.
Traditionalists decry the use of drugs (I prefer the term medications, i.e., properly and legally prescribed substances, as opposed to illegal, unregulated "street" drugs) as a cop-out, an avoidance of the responsibility for self-determination. While I agree with the principle of self-determination, I have also witnessed the psychically debilitating effects of severe mental illness with its attendant despair and irresolution. As a result of his depression a depressed person is powerless to do anything to help himself. All the more valuable, therefore, will be a means of distinguishing seriously paralyzing depressions from mild and limited depressive episodes, perhaps no more than temporary "blue" periods. When observations and interviews fail to make such distinctions, a patient's response to medications can be a useful tool.
Our present concepts about personality, normal and otherwise, will eventually have to be revamped to include the chemical dimension, which until now has either been ignored or haphazardly manipulated by "recreational" drugs aimed at temporary modifications of mood and behavior. Self-description and description of others will include information relating to the neurotransmitter pathways that help define us. "Self-esteem," for instance, will be defined in terms of a genetic constitution toward high or low self-estimation. Such excursions into the psychophysiological are not new: we refer to some people as "adrenaline freaks, " an imprecise but intuitive appreciation of the importance of that neurotransmitter in their lives. But rather than implying a grim determinism, such knowledge will enhance human freedom since each person will have the opportunity to alter important aspects of himself.
Some respond with reservations, or even fright, to the opportunity to exert some measure of control over the workings of their own brain. "Drugs should not alter one's basic personality, it's essentially who we are, " is the most common expression of this view. But who is to decide what constitutes one's basic personality? Most people would have no problem with the dispensing of a drug capable of restoring the shattered personality of the Alzheimer's patient. Nor are there many objections to the use of antipsychotic drugs capable of doing away with hallucinations and delusions in a schizophrenic. It's the alteration of "normal" personalities that gives rise to controversy.
But is it "normal" for a person to become so frightened at the prospect of speaking before a sales conference that he'll do almost anything to get out of it, thus jeopardizing his advancement and career? Medications already exist that can help such a person, and even more sophisticated ones are promised in the future.
Rather than illnesses, various difficulties or problems in living will be targeted. Thus advances in our understanding of the brain, a scientific endeavor, will have an impact on humanistic issues; for the first time we will have the means to change those parts of our personality into an ideal of our own choosing. But since such choices will inevitably reflect society's current ideas about the "good life" and society's value judgments, our newfound medication-induced freedom may not be as liberating as we anticipate. Workaholics, anorexics, and various seekers of one kind of "perfection" or another will have available to them the chemical means of working longer and harder, eating less, and achieving more through single-minded dedication to increasingly narrow tasks. Already controversies are breaking out regarding some students' use of medications for the concentration difficulties attending their attention deficit disorders. When they take their medicine prior to a test they can concentrate better and score higher. But is that fair to the others, some parents are asking. Is such medication the equivalent of steroid use in athletes?
The questions raised by the new brain-altering chemicals will also influence our ideas of right and wrong and how our judicial system decides such matters. Is violence the result, as some are claiming, of a shortage of serotonin in the frontal lobes? And if indeed the frontal lobes of a murderer are found to contain less serotonin than normal, does that mean he is not responsible for the murders he has committed? This is not just a rhetorical question. Three weeks from the time I am writing these words I will be testifying as an expert witness in a court hearing to determine whether a man who has been tried and convicted of the murder of eight prostitutes should be executed or spend the rest of his life in prison.
Sitting before me on my desk is the report of another expert called by the defense, who is suggesting just such a correlation between a frontal lobe deficiency of serotonin and the accused's powerlessness to avoid stalking and killing his victims. His testimony rests on some research in animals that suggests that serotonin plays a role in behavioral inhibition, and that a decrease in this neurotransmitter leads to an inability to adopt passive or waiting attitudes toward frustrations, or to inhibit aggressive actions in the face of threatened punishment (the frequently mentioned failure to "learn from experience").
In humans there is also evidence of serotonin's role in aggression and violence. Lower levels of serotonin's breakdown product (the chemical5-H1AA or hydroxy indole acetic acid) appear in the spinal fluid of aggressive criminal offenders than in those with less aggressive incidents. Aggression against the self-suicide-also seems more common in people who have decreased levels of serotonin or 5-HIAA in their brain stem and cerebrospinal fluid. As a further indication of the role the lack of serotonin plays in violent behavior, consider that many of the medications useful for impulsive and aggressive disorders affect the serotonin system. And other disorders marked by problems with inhibiting certain impulses (kleptomania, pathological gambling, and self-injuring or self-mutilating behaviors) appear to be associated, at least on occasion, with lowered serotonin levels.
Based on correlations between lowered serotonin levels and some forms of violence, the opposing expert is testifying that the perpetrator, who is accused of carrying out a particularly gruesome and calculated series of murder mutilations (he dismembered several of his victims), suffers from a neurological disease. Yet several researchers reached the following conclusion about the serotonin violence correlation:
"The serotonin hypothesis of impulsivity is therefore perhaps best conceived of as an initial research model rather than a definitive model. Neurobiological research on impulse control disorders is in its infancy. . . . The relative lack of work on the neurobiology of the impulse control disorders makes any conclusions about their mechanisms tentative."
In short, a suggestive but unproven research model is being offered by the defense as a preferable theory of behavior rather than the concept of personal responsibility that is the underpinning of our judicial system. (The convicted serial killer originally pleaded insanity, a legitimate impairment of personal responsibility, but that plea was rejected by the jury, who found him guilty, and the judge, who condemned him to death.) This is a heavy, and I would suggest, ultimately inappropriate burden for the neurosciences to assume. If such an argument is accepted, our concept of good and evil will have to be replaced by notions having to do with neurotransmitter imbalance situation, in short, that will doom our traditional ideas about personal accountability to the rubbish heap.
While knowledge about the brain can provide help and direction in understanding social problems like serial killers and widespread violence, its validity as a moral arbiter is highly debatable. Serotonin, along with the other neurotransmitters, is a complex system involving multiple receptor subtypes and complex interactions with a so far undetermined number of other neurotransmitter systems. A degree of humility is called for, the humility of the man or woman who is comfortable enough to say: "We have learned much but there is still much that we do not know. Therefore we will be cautious and not make claims that our present knowledge about the brain cannot support."
Over the next two decades other challenging and intriguing developments can be expected in the neurosciences. Perhaps the most promising is nerve cell transplantation. By surgically implanting brain parts in affected patients, formerly untreatable or unresponsive behavioral illnesses will be brought under control.
Many people cringe at the notion of brain surgery as a means of curing neurological disorders, recalling the spate of "psychosurgical" operations carried out in the 1950s and 60s. Such operations, often performed in the interests of ideology rather than scientific research, resulted in thousands of tragically impaired people. But transplantation surgery is an utterly different matter.
The most common transplant operation, already in use today on a limited basis, is aimed at helping victims of Parkinson's disease.
Patients afflicted with this degenerative brain disease display a host of symptoms and signs resulting from a deficiency of the neurotransmitter dopamine. They move slowly and stiffly in a caricature of old age, even down to the characteristic tremor of their hands. Victims of Parkinson's seem out of touch with others since their faces, often compared to masks, display little emotion, and their voices, often barely audible, vary little in tone or timbre, no matter what the topic of conversation. In addition, the typical Parkinson's patient is bent over at the waist and walks with a shuffling, agonizingly slow gait.
With replacement of the deficient neurotransmitter dopamine, many of the signs of Parkinson's disease improve. In most cases this replacement consists of a daily dose of pills containing L-dopa, which upon entering the brain is transformed into dopamine. But for some Parkinson's patients, such medication doesn't work, and a neural transplant operation is their only hope.
Typical of such patients was Donald Wilson, who eventually became so incapacitated by his Parkinson's that he had to crawl on his hands and knees in order to navigate across his bedroom. Eventually the tremors and rigidity of his limbs grew so disabling that he spent the greater part of his waking hours in a wheelchair. In desperation Wilson offered to become the first American to have dopamine-producing brain tissue taken from an aborted fetus transplanted into his brain. After his operation Wilson was again able to walk and returned to his hobby of woodworking in his shop outside of Denver .
Wilson 's operation and others like it raise not only issues of technical difficulty, but ethical sensitivity as well. Many Americans equate abortion with murder, and even those who don't hold this view are still uncomfortable about using fetal tissues for transplantation.
A promising solution to this impasse may be forthcoming from recent developments in genetics. In the foreseeable future a person's skin cells may be able to be genetically modified so as to "turn on" the genes responsible for producing dopamine. This new approach is based on the fact that, as we have seen, with the exception of blood cells, every one of the body's trillions of cells carries the same genetic program..
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