Introduction The study of biomedical bases for mental illnesses and their treatment is called biological psychiatry or biopsychiatry. A basic premise of biopsychiatry is that psychiatric symptoms occur in many conditions—some psychological and some medical.
Inherent in this viewpoint is a different outlook on mental illness. Faced with a patient who is lethargic, has lost his or her appetite, cannot sleep normally, and feels sad, traditional psychotherapists may diagnose the patient as having one of the depressive disorders. Usually, the diagnostic bias is that this illness is psychological in origin and calls for treatment with psychotherapy. Biopsychiatrists, however, see depression not as a diagnosis but as a symptom of the patient’s condition. The task of diagnosing, of finding the underlying illness, remains to be done.
After examining the patient and performing a battery of medical tests, the biopsychiatrist may also conclude that the condition is a primary mood disorder. Further tests may reveal whether it is caused by life stresses, in which case psychotherapy is appropriate, or by biochemical imbalances in the brain, in which case drug therapy—perhaps in concert with psychotherapy—is appropriate. The medical tests may indicate that the depression is secondary to a medical condition, such as Addison's disease or cancer of the pancreas, in which case medical treatment of the primary condition is needed.
Physiological Bases of Psychiatric Conditions An important distinction must be made between psychiatric conditions resulting from the psychological stress of having a serious illness and psychiatric conditions resulting from chemical imbalances or endocrine disturbances produced by an illness. For example, the knowledge that a person has pancreatic cancer can certainly lead to depression. This is a primary mood disorder that can be treated with psychotherapy. According to biopsychiatrist Mark Gold, however, depression occurs secondarily to pancreatic cancer in up to three-quarters of patients who have the disease and may precede physical symptoms by many years. In such a case, psychotherapy not only would be pointless but also would actually put the patient’s life at risk if it delayed diagnosis of the underlying cancer.
According to Gold, there are at least seventy-five medical diseases that can produce psychiatric symptoms. Among these are endocrine disorders, including diseases of the thyroid, adrenal, and parathyroid glands; disorders of the blood and cardiovascular system; infectious diseases, such as hepatitis and syphilis; vitamin deficiency diseases caused by insufficient niacin or folic acid; temporal-lobe and psychomotor epilepsies; drug abuse and side effects of prescription drugs; head injury; brain tumors and other cancers; neurodegenerative diseases such as Alzheimer’s, Huntington’s, and Parkinson’s diseases; multiple sclerosis; stroke; poisoning by toxic chemicals, such as metals or insecticides; respiratory disorders; and mineral imbalances.
After medical illnesses are ruled out, the psychiatric symptoms can be attributed to a primary psychological disorder. This is not to say that biomedical factors are unimportant. Compelling evidence indicates that the more severe psychotic disorders are caused by biochemical imbalances in the brain.
Genetic Predispositions and Biochemical Imbalances The evidence of genetic predispositions for schizophrenia, major depressive disorder, and bipolar disorder is strong. The function of genes is to regulate biochemical activity within cells, which implies that these disorders are caused by biochemical abnormalities.
Research suggests that schizophrenia, in most cases, results from an abnormality in the dopamine
neurotransmitter system in the brain. All drugs that effectively treat schizophrenia block the action of dopamine, and the more powerfully they do so, the more therapeutically effective they are. Furthermore, overdoses of drugs, such as amphetamines, that strongly stimulate the dopamine system often cause a schizophrenia-like psychosis. Finally, studies show that, in certain areas of the brain in schizophrenic patients, tissues are abnormally sensitive to dopamine.
In major depressive disorders, the biogenic amine theory is strongly supported. Biogenic amines, among which are dopamine, norepinephrine, and serotonin, are neurotransmitters in the brain that are concentrated in the limbic system, which regulates emotional responses. Biogenic amines were originally implicated by the observation that drugs that deplete them in the brain, such as reserpine, frequently cause depression, whereas drugs that stimulate them, such as amphetamines, cause euphoria. Studies of cerebrospinal fluid have revealed abnormalities in the biochemical activity of these amines in some depressed patients. In many suicidally depressed patients, for example, serotonin activity in the brain is unusually low. In other depressed patients, norepinephrine or dopamine activity is deficient. These patients often respond well to antidepressant medications, which increase the activity of the biogenic amine neurotransmitter systems.
Less severe neurotic emotional disturbances may also have biochemical explanations in some patients. Research suggests that mild or moderate depressions often result from learned helplessness, a condition in which people have learned that their behavior is ineffective in controlling reinforcing or punishing consequences. Experiments show that this produces depletion of norepinephrine in the brain, as do other psychological stressors that cause depression. These patients also are sometimes helped by antidepressant drugs.
Finally, many anxiety disorders may result from biochemical imbalances in the brain. Drugs that alleviate anxiety, such as chlordiazepoxide (Librium) and diazepam (Valium), have powerful effects on a brain neurotransmitter called gamma-aminobutyric acid (GABA), as do other tranquilizers, such as alcohol and barbiturates. GABA is an inhibitory neurotransmitter that acts to keep brain activity from running away with itself, so to speak. When GABA is prevented from acting, the result is agitation, seizures, and death. Positron emission tomography (PET) scans of the brains of people suffering from panic attacks show that they have abnormally high activity in a part of the limbic system called the parahippocampal gyrus, an effect that might be caused by a GABA deficiency there.
Improving Diagnosis and Care Understanding the biomedical factors that cause illnesses with psychiatric symptoms leads directly to improved diagnoses and subsequent patient care. Numerous studies have shown that psychiatric disorders are misdiagnosed between 25 and 50 percent of the time, the most persistent bias being toward diagnosing medical problems as psychological illnesses. A study published in 1981 by Richard Hall and colleagues found that, of one hundred psychiatric patients admitted consecutively to a state hospital, eighty had a physical illness that required medical treatment but had not been diagnosed in preadmission screening. In twenty-eight of these patients, proper medical treatment resulted in rapid and dramatic clearing of their psychiatric symptoms. In another eighteen patients, medical treatment resulted in substantial improvement of their psychiatric conditions. In an earlier study, Hall and colleagues found that 10 percent of psychiatric outpatients—those whose conditions were not severe enough to require hospitalization—had medical disorders that caused or contributed to their psychiatric illnesses.
Psychiatric symptoms are often among the earliest warning signs of dangerous, even life-threatening, medical illnesses. Therefore, proper physical evaluation and differential diagnosis, especially of patients with psychiatric symptoms not obviously of psychological origin, is critical. In other cases, psychiatric illnesses result from biochemical imbalances in the brain. In any case, patients and therapists alike must be wary of uncritically accepting after-the-fact psychological explanations. A psychological bias can all too easily become a self-fulfilling prophecy, to the detriment of the patient’s health and well-being.
Hall and colleagues found that a medical workup consisting of psychiatric and physical examinations, complete blood-chemistry analysis, urinalysis and urine drug screening, an electrocardiogram (EKG), and an electroencephalogram (EEG) successfully identified more than 90 percent of the medical illnesses present in their sample of one hundred psychiatric patients. The authors recommend that such a workup be done routinely for all patients admitted to psychiatric hospitals.
E. Fuller Torrey makes similar recommendations for patients admitted to psychiatric hospitals because of schizophrenia. He recommends that a thorough examination include a careful and complete medical history and mental-status examination, with assistance from family members and friends if necessary. Physical and neurological examinations are also recommended. A blood count, blood-chemical screen, and urinalysis should be done to reveal conditions such as anemia, metal poisoning, endocrine or metabolic imbalances, syphilis, and drug abuse. A computed tomography (CT) scan may be necessary to clarify suspicions of brain abnormalities. Some doctors recommend that a CT scan be done routinely to detect conditions such as brain tumors, neurodegenerative diseases, subdural hematomas (bleeding into the brain resulting from head injuries), viral encephalitis, and other conditions that might be missed on initial neurological screening. Torrey also recommends a routine examination of cerebrospinal fluid obtained by lumbar puncture, which can reveal viral infections, brain injury, and biochemical abnormalities in the brain, and a routine electroencephalogram, which can reveal abnormal electrical activity in the brain caused by infections, inflammations, head injury, or epilepsy.
If any medical disorder is discovered, it should be treated appropriately. If this does not result in clearing the psychiatric symptoms, Torrey recommends that antipsychotic medications be given. If the initial drug trial is unsuccessful, then the dosage may have to be adjusted or another drug tried, because a patient’s response to medication can be quite idiosyncratic. About 5 percent of patients react adversely to medication, in which case, it may have to be discontinued.
Biopsychiatrist Gold makes parallel recommendations for patients with depressive and anxiety disorders. In patients who have depressive symptoms, tests for thyroid function are particularly important. Perhaps 10 to 15 percent of depressed patients test positive for thyroid disorder. Hypothyroidism, especially before the disease is fully developed, may present only psychiatric, particularly depressive, symptoms. Thyroid disorders may be indicated by depression, mania, or psychosis. Blood and urine screens for drug abuse are also indicated for patients with depression.
Patients who are found to have a primary mood disorder may be candidates for antidepressant drug therapy. Because responses to these medications are highly idiosyncratic, careful monitoring of patients is required. Blood tests can determine whether the drug has reached an ideally effective concentration in the body.
In some cases, even biological depressions can be treated without drugs.
Seasonal affective disorder (SAD), also called winter depression, may be treated with exposure to full-spectrum lights that mimic sunlight. Studies suggest that this alters activity in the pineal gland, which secretes melatonin, a hormone that has mood-altering effects. Similarly, some depressions may result from biological rhythms that are out of synchronization. Exposure to light is often helpful in such cases.
In anxious patients, tests for endocrine function, especially hyperthyroidism, are called for, as are tests of the cardiovascular system and tests for drug abuse. In patients in whom no primary medical disorder is identified, the use of antianxiety medications may be indicated. Patients on medication should be closely monitored. Psychotherapy, such as behavior therapy for avoidant behaviors engendered by panic attacks and phobias, is also indicated.
As the public becomes more knowledgeable about the biomedical factors in psychiatric illnesses, malpractice lawsuits against therapists who misdiagnose these illnesses or who misapply psychotherapy and psychoactive drug therapy have become more common. This suggests that mental health providers may have to become more medically sophisticated and rely more on medical testing for the purpose of the differential diagnosis of illnesses presenting psychiatric symptoms.
History of Psychiatric Care Theories of abnormal behavior have existed since prehistoric times. At first, these centered on supernatural forces. Behavior disturbances were thought to result from invasion by evil spirits. Treatment was likely to consist of trephination—the practice of drilling a hole in the skull to allow malevolent spirits to escape.
In the fourth century BCE, the Greek physician Hippocrates proposed the first rudimentary biomedical theory. He proposed that illnesses, including mental illnesses, resulted from imbalances in vital bodily fluids. His break with supernatural explanations resulted in more humane treatment of the mentally ill. However, by medieval times, theories of abnormality had reverted to demonology. Mental illness was often attributed to demoniac possession, and “treatment” was sometimes little less than torture.
The Renaissance, with its revival of learning and interest in nature, initially saw little change in this attitude. People whose behavior was considered peculiar were often accused of witchcraft or of conspiring with the devil. As knowledge of the human organism increased, however, superstitions again gave way to speculation that “ insanity” resulted from physical illness or injury. The mentally ill were consigned to asylums where, it was hoped, they would be treated by physicians. In most cases, however, asylums were essentially prisons, and medical treatment, when available, was rarely effective.
Two historical movements were responsible for restoring humane treatment to the mentally ill. The first was a moral reform movement ushered in by such individuals as Philippe Pinel in France, William Tuke in England, and Dorothea Dix in the United States.
The second was continuing research in chemistry, biology, and medicine. By the nineteenth century, the brain had become recognized as the seat of human reasoning and emotion. Once thought to be a place of supernatural happenings, the brain was finally revealed to be an organ not unlike the liver. Like the liver, the brain is subject to organic disturbances, and the result of these is similarly predictable—namely, psychological abnormalities. Discovery of diseases, such as advanced syphilis, that cause brain deterioration and are characterized by psychological symptoms supported this organic model.
By the mid-twentieth century, little reasonable doubt remained that some psychological disturbances have biomedical causes. Interest centered especially on schizophrenia, major depressive disorder, and bipolar disorder. Genetic studies strongly indicated that organic factors existed in each of these illnesses, and research was directed toward finding the biomedical fault and effecting a cure.
Paradoxically, effective treatments were found before medical understanding of the disorders was achieved. Therapeutic drugs were developed first for schizophrenia, then for depression, and finally for anxiety. These drugs proved to be important research tools, leading directly to discovery of neurotransmitter systems in the brain and helping elucidate the biochemical nature of brain functioning. Much neuroscience research is still motivated by the desire for a better biomedical understanding of psychological disorders, which will ultimately lead to more effective treatments and patient care for these conditions.
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