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Brain Activity in Bipolar Disorder
These positron emission tomography scans of the brain of a person with bipolar disorder show the individual shifting from depression, top row, to mania, middle row, and back to depression, bottom row, over the course of 10 days. Blue and green indicate low levels of brain activity, while red, orange, and yellow indicate high levels of brain activity.
Dr. Michael Phelps/Lewis Baxton/UCLA School of Medicine
Mood disorders, also called affective disorders, create disturbances in a personís emotional life. Depression, mania, and bipolar disorder are examples of mood disorders. Symptoms of depression may include feelings of sadness, hopelessness, and worthlessness, as well as complaints of physical pain and changes in appetite, sleep patterns, and energy level. In mania, on the other hand, an individual experiences an abnormally elevated mood, often marked by exaggerated self-importance, irritability, agitation, and a decreased need for sleep. In bipolar disorder, also called manic-depressive illness, a personís mood alternates between extremes of mania and depression.
People with schizophrenia and other psychotic disorders lose contact with reality. Symptoms may include delusions and hallucinations, disorganized thinking and speech, bizarre behavior, a diminished range of emotional responsiveness, and social withdrawal. In addition, people who suffer from these illnesses experience an inability to function in one or more important areas of life, such as social relations, work, or school. See Psychosis.
Personality disorders are mental illnesses in which oneís personality results in personal distress or a significant impairment in social or work functioning. In general, people with personality disorders have poor perceptions of themselves or others. They may have low self-esteem or overwhelming narcissism, poor impulse control, troubled social relationships, and inappropriate emotional responses. Considerable controversy exists over where to draw the distinction between a normal personality and a personality disorder.
Cognitive disorders, such as delirium and dementia, involve a significant loss of mental functioning. Dementia, for example, is characterized by impaired memory and difficulties in such functions as speaking, abstract thinking, and the ability to identify familiar objects. The conditions in this category usually result from a medical condition, substance abuse, or adverse reactions to medication or poisonous substances. See Senile Dementia.
Dissociative disorders involve disturbances in a personís consciousness, memories, identity, and perception of the environment. Dissociative disorders include amnesia that has no physical cause; dissociative identity disorder, in which a person has two or more distinct personalities that alternate in their control of the personís behavior; depersonalization disorder, characterized by a chronic feeling of being detached from oneís body or mental processes; and dissociative fugue, an episode of sudden departure from home or work with an accompanying loss of memory. In some parts of the world people experience dissociative states as ďpossessionĒ by a god or ghost instead of separate personalities. In many societies, trance and possession states are normal parts of cultural and religious practices and are not considered dissociative disorders.
Somatoform disorders are characterized by the presence of physical symptoms that cannot be explained by a medical condition or another mental illness. Thus, physicians often judge that such symptoms result from psychological conflicts or distress. For example, in conversion disorder, also called hysteria, a person may experience blindness, deafness, or seizures, but a physician cannot find anything wrong with the person. People with another somatoform disorder, hypochondriasis (see Hypochondria), constantly fear that they will develop a serious disease and misinterpret minor physical symptoms as evidence of illness. The term somatoform comes from the Greek word soma, meaning ďbody.Ē
In contrast to people with somatoform disorders, people with factitious disorders intentionally produce or fake physical or psychological symptoms in order to receive medical attention and care. For example, an individual might falsely report shortness of breath to gain admittance to a hospital, report thoughts of suicide to solicit attention, or fabricate blood in the urine or the symptoms of rash so as to appear ill. Munchausen syndrome represents the most extreme and chronic variant of the factitious disorders.
Substance-related disorders result from the abuse of drugs, side effects of medications, or exposure to toxic substances. Many mental health professionals regard these disorders as behavioral or addictive disorders rather than as mental illnesses, although substance-related disorders commonly occur in people with mental illnesses. Common substance-related disorders include alcoholism and other forms of drug dependence. In addition, drug use can contribute to symptoms of other mental disorders, such as depression, anxiety, and psychosis. Drugs associated with substance-related disorders include alcohol, caffeine, nicotine, cocaine, heroin (see Opium), amphetamines, hallucinogens, and sedatives.
Eating disorders are conditions in which an individual experiences severe disturbances in eating behaviors. People with anorexia nervosa have an intense fear about gaining weight and refuse to eat adequately or maintain a normal body weight. People with bulimia nervosa (see Bulimia) repeatedly engage in episodes of binge eating, usually followed by self-induced vomiting or the use of laxatives, diuretics, or other medications to prevent weight gain. Eating disorders occur mostly among young women in Western societies and certain parts of Asia.
People with impulse-control disorders cannot control an impulse to engage in harmful behaviors, such as explosive anger, stealing (kleptomania), setting fires (pyromania), gambling (see Pathological Gambling), or pulling out their own hair (trichotillomania). Some mental illnessesósuch as mania, schizophrenia, and antisocial personality disorderómay include symptoms of impulsive behavior.
People have tried to understand the causes of mental illness for thousands of years. The modern era of psychiatry, which began in the late 19th and early 20th centuries, has witnessed a sharp debate between biological and psychological perspectives of mental illness. The biological perspective views mental illness in terms of bodily processes, whereas psychological perspectives emphasize the roles of a personís upbringing and environment.
These two perspectives are exemplified in the work of German psychiatrist Emil Kraepelin and Austrian psychoanalyst Sigmund Freud. Kraepelin, influenced by the work in the mid-1800s of German psychiatrist Wilhelm Griesinger, believed that psychiatric disorders were disease entities that could be classified like physical illnesses. That is, Kraepelin believed that the fundamental causes of mental illness lay in the physiology and biochemistry of the human brain. His classification system of mental disorders, first published in 1883, formed the basis for later diagnostic systems. Freud, on the other hand, argued that the source of mental illness lay in unconscious conflicts originating in early childhood experiences. Freud found evidence for this idea through the analysis of dreams, free association, and slips of speech.
This debate has continued into the late 20th century. Beginning in the 1960s, the biological perspective became dominant, supported by numerous breakthroughs in psychopharmacology, genetics, neurophysiology, and brain research. For example, scientists discovered many medications that helped to relieve symptoms of certain mental illnesses and demonstrated that people can inherit a vulnerability to some mental illnesses. Psychological perspectives also remain influential, including the psychodynamic perspective, the humanistic and existential perspectives, the behavioral perspective, the cognitive perspective, and the sociocultural perspective.
Many mental health professionals today favor a combination of perspectives, acknowledging that both biology and a personís environment play important roles in mental illness. This approach recognizes that people are not only products of the genes inherited from their parents, but products of the families and social worlds into which they are born. In this view, environments shape how biological factors will be manifested. For example, an infant may inherit genes that could enable her to become a tall adult, but if she is malnourished as a child, she will never achieve that potential. Likewise, an individual who does not possess a biological vulnerability for depression may nevertheless become severely depressed following the death of a loved one or after experiencing an act of torture.
Normal and Schizophrenic Brains
Magnetic resonance imaging (MRI) reveals structural differences between a normal adult brain, left, and the brain of a person with schizophrenia, right. The schizophrenic brain has enlarged ventricles (fluid-filled cavities), shown in light gray. However, not all people with schizophrenia show this abnormality.
Photo Researchers, Inc.;Science Source/Photo Researchers, Inc.
Psychiatry has increasingly emphasized a biological basis for the causes of mental illness. Studies suggest a genetic influence in some mental illnesses, such as schizophrenia and bipolar disorder, although the evidence is not conclusive.
Scientists have identified a number of neurotransmitters, or chemical substances that enable brain cells to communicate with each other, that appear important in regulating a personís emotions and behavior. These include dopamine, serotonin, norepinephrine (see epinephrine), gamma-amino butyric acid (GABA), and acetylcholine. Excesses and deficiencies in levels of these neurotransmitters have been associated with depression, anxiety, and schizophrenia, but scientists have yet to determine the exact mechanisms involved.
Genetics and Schizophrenia
Research shows that the more genetically related a person is to someone with schizophrenia, the greater the risk that person has of developing the illness. For example, children of one parent with schizophrenia have a 13 percent chance of developing the illness, whereas children of two parents with schizophrenia have a 46 percent chance of developing the disorder.
Booktionary Corporation. All Rights Reserved.
Advances in brain imaging techniques, such as magnetic resonance imaging (MRI) and positron emission tomography (PET), have enabled scientists to study the role of brain structure in mental illness. Some studies have revealed structural brain abnormalities in certain mental illnesses. For example, some people with schizophrenia have enlarged brain ventricles (cavities in the brain that contain cerebrospinal fluid). However, this may be a result of schizophrenia rather than a cause, and not all people with schizophrenia show this abnormality.
A variety of medical conditions can cause mental illness. Brain damage and strokes can cause loss of memory, impaired concentration and speech, and unusual changes in behavior. In addition, brain tumors, if left to grow, can cause psychosis and personality changes. Other possible biological factors in mental illness include an imbalance of hormones, deficiencies in diet, and infections from viruses.
In the late 19th century Viennese neurologist Sigmund Freud developed a theory of personality and a system of psychotherapy known as psychoanalysis. According to this theory, people are strongly influenced by unconscious forces, including innate sexual and aggressive drives. In this 1938 British Broadcasting Corporation interview, Freud recounts the early resistance to his ideas and later acceptance of his work. Freudís speech is slurred because he was suffering from cancer of the jaw. He died the following year.
Culver Pictures/Courtesy of the BBC Sound Archives. All rights reserved.
The psychodynamic perspective views mental illness as caused by unconscious and unresolved conflicts in the mind. As stated by Freud, these conflicts arise in early childhood and may cause mental illness by impeding the balanced development of the three systems that constitute the human psyche: the id, which comprises innate sexual and aggressive drives; the ego, the conscious portion of the mind that mediates between the unconscious and reality; and the superego, which controls the primitive impulses of the id and represents moral ideals. In this view, generalized anxiety disorder stems from a signal of unconscious danger whose source can only be identified through a thorough analysis of the personís personality and life experiences. Modern psychodynamic theorists tend to emphasize sexuality less than Freud did and focus more on problems in the individualís relationships with others.
Both the humanistic and existential perspectives view abnormal behavior as resulting from a personís failure to find meaning in life and fulfill his or her potential. The humanistic school of psychology, as represented in the work of American psychologist Carl Rogers, views mental health and personal growth as the natural conditions of human life. In Rogersís view, every person possesses a drive toward self-actualization, the fulfillment of oneís greatest potential. Mental illness develops when circumstances in a personís environment block this drive. The existential perspective sees emotional disturbances as the result of a personís failure to act authenticallyóthat is, to behave in accordance with oneís own goals and values, rather than the goals and values of others.
The pioneers of behaviorism, American psychologists John B. Watson and B. F. Skinner, maintained that psychology should confine itself to the study of observable behavior, rather than explore a personís unconscious feelings. The behavioral perspective explains mental illness, as well as all of human behavior, as a learned response to stimuli. In this view, rewards and punishments in a personís environment shape that personís behavior. For example, a person involved in a serious car accident may develop a phobia of cars or generalize the fear to all forms of transportation.
The cognitive perspective holds that mental illness results from problems in cognitionó-that is, problems in how a person reasons, perceives events, and solves problems. American psychiatrist Aaron Beck proposed that some mental illnessesósuch as depression, anxiety disorders, and personality disordersóresult from a way of thinking learned in childhood that is not consistent with reality. For example, people with depression tend to see themselves in a negative light, exaggerate the importance of minor flaws or failures, and misinterpret the behavior of others in negative ways. It remains unclear, however, whether these kinds of cognitive problems actually cause mental illness or merely represent symptoms of the illnesses themselves.