Classifying Psychological Disorders

Classifying Psychological Disorders
For nearly 40 years, the American Psychiatric Association has published an official manual describing and classifying the various kinds of psychological disorders. This publication, the Diagnostic and Statistical Manual of Mental Disorders (DSM), has gone through four editions. The current version, known as the DSM-IV, provides careful descriptions ofsymptoms of different disorders, but includes little on causes and treatments.

Mood Disorders
Mood disorders are characterized by disturbances in mood or prolonged emotional state. The most common mood disorder is depression, a state in which a person feels overwhelmed with sadness, loses interest in activities, and displays other symptoms such as excessive guilt or feelings of worthlessness. TheDSM-IV distinguishes between two forms of depression. Major depressive disorder is an episode of intense sadness that may last for several months; in contrast, dysthymia involves less intense sadness but persists with little relief for a period of 2 years or more. Major depressive disorder is statistically linked with suicide. Some depressions become so intense that people become psychotic—that is,lose contact with reality.

Another, less common mood disorder is mania. People suffering from mania become euphoric ("high"), extremely active, excessively talkative, and easily distractible. Manic episodes rarely appear by themselves; rather, they usually alternate with depression. Such a mood disorder, in which both mania and depression are alternately present, sometimes interrupted byperiods of normal mood, is known as bipolar disorder.
Causes of Mood Disorders
Most psychologists believe that mood disorders result from a combination of biological, psychological, and social factors. Biological factors—including genetics and chemical imbalances within the brain—seem to play an important role in the development of depression and, especially, bipolar disorder. But just as biologyaffects psychological experience, so does psychological experience alter biological functioning. Cognitive distortions, illogical and maladaptive responses to early negative life events, can lead to feelings of incompetence that are reactivated whenever a new situation arises that resembles the original events. This psychological factor has been found to operate in many depressed people, though itis uncertain whether the cognitive distortions cause the depression or are caused by it. Finally, social factors—including genetics and chemical imbalances within the brain—seem to play an important role in the development of depression and, especially, bipolar disorder. But just as biology affects psychological experience, so does psychological experience alter biological functioning. Cognitivedistortions, illogical and maladaptive responses to early negative life events, can lead to feelings of incompetence that are reactivated whenever a new situation arises that resembles the original events. This psychological factor has been found to operate in many depressed people, though it is uncertain whether the cognitive distortions cause the depression or are caused by it. Finally, socialfactors such as troubled relationships have been linked with mood disorders.
Anxiety Disorders
In anxiety disorders, a person's anxiety is inappropriate to the circumstances. Anxiety disorders have been subdivided into many specific diagnostic categories. One familiar subtype is specific phobia, an intense, paralyzing fear of something that it is unreasonable to fear so excessively. Anothersubtype is social phobia—excessive, inappropriate fears connected with social situations or performances in front of other people. Agoraphobia is a less common and much more debilitating type of anxiety disorder that involves multiple, intense fears such as the fear of being alone or of being in public places or other situations that require separation from a source of security. Panic disorder is...