activities that normally please the individual, and changes in sleep, libido, and appetite. Much more than mood is involved.

Depression is the leading cause of disability/sick days in the United States workforce and soon will be the second leading cause in the world. About half of the individuals who are challenged with depression have a recurrent form of the illness. While depression is more frequent in women, it is an equal opportunity disease, striking all socioeconomic classes, races, and age groups. It appears to be on the increase in frequency, but this may reflect greater public awareness of depression as an illness and not just as a condition of life that must be borne. Furthermore, family doctors and pediatricians are more alert to depression than they were in the past, so we cannot say if it is more frequent or simply better recognized. On the other hand, the stresses of contemporary life are such that it would not be a surprise if depression were actually on the increase.

Depression, unfortunately, is frequently associated with suicide. Suicide is on the increase in the United States, and this supports the hypothesis that depressive illnesses are on the increase. Presently, suicide is the eighth leading cause of death in the United States and is the second leading cause of death in the college-age population. The criterion of an official psychiatric diagnosis is a major depressive episode. The diagnosis requires that several symptoms must be present during the same two-week period and represent a change from a previous level of functioning. Depressed mood, most of the day and practically every day, is the leading subjective criterion. But the official diagnostic system recognizes that loss of interest or loss of pleasure in activities that are normally pleasurable to the individual is an extremely important criterion as well. Classical depressions are associated with weight loss and loss of appetite. We do, nevertheless, see certain depressions that are associated with increased appetite and weight gain. Insomnia, particularly waking up early in the morning, is the classical finding in depression, but again, there are cases where the person overeats and/or oversleeps. Fatigue or loss of energy is an extremely important finding. Impaired ability to think clearly, to concentrate, and to make decisions are very important diagnostic findings in this syndrome.

As stated before, there are certain periods in life when individuals are more vulnerable to depression. Following the birth of a child, it is not uncommon to see a mother experience severe depression within several weeks after delivery. These depressive conditions are frequently mixed and have features of suspiciousness or even frank paranoia. The

impact of depression is not only on the patient and the economy, but has a strong effect on the family of the patient. It can be extremely difficult to live with a person who is depressed and even more so when the condition is recurrent.

CORRECT DIAGNOSIS

An important issue in diagnosis is to make sure the individual is free of medical problems. For example, hypothyroidism can mimic many features of depression and is sometimes treated incorrectly as a depressive episode when, in fact, it represents a deficiency of thyroid hormone. It is essential, therefore, that any person who presents with a depressive episode be worked up medically to make sure that they do not have a medical condition that mimics depression. The important message is that depression can be treated successfully but must be diagnosed correctly. For example, depression associated with manic-depressive illness must be treated differently than recurrent depression, which is not associated with manic or hypomanic mood swings. The vast majority of patients can be treated successfully with a mixture of medication and psychotherapy.

VARIANTS OF DEPRESSION

An interesting variant of depression is called seasonal affective disorder (SAD). It is a depression that occurs when the days get shorter. The relative absence of sunlight is associated with a depressive illness. Such people respond to a change in location to a sunny climate or to exposure to lamps that simulate the spectrum of daylight. It is also interesting to note that the prevalence of depression increases as a function of distance from the equator. The further you are from the equator the more one sees depressive illnesses.

Another important category of depression is what used to be called masked depression. These are conditions in which the abnormal mood is not the major symptom, but rather the loss of energy, interest, ability to enjoy, etc. are the predominant features. These cases can be misdiagnosed because the absence of a depressed mood can confuse the clinician.

DEPRESSION'S EFFECT ON THE BODY

Depressive illnesses are frequently associated with other general medical conditions. Patients who have had a heart attack and who become depressed have a much worse prognosis than patients who do not become depressed. This appears to be true in a number of medical disorders. It is not clear why the depressive component adds to the morbidity