In a major medical study, depression caused significant problems in the functioning of those affected more often than did arthritis, hypertension, chronic lung disease, and diabetes, and in two categories of problems, as often as coronary artery disease. Depression can increase the risks for developing coronary artery disease, HIV, asthma, and some other medical illnesses. Furthermore, it can increase the morbidity (illness) and mortality (death) from these conditions. Depression is usually first identified in a primary care setting, not in a mental health practitioner's office. Moreover, it
often assumes various disguises, which causes depression to be frequently under-diagnosed. In spite of clear research evidence and clinical guidelines regarding therapy, depression is often under-treated. Hopefully, this situation can change for the better. For full recovery from a mood disorder, regardless of whether there is a precipitating factor or it seems to come out of the blue, treatments with medications and psychotherapy are necessary.

Depressive disorders come in different forms, just as do other illnesses, such as heart disease and diabetes. There are variations in the number, severity, and persistence of symptoms.

Major Depression

Major depression is characterized by a combination of symptoms, including sad mood (see symptom list), that interfere with the ability to work, sleep, eat, and enjoy once-pleasurable activities.
Disabling episodes of depression can occur once, twice, or several times in a lifetime