Box 1. Diagnosis of Depression


Depressed or irritable mood
Decreased interest in pleasurable activities and ability to experience pleasure
Significant weight gain or loss (>5% change in a month)
Insomnia or hypersomnia
Psychomotor agitation or retardation
Fatigue or loss of energy
Feelings of worthlessness or excessive guilt
Diminished ability to think or concentrate
Recurrent thoughts of death or suicide

Depression (officially termed “Major Depression”) is diagnosed according to criteria in the Diagnostic Statistical Manual of Mental Disorders, which defines a “major depressive episode” as being characterized by at least five of the symptoms listed above. Each must be evident daily or nearly every day for at least two weeks. Severity is judged as mild, moderate or severe, based on the degree of impairment in daily occupational and social functioning. “Melancholic subtype” describes particularly severe cases, with prominent circadian variations in symptoms. Some patients with depression may exhibit symptoms of psychosis or loss of touch with reality (e.g., hallucinations or delusions). Anxiety symptoms are also seen in many individuals with depression, while others are blunted in terms of their emotional reactivity. Individuals with relatively mild but prolonged symptoms, which persist for at least two years, are considered to have “Dysthymia”. “Depressed Disorder Not Otherwise Specified” describes individuals with impaired function due to depressive symptoms but who do not meet the aforementioned criteria. “Adjustment Disorder with Depressed Mood” describes depressive symptoms that occur after a significant trauma (e.g., death of a loved one), although this can evolve into Major Depression. The range of symptoms that comprise depression, and the range of diagnostic categories, highlights the likely heterogeneity of the illness and the difficulty in establishing any given diagnosis with certainty.