DSM-IV Criteria for Major Depression

Five or more of the following symptoms, one of which should be depressed mood or anhedonia must be present for at least two weeks:

• Depressed mood
• Loss of pleasure in usual activities (anhedonia)
• Feelings of worthlessness or inappropriate guilt
• Inability to concentrate
• Fatigue or loss of energy
• Insomnia or hypersomnia
• Psychomotor agitation or retardation
• Significant weight loss or gain
• Recurrent thoughts of death or suicide

Feelings of sadness need not be overtly present. In fact, anhedonia has been shown to be a more sensitive marker for depression than sadness in primary care populations. Therefore, clinicians should determine not only whether patients with suspected depression are participating in their regular activities but also whether they are continuing to enjoy those activities.

A complete review of systems and physical examination are important to screen for other medical conditions that may present as depression. Patients with atypical symptoms, older patients, and selected patients who fail to respond to initial treatment should be referred for a basic laboratory screen, including a complete blood count and measurement of electrolyte, calcium, and thyroid stimulating hormone levels. In women older than 50 years, new depressive symptoms should trigger thyroid testing even if other symptoms are absent.

Another key part of the evaluation is a review of medications . One approach is to discontinue the medication temporarily and follow the patient.