Depression Diagnosis: Symptoms, Criteria, and Evaluation Process

DSM-5 Criteria for Major Depressive Episode

≥5 of the following during the same 2-week period (at least one: 1 or 2):

1. Depressed mood most of day, nearly daily.
2. Markedly diminished interest/pleasure (anhedonia).
3. Significant weight loss/gain or appetite change.
4. Insomnia or hypersomnia.
5. Psychomotor agitation or retardation.
6. Fatigue/loss of energy.
7. Feelings of worthlessness/excessive guilt.
8. Diminished concentration/indecisiveness.
9. Recurrent thoughts of death, suicidal ideation/attempt.

Symptoms cause clinically significant distress/impairment; not attributable to substance/medical condition; not better explained by other disorders.

Diagnostic Process

1. Clinical interview: Symptom review, history, functional impact, safety assessment.
2. Screening tools: PHQ-9 (validated, 9 items), BDI-II, HAM-D.
3. Medical workup: Rule out mimics (thyroid, B12/folate, iron, electrolytes, cortisol, medications, substance use).
4. Differential: Bipolar, persistent depressive disorder, adjustment disorder, grief, medical/neurologic conditions.

Who Diagnoses

• Psychiatrist (MD), psychologist (PhD/PsyD), primary care physician, LCSW, LMHC, psychiatric NP/PA.

Treatment Follows Diagnosis

• Psychotherapy (CBT, IPT, behavioral activation).
• Antidepressants (SSRI/SNRI first-line).
• Combined > either alone for moderate-severe.
• Neuromodulation (TMS, ECT) for treatment-resistant.

Urgent Note

Suicidal ideation with plan/intent = emergency. Call 988 (US) or local crisis line.