Mood and Anxiety Disorders
Core concepts
Major depressive disorder: ≥5 of 9 symptoms for ≥2 weeks, including depressed mood or anhedonia, with functional impairment. Understand specifiers (melancholic, atypical, psychotic, peripartum, seasonal). Bipolar I (manic episode ≥1 week or hospitalization) vs bipolar II (hypomania ≥4 days + depression, no mania). Know the treatment hierarchy: SSRIs first-line for depression; bipolar requires mood stabilizer before antidepressant to avoid switch. Anxiety disorders: GAD (≥6 months excessive worry), panic disorder (recurrent unexpected attacks + anticipatory anxiety), social anxiety, specific phobia, OCD (obsessions/compulsions, insight specifier), PTSD (trauma + intrusion, avoidance, negative cognitions, hyperarousal ≥1 month). Understand first-line psychotherapy (CBT, exposure) and pharmacotherapy (SSRIs/SNRIs). Screening: PHQ-9, GAD-7.
Traps
Antidepressant monotherapy in bipolar is a classic error - screen for mania before prescribing. Distinguish grief from major depression (though DSM-5-TR removed the bereavement exclusion). Panic attacks can occur in any anxiety disorder - panic disorder requires unexpected attacks plus ≥1 month of worry/behaviour change. OCD is not simply 'anxiety'; it has its own category.
Rule of thumb
Always screen for bipolar disorder before starting an antidepressant: ask about past hypomanic/manic episodes.