Mood Disorders (Depressive and Bipolar Disorders)
What the exam tests
Mood-disorder questions test criteria, polarity, course, suicide risk and treatment selection. The key skill is distinguishing unipolar depression, bipolar I, bipolar II and substance- or medically induced mood syndromes.
Core rules
- Major depression: five of nine symptoms for two weeks, including depressed mood or anhedonia, with impairment.
- Bipolar I: at least one manic episode, with or without depression. Bipolar II: hypomania plus major depression, never mania.
- Mixed features mean subsyndromal opposite-pole symptoms during an episode; they raise suicide and switching risk.
- First-line unipolar depression: psychotherapy, SSRI or other antidepressant; severe or psychotic depression may need ECT.
- Bipolar disorder: mood stabiliser such as lithium or valproate; antidepressant monotherapy risks switching. Monitor lithium levels, renal and thyroid function.
Worked example
A 22-year-old has four days of elevated mood, decreased need for sleep, pressured speech and reckless spending, without psychosis or hospitalisation, followed by a major depressive episode. This is hypomania, so the diagnosis is bipolar II, not bipolar I. The reasoning is duration and severity: mania requires seven days or hospitalisation, while four days with observable change but no marked impairment fits hypomania.
Traps that cost marks
Do not diagnose bipolar II from hypomania alone; a depressive episode is required. Do not miss antidepressant-induced mania. Do not call irritability alone mania without elevated mood or increased energy. Assess suicide risk at every visit, especially during mixed states and early treatment.