Mood Disorders
What this domain tests
This domain tests accurate episode counting, the bipolar screen before any antidepressant, specifier use, and evidence-based maintenance planning - the areas where candidates most often lose easy marks.
Core rules and concepts
- Major depressive episode: five of nine symptoms for two weeks or more, including depressed mood or anhedonia.
- Bipolar I: at least one manic episode (one week or more, or hospitalisation) with marked impairment. Bipolar II: hypomania of four days or more plus major depression, never mania.
- Specifiers: mixed features (three subthreshold opposite-pole symptoms), rapid cycling (four or more episodes in twelve months), psychotic features, peripartum, seasonal pattern.
- Treatment: moderate to severe unipolar depression - SSRI plus CBT; continue for six to twelve months after remission, and two years or more if recurrent. Lithium remains the first-line mood stabiliser and has anti-suicidal evidence; monitor levels twelve hours post-dose, typically 0.6–0.8 mmol/L for maintenance, with renal and thyroid checks.
- Bipolar depression: avoid antidepressant monotherapy; valproate is teratogenic and should be avoided in women of childbearing potential where alternatives exist; lamotrigine must be titrated slowly.
- ECT is indicated for severe, psychotic, catatonic or life-threatening episodes and for treatment resistance.
Worked example
A 30-year-old reports two weeks of low mood, anhedonia, insomnia, guilt, poor concentration and passive death wish, with no lifetime hypomania. That is six symptoms of a major depressive episode of moderate severity. The next step is an SSRI with CBT, psychoeducation about activation and suicide risk, and review within two weeks.
Traps that cost marks
- Diagnosing major depressive disorder without screening for past hypomania.
- Antidepressant monotherapy in bipolar disorder.
- Quoting lithium levels without stating the sampling time.