Synopsis
Recognise depression within a bipolar course, retrieve lifetime evidence of activation before choosing treatment, exclude important medical and substance mimics, and manage current severity without waiting for perfect retrospective certainty.
- Bipolar depression can look identical to unipolar depression in cross-section; diagnosis depends on the lifetime course, not a special depressive symptom checklist.
- Ask every depressed adult about previous overactivity, disinhibition, elevated or irritable mood, reduced sleep need, increased speech, projects, spending and treatment-related activation.
- NICE advises considering specialist assessment when previous overactivity or disinhibition lasted four days or more and urgent referral for suspected mania, severe depression or danger.
- Retrieve records and agreed collateral because past hypomania may have felt productive, occurred years earlier or been forgotten during the present low mood.
- Assess current suicide risk, psychosis, catatonia, mixed activation, self-care, dependants, substances and access to medication before focusing on diagnostic terminology.
- Check thyroid, anaemia, sleep, neurological, reproductive, medicine and substance explanations selectively from the history and examination; routine tests do not diagnose bipolar disorder.
- For moderate or severe bipolar depression without current bipolar medication, NICE offers fluoxetine with olanzapine or quetiapine alone, with olanzapine alone or lamotrigine as preference-sensitive alternatives.
- If lithium is already prescribed, check the plasma concentration and optimise an inadequate level before adding the NICE-recommended depressive treatment selected with the patient.
- Monitor for emerging hypomania, worsening depression, adverse effects and suicide risk, and limit quantities where overdose toxicity is a material concern.
Key red flags
Suicidal preparation, access to lethal means, recent self-harm, severe hopelessness or an agitated mixed state requires immediate individual formulation and intervention.
Reduced sleep need, racing thoughts, agitation and impulsivity during apparent depression may indicate mixed features and greater capability for harmful action.
Delusions of guilt, poverty, bodily non-existence or deserved punishment, accusatory voices or catatonic signs indicate severe bipolar depression requiring urgent specialist care.
Confusion, fluctuating attention, focal neurology, fever, new seizure or abrupt late-life onset suggests delirium or neurological disease rather than an uncomplicated mood episode.
Depression, insomnia, irritability or psychosis arising during pregnancy or after birth requires rapid perinatal assessment and medication-risk review.
Investigation priorities
Map depressive, elevated, irritable and mixed periods, inter-episode recovery, duration, triggers and functional consequences.
Management branches
Current depression is accompanied by previous activation, disinhibition or reduced sleep need.
- Establish current severity, suicide risk, psychosis and mixed features and provide urgent care first when danger or severe illness is present.
- Build a lifetime timeline using behavioural examples, records and consented collateral and review substances, medicines and medical explanations.
- Seek specialist bipolar assessment and agree interim safety, sleep and treatment plans that include monitoring for activation and clear escalation routes.