Bipolar Disorder

Definition | Aetiology | Pathophysiology | Risk factors | Signs and symptoms | Investigations | Management

Definition

Bipolar Disorder is a chronic psychiatric condition characterised by recurrent episodes of mania and depression, significantly impacting mood, behaviour, and daily functioning.

Aetiology

  • Genetic factors: strong hereditary component with multiple risk-associated genes.
  • Neurochemical imbalances: dysregulation of dopamine, serotonin, and noradrenaline.
  • Neurobiological abnormalities: altered limbic system activity and prefrontal cortex dysfunction.
  • Psychosocial factors: stress, trauma, sleep disturbances, and lifestyle factors.

Pathophysiology

  • Abnormal neurotransmitter regulation, particularly dopamine and serotonin.
  • Increased activity in limbic structures during manic episodes.
  • Reduced grey matter volume in the prefrontal cortex, affecting mood regulation.
  • Disruptions in circadian rhythm and sleep-wake cycle.

Risk factors

  • Family history of bipolar disorder or other mood disorders.
  • Early life trauma or adverse experiences.
  • Substance misuse (e.g., stimulants, alcohol, cannabis).
  • Significant psychosocial stressors.
  • Sleep disturbances or circadian rhythm dysfunction.

Signs and symptoms

  • Manic episodes:
    • Euphoric or irritable mood.
    • Increased energy and reduced need for sleep.
    • Racing thoughts, pressured speech.
    • Grandiosity and inflated self-esteem.
    • Risk-taking behaviour (e.g., excessive spending, substance use).
  • Depressive episodes:
    • Persistent low mood and anhedonia.
    • Fatigue, hypersomnia or insomnia.
    • Feelings of worthlessness or excessive guilt.
    • Difficulty concentrating or making decisions.
    • Suicidal ideation or self-harm.
  • Mixed episodes: features of both mania and depression occurring simultaneously.

Investigations

  • Comprehensive psychiatric assessment: history and mental state examination.
  • Structured diagnostic tools: Mood Disorder Questionnaire (MDQ), Young Mania Rating Scale (YMRS).
  • Collateral history: from family, friends, or caregivers.
  • Blood tests: FBC, U&Es, LFTs, TFTs, vitamin B12, folate to exclude organic causes.
  • Urine drug screen: to rule out substance-induced mood symptoms.
  • Neuroimaging (MRI/CT): if neurological pathology suspected.

Management

1. Pharmacological management:

  • Acute mania:
    • First-line: Atypical antipsychotics (e.g., olanzapine, risperidone, quetiapine).
    • Second-line: Mood stabilisers (e.g., lithium, valproate).
    • Short-term benzodiazepines for severe agitation.
  • Depressive episodes:
    • Quetiapine or lamotrigine.
    • Antidepressants are used cautiously and usually in combination with a mood stabiliser.
  • Long-term maintenance:
    • Lithium as first-line prophylactic treatment.
    • Valproate or lamotrigine as alternatives.

2. Psychological and social interventions:

  • Cognitive Behavioural Therapy (CBT) for relapse prevention.
  • Interpersonal and social rhythm therapy to stabilise mood.
  • Family-focused therapy and psychoeducation.

3. Lifestyle modifications:

  • Regular sleep routine to stabilise circadian rhythms.
  • Avoidance of stimulants and alcohol.
  • Stress management techniques.

4. Crisis and referral management:

  • Crisis team referral: if acute suicidal risk.
  • Community mental health team (CMHT): for long-term follow-up.
  • Hospital admission: if severe mania or suicidality.
PsychiatrymypanotesBipolar Disorder