Bipolar Disorder

Bipolar disorder is a chronic, episodic mood disorder. It is characterised by manic or hypomanic episodes, typically together with intervening or accompanying depressive episodes.

Bipolar I disorder requires at least one full manic episode. Depressive episodes frequently, though not invariably, also occur. Bipolar II disorder requires at least one hypomanic episode and at least one major depressive episode, without any full manic episode.

Accurate diagnosis, and specifically distinction from unipolar major depressive disorder, carries critical treatment implications. Antidepressant monotherapy without adequate mood stabilising cover can precipitate or worsen mania, or induce rapid cycling between mood states, in a patient with unrecognised bipolar disorder.

Pathophysiology and classification

• The pathophysiology reflects a complex interplay of strong genetic predisposition and neurobiological factors affecting mood regulation circuitry. Bipolar disorder shows among the highest heritability of the major psychiatric conditions. The complete mechanism remains an area of ongoing research.
• Manic episodes are a distinct period of abnormally and persistently elevated, expansive or irritable mood together with increased energy or activity. The period lasts at least one week (or any duration if hospitalisation is required).
• Associated manic symptoms include grandiosity, decreased need for sleep, pressured speech, flight of ideas, distractibility, increased goal directed activity or psychomotor agitation, and activities with high potential for painful consequences (including significant, sometimes catastrophic financial, sexual or other impulsive, high risk behaviour).
• Severity is sufficient to cause marked functional impairment or to require hospitalisation, or psychotic features are present.
• Hypomanic episodes share a similar symptom profile to mania but with lower severity and a shorter minimum duration (four days rather than one week). They lack the marked functional impairment, need for hospitalisation, or psychotic features that would indicate a full manic episode. This distinction determines whether bipolar I or bipolar II disorder is the appropriate classification.
• Rapid cycling is four or more distinct mood episodes within a twelve month period. Mixed features are the simultaneous presence of manic/hypomanic and depressive symptoms within the same episode.
• Both are recognised, clinically important specifiers relevant to treatment selection. They generally indicate a more complex, treatment resistant course.

• Manic episodes present with elevated or irritable mood, increased energy, decreased need for sleep, grandiosity, pressured speech, racing thoughts, distractibility, and impulsive, high risk behaviour. Grandiosity may reach delusional intensity in severe episodes with psychotic features.
• Severity and associated functional impairment or psychotic features distinguish a full manic episode from the milder hypomanic presentation.
• Depressive episodes in bipolar disorder share the core symptom profile of major depressive disorder, described under that condition. Certain features are somewhat more suggestive, though not diagnostic in isolation, of a bipolar rather than unipolar depressive process. These include a somewhat greater tendency toward atypical features such as hypersomnia and increased appetite, and a younger typical age of onset.
• Screen carefully and directly for any prior history of hypomanic or manic symptoms in every patient presenting with a depressive episode.
• Patients frequently seek treatment predominantly, or exclusively, during depressive episodes, because depression is more distressing and prompts help seeking. Hypomania or early mania is frequently euphoric and less likely to prompt help seeking.
• Without systematic, targeted screening, bipolar disorder is frequently substantially underdiagnosed or diagnosed only after a significant delay.
• Significant functional impairment occurs across occupational, financial, relationship and social domains. It reflects the impulsive, high risk behaviour of manic and, to a lesser extent, hypomanic episodes.
• Suicide risk is substantial, notably elevated during depressive episodes and, importantly, mixed feature episodes. Assess it carefully.

• Full clinical psychiatric assessment is the essential diagnostic approach. Explore in detail any prior episodes of elevated, expansive or irritable mood, with associated features, duration, severity and functional impact.
• Collateral history from family members or other close contacts, where the patient consents, frequently provides valuable additional information. Patients frequently show reduced insight into the abnormal nature of their mood state during manic or hypomanic episodes.
• Screen for and exclude substance induced mood disturbance. Stimulants and, in some cases, corticosteroid medication can produce a manic or hypomanic like presentation.
• Screen for and exclude an underlying medical cause, including hyperthyroidism, which can produce symptoms with some clinical overlap with hypomania.
• Structured mood charting, where feasible, supports longitudinal characterisation of the pattern and frequency of mood episodes over time. It aids both diagnostic confirmation and ongoing treatment monitoring.
• Full suicide risk assessment, covered separately, is an essential, integral component of assessment across all phases of this condition. Risk is substantial, particularly during depressive and mixed feature episodes.

• Mood stabilising medication is the cornerstone of both acute and long term maintenance treatment.
• Lithium is a well established, effective agent for both acute mania and long term maintenance treatment. Additional evidence supports a particular reduction in suicide risk with long term lithium maintenance, a notable distinguishing feature of this agent.
• Lithium has a narrow therapeutic index and requires regular monitoring of serum levels. Monitor renal and thyroid function too, given recognised longer term effects on these systems with sustained treatment.
• Sodium valproate and certain atypical antipsychotics (including quetiapine, olanzapine, and others) are further effective options for acute mania and, for several of these agents, maintenance treatment.
• Individualise agent selection according to clinical presentation, prior treatment response, tolerability and patient factors.
• Avoid sodium valproate in women of childbearing potential, or use it with extreme caution and only with robust, effective contraception, given significant teratogenic risk.
• Lamotrigine has specific evidence of efficacy for the depressive phase and maintenance treatment of bipolar disorder, but lacks efficacy for acute mania. Its role is as a component of longer term maintenance treatment, particularly where depressive episodes are a prominent part of the illness course, not for acute manic episode management.
• Antidepressant medication, where used for the depressive phase, should generally only be introduced alongside an adequate, established mood stabilising agent. Antidepressant monotherapy carries a substantial, well recognised risk of precipitating a manic switch or inducing rapid cycling.
• This is one of the most clinically important reasons why accurate distinction between unipolar and bipolar depression matters for treatment.
• Acute severe mania warrants consideration of inpatient psychiatric admission when there are psychotic features, significant risk to self or others, or functional impairment precluding safe community management. Antipsychotic medication, frequently at a higher dose than used for maintenance, is commonly required for rapid symptom control.
• Psychoeducation is an important, evidence based adjunct to pharmacological treatment. It covers illness recognition (including early warning signs of an emerging mood episode, supporting earlier intervention).
• Psychoeducation also addresses medication adherence. Relapse risk is substantial with treatment discontinuation, and ambivalence toward maintenance treatment is common, particularly during periods of stability or during hypomanic episodes when the patient may not perceive their mood state as problematic.
• Lifestyle factors matter, particularly regular sleep patterns, because sleep disruption is both a symptom and a potential trigger for mood episodes.
• Structured psychological therapy, including cognitive behavioural therapy adapted for bipolar disorder and family focused therapy, is also an important adjunct.
• Full, structured, long term multidisciplinary management underpins effective care of this chronic, relapsing condition. It includes regular psychiatric follow up, ongoing medication monitoring, and systematic, ongoing suicide risk assessment.
• The goals are acute episode treatment and, of at least equal importance, sustained long term maintenance treatment. This aims to prevent relapse and minimise the substantial cumulative functional and psychosocial impact of recurrent mood episodes over the patient's life.