MD Notes

creation date: 2026-02-26 18:46
tags: Pathologies

Bipolar Disorder

Background

Definitions

Bipolar disorder refers to a mood disorder characterized by episodes that consist of mania, hypomania, and major depression.

Bipolar I disorder: experiences manic episodes and nearly always major depressive and hypomanic episodes
Bipolar II disorder: experiences at least one hypomanic episode, and at least one depressive episode, with an absence of manic episodes

Mania: clinically significant changes in mood, energy, activity, behaviour, sleep, and cognition
Hypomania: changes in mood similar to mania but less severe
Major depression: changes similar to unipolar major depression

The average age of onset for bipolar disorder is younger than major depression.

Pathogenesis

Causes of bipolar disorder are similar to major depressive disorder and are multifactoral with contributions from biological, genetic, environmental, and psychosocial factors.

While theories of the primary causes vary, they agree on downstream disturbances to neurotransmitters. Serotonin, norepinephrine, dopamine, GABA, glutamate, and glycine have all been shown to play a role.

A number of triggers may cause bipolar disorder:

  • Cannabis
  • SSRI/SNRIs
  • Prednisone

Clinical Presentation

Signs & Symptoms

Bipolar disorder can present with mania, hypomania, major depression, and mixed features (combination of symptoms of opposite polarity).

Mania and hypomania
Mania and hypomania is characterized by significant elevation in mood and energy. This is described by the mnemonic DIGFAST:

  • Distractibility
  • Indiscretion (hypersexuality, increased spending)
  • Grandiosity
  • Flight of ideas
  • Agitation (psychomotor)
  • Sleep (decreased need)
  • Talking fast

Mania is the presence of these symptoms for ≥7 days or if the severity requires hospitalization. Hypomania is if the symptoms are between 4-7 days in duration and doesn’t involve psychosis.

Major depression
Depressive episodes are described by the MSIGECAPS mnemonic:

  • Mood: depressed, can manifest as irritable
  • Sleep: insomnia or hypersomnia
  • Interest: reduced, anhedonia
  • Guilt: unrealistic (note: this is not asked unless excessive)
  • Energy: mental and physical fatigue
  • Concentration: easily distractible (note: hold this question if chief complaint may be ADHD related)
  • Appetite: decreased or increased
  • Psychomotor: retardation or agitation (note: this is observed, not asked)
  • Suicide: thoughts, plans, behaviours

History & Physical Exam

Clinical history should ascertain signs and symptoms of depression. A mental status examination should also be performed. Evaluation can be made using the PHQ-9.

Inclusion of medical, family, social, and substance use history should be done. Collateral information from family and friends will aid assessment as well.

A complete physical examination should be performed to rule out underlying causes.

Diagnosis

Criteria

Manic/hypomanic episode
Characterized by an elevated mood 3+, Symptoms include:

  • Intense prolonged happiness (e.g., for several days)
  • Irritability
  • Overconfidence, risky behavior (e.g., overspending money)
  • Decreased need for sleep
  • Hypersexuality
  • Psychotic features (only during manic episodes)

Bipolar I disorder
Bipolar I requires:

  • ≥1 manic episodes (above for ≥7 days or if hospitalization needed)
  • Functional impairment (eg. significant social or occupational dysfunction)
  • Note: depressive episode not required for diagnosis

Bipolar II disorder
Bipolar II requires:

  • ≥1 hypomanic episode (above for ≥4 days, no hospitalization nor psychosis)
  • ≥1 major depressive episode
  • Functional impairment (eg. significant social or occupational dysfunction)
  • No history of mania

Work-up

Laboratory studies

  • TSH
  • Electrolytes (particularly for hypercalcemia)
  • Basic metabolic panel (for baseline prior to therapy)
  • Urine toxicology screen

Differential

The primary differential are other mood disorders:

Other psychiatric conditions include:

General medication conditions that may result in depressive episodes or mania include:

  • CNS conditions
  • Traumatic brain injury
  • Systemic infection with HIV
  • Late neurosyphilis
  • Neurodegenerative disorders (frontatemporal dementias, Huntington disease, basal ganglia calcification)

Iatrogenic causes include:

  • ADHD treatment (stimulants)
  • Prednisone

Red Flags / Complications

Management

Acute Treatment of Mania/Hypomania

Mania is a medical emergency and should be treated promptly.

Various antimanic drugs can be used to reduce acute symptoms without switching to the opposite polarity:

  • Lithium
  • Carbamazepine
  • Valproate
  • Second generation antipsychotics (aripiprazole, cariprazine, lurasidone, olanzapine, quetiapine, risperidone)

If sedation is necessary:

  • Haloperidol
  • “Vitamin B52”: benadryl 50mg, haloperidol 5mg, lorazepam 2mg

Treatment of Bipolar Major Depression

First-line treatment consist of monotherapy of:

  • Quetiapine
  • Lurasidone

Second-line options include:

  • Olanzapine plus fluoxetine
  • Valproate monotherapy
  • Combination of quetiapine, lurasidone, or lumateperone with lithium or valproate.

Further adjustment to medication may occur depending on predominant symptom, refractory/resistance to treatment, or seasonal/cyclic patterns.

References

Tools / Guidelines

Additional Reading