Overview of Mood Disorders

Depression

A major depressive episode is defined as having ≥ 5 of the following symptoms during the same 2-week period, of which at least 1 of the symptoms is depressed mood or loss of interest or pleasure. With the exception of suicidal thoughts or attempts, all symptoms are present nearly every day (1):

• Depressed mood most of the day

• Markedly diminished interest or pleasure in all or almost all activities for most of the day

• Significant weight gain or loss (eg, a change of >5% of body weight in a month) or decreased or increased appetite

• Insomnia (often sleep-maintenance insomnia) or hypersomnia

• Psychomotor agitation or retardation observed by others (not self-reported)

• Fatigue or loss of energy

• Feelings of worthlessness or excessive or inappropriate guilt

• Diminished ability to think or concentrate or indecisiveness

• Recurrent thoughts of death or suicide, a suicide attempt, or specific plan for suicide

See below for further information and diagnostic criteria for depressive disorders (1).

Mania

A manic episode is defined as having an abnormally and persistently elevated, expansive, or irritable mood, and increased activity or energy that lasts for ≥ 1 week (or less if hospitalization is necessary) plus ≥ 3 additional symptoms (or ≥ 4 if the mood is only irritable) (1):

• Inflated self-esteem or grandiosity

• Decreased need for sleep

• More talkativeness than usual or pressure to keep talking

• Flight of ideas or racing of thoughts

• Distractibility

• Increased goal-directed activity or psychomotor agitation

• Excessive involvement in activities with high potential for painful consequences (eg, buying sprees, foolish business investments, sexual indiscretions)

The presence of psychotic features indicates a more extreme manifestation of mania that is characterized by psychotic symptoms that may be difficult to distinguish from schizophrenia. Patients may have extreme grandiose or persecutory delusions (eg, of being Jesus or being pursued by the FBI), occasionally with hallucinations. Activity level increases markedly; patients may race about and scream, swear, or sing. Mood lability increases, often with increasing irritability. Full-blown delirium (delirious mania) may appear, with complete loss of coherent thinking and behavior.

See below for further information and diagnostic criteria for bipolar disorders.

Hypomania

A hypomanic episode is a variant of a manic episode that is of shorter duration and often has less severe symptoms. A hypomanic episode is defined as a distinct period of an abnormally and persistently elevated, expansive, or irritable mood and increased activity or energy that are present for most of the day, nearly every day. The episode lasts ≥ 4 days and includes ≥ 3 of the additional symptoms listed above in the definition of a manic episode (1). Even if a hypomanic episode lasts a week or longer, it does not result in marked impairment, psychotic features, or hospitalization.

Mixed features

An episode of mania or hypomania is designated as having mixed features (of both mania and depression) if ≥ 3 depressive symptoms are present for most days of the episode. This condition is often difficult to diagnose and may shade into a continuously cycling state; the prognosis is then worse than that in a pure manic or hypomanic state (1).

Risk of suicide during mixed episodes is particularly high (2, 3).

Similarly, a major depressive episode has mixed features if ≥ 3 manic symptoms are present for most days of the episode. Depressive episodes with mixed features are a significant risk factor for development of bipolar I or bipolar II disorder (1).

Symptoms and signs references

1. 1. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, 5th ed, Text Revision. American Psychiatric Association Publishing; 2022.

2. 2. Sverdlichenko I, Jansen K, Souza LDM, da Silva RA, Kapczinski F, Cardoso TA. Mixed episodes and suicide risk: A community sample of young adults. J Affect Disord. 2020;266:252-257. doi:10.1016/j.jad.2020.01.111

3. 3. Carvalho AF, Firth J, Vieta E. Bipolar Disorder. N Engl J Med. 2020;383(1):58-66. doi:10.1056/NEJMra1906193

Suicide in mood disorders

Suicide is a significant risk in people with mood disorders. Patients with major depressive disorder or bipolar disorder are 8 to 9 times more likely to die by suicide than the general population (1). Lifetime risk of suicide for people with a depressive disorder is 3 to 8%, depending on the severity of their depression (2, 3). In patients with bipolar disorder, the lifetime risk of suicide is 5 to 6% (4).

Factors associated with increased risk of suicide in people with mood disorders include history of prior suicide attempts, particularly with a violent method; recent initiation of antidepressant medications, particularly in adolescents or young adults; presence of psychotic features; anxiety; sleep disturbance; and substance misuse (5–7). (See Antidepressants and Suicide Risk.)

Other complications or comorbidities of mood disorders

Complications of mood disorders include:

• Impaired function ranging from mild to complete inability to function, maintain social interaction, or participate in routine activities

• Impaired food intake, sometimes resulting in significant weight loss or gain

• Severe anxiety

• Alcohol use disorder

• Other substance use disorders

• Immune suppression and increased cardiovascular risk with depression (see Depressive Disorders)

If anxiety disorders such as generalized or panic disorder fully manifest between mood disorder episodes, they can be viewed as comorbidities.

Comorbidities and complications references

1. 1. Arnone D, Karmegam SR, Östlundh L, et al. Risk of suicidal behavior in patients with major depression and bipolar disorder - A systematic review and meta-analysis of registry-based studies. Neurosci Biobehav Rev. 2024;159:105594. doi:10.1016/j.neubiorev.2024.105594

2. 2. Aaltonen KI, Isometsä E, Sund R, Pirkola S. Risk factors for suicide in depression in Finland: first-hospitalized patients followed up to 24 years. Acta Psychiatr Scand. 2019;139(2):154-163. doi:10.1111/acps.12990

3. 3. Isometsä ET. Suicides in Mood Disorders in Psychiatric Settings in Nordic National Register-Based Studies. Front Psychiatry. 2020;11:721. Published 2020 Jul 23. doi:10.3389/fpsyt.2020.00721

4. 4. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, 5th ed, Text Revision. American Psychiatric Association Publishing; 2022.

5. 5. Lundberg J, Cars T, Lampa E, et al. Determinants and Outcomes of Suicidal Behavior Among Patients With Major Depressive Disorder. JAMA Psychiatry. 2023;80(12):1218-1225. doi:10.1001/jamapsychiatry.2023.2833

6. 6. Gournellis R, Tournikioti K, Touloumi G, et al. Psychotic (delusional) depression and suicidal attempts: a systematic review and meta-analysis. Acta Psychiatr Scand. 2018;137(1):18-29. doi:10.1111/acps.12826

7. 7. Riera-Serra P, Navarra-Ventura G, Castro A, et al. Clinical predictors of suicidal ideation, suicide attempts and suicide death in depressive disorder: a systematic review and meta-analysis. Eur Arch Psychiatry Clin Neurosci. 2024;274(7):1543-1563. doi:10.1007/s00406-023-01716-5