Mood Disorders


Moods are fundamental emotional states that govern internal experience and adaptive survival. Clinical disorders of mood are prevalent and emerge out of a confluence of genetic, developmental and environmental risk factors to adversely affect morbidity, mortality and function. Current clinical nosologies of mood disorders are based on a categorical rather than dimensional approach to symptomatology and have been shown to have high reliability but lack validation. Advances in the understanding of the neural circuitry underlying regulation of emotion, together with refinements in genetic analysis, neuroimaging and behavioural and biochemical assessment, have contributed to a more comprehensive view of the aetiology of mood disorders and the mechanisms of effective therapeutic interventions. Although the integration of causative factors remains incomplete, current treatment options are numerous and highly effective in the majority of cases.

Key Concepts

  • Mood and emotion are terms that have distinct connotations.
  • Mood disorders are highly prevalent and a cause of significant morbidity and mortality.
  • Mood disorders exist on a continuum of intensity and duration of mood change and can be distinguished by the presence or absence of periods of activation and mood elevation, as well as depression.
  • The underlying pathophysiology and genetic underpinnings of mood disorders are increasingly being understood.
  • Mood disorders are highly treatable, using a combination of psychotherapeutic, psychopharmacologic and/or nonpharmacologic interventions.

Keywords: depression; unipolar; bipolar; mania; mood; emotion; antidepressant

Figure 1. Expressions of grief, from Darwins's The Expression of the Emotions in Man and Animals (1872).
Figure 2. Expressions of joy, from Darwin's The Expression of the Emotions in Man and Animals (1872).
Figure 3. Portrait of melancholia, from Durer (1514).
Figure 4. Woman diagnosed with melancholia (1892). Image reproduced from Wellcome Images. Copyrighted work available under Creative Commons Attribution only licence CC BY 4.0
Figure 5. Woman diagnosed with mania (1892). Image reproduced from Wellcome Images. Copyrighted work available under Creative Commons Attribution only licence CC BY 4.0
Figure 6. Man diagnosed with persecutory mania. Image reproduced from Wellcome Images. Copyrighted work available under Creative Commons Attribution only licence CC BY 4.0


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Reus, Victor I(Apr 2017) Mood Disorders. In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1002/9780470015902.a0001484.pub3]