Precision biomarkers for mood disorders based on brain imaging

Abstract

Mood disorders are a global public health problem because of their high prevalence, chronicity, and recurrence throughout the lifespan as well as increased risk of mortality.123 They also impose a heavy economic burden on society because of lost work productivity (occupational disability) and increased use of health services.4 Early diagnosis and effective treatment are therefore essential. Mood disorders are characterised by a significant change in a person’s state of mood and include two main subtypes: depressive disorders (major depressive episode and dysthymia) and bipolar disorders (hypomania, mania, or cyclothymia—that is, cycling between depressed and manic states). In 2015, over 300 million people were living with major depressive disorder worldwide, representing 4.4% of the global population.5 A world mental health survey reported that the lifetime and 12 month prevalences of bipolar disorders in the general population were 2.4% and 1.5%, respectively.6 Mood disorders are associated with a widespread cognitive dysfunction, involving higher-order executive function,7 reward processing,8 and emotional regulation (fig 1, box 1).10 These deficits are associated with abnormalities in both the structure and function of specific brain circuits. Interest is growing in developing precision biomarkers for mood disorders based on a deeper understanding of their biological bases by integrating multilevels of data, such as brain imaging, clinical symptoms, and cognitive behaviours.1112