Can cognition screening in the clinic aid personalised treatment in bipolar disorder?

Biomarkers are essential in medicine, acting as objective indicators of physiological processes and targets for treating various medical conditions, such as high blood glucose levels in diabetes. However, the search for biomarkers in psychiatry has proved less successful. Psychiatric illnesses are classified into diagnostic categories based on a broad array of symptoms according to diagnostic criteria. Accordingly, patients diagnosed with the same psychiatric illness present great heterogeneity in their clinical presentation and shared symptoms among several psychiatric illnesses can complicate accurate diagnosis. Diagnosing and treating bipolar disorder (BD) poses challenges due to significant symptom overlap with major depressive disorder (MDD) and the frequent underreporting of hypomania symptoms. The recurrence of BD is high, even with correct diagnosis and treatment, resulting in severe impairments in patients' daily lives. Early age of illness onset, more residual depression and anxiety symptoms, and polarity of an index episode are among the most consistent clinical predictors of illness course, including recurrence, comorbidities, and time spent with symptoms (Vieta et al., 2018). However, there is a need for objective biomarkers to complement clinical observations in guiding diagnosis and predicting clinical outcomes and treatment response.