Biological and neuropsychological markers of cognitive dysfunction in unipolar vs bipolar Depression: What evidence do we have?

Cognition is a critical aspect of psychopathology. The aim of this review is to evaluate and discuss evidence on the biological and neuropsychological markers of cognitive dysfunction in unipolar and bipolar Depression to improve the differential diagnosis and develop plans of personalized pharmacological treatment. The different use of biological and neuropsychological markers is reviewed and their use to support the clinical process and differential diagnosis is critically examined. While biological markers can help to reduce the risk of misdiagnosis, neuropsychological markers can be assessed more readily and with a less invasive methodology. To this end, additional research on the thresholds differentiating the cognitive dysfunction in unipolar and bipolar Depression should be conducted on specific psychometric tools proposed in this review. Most importantly future effort should be directed towards the validation of both types of markers specifically for these two populations. Finally this review contributes to the field by focusing on the clinical need of a precise differential diagnosis that, when put in a translational framework, should combine an integration of research and clinical practice allowing for a better understanding of mental health and for evidence-based clinical practice.