Biological markers of depression

The recent advances in molecular genetics It is now feasible to use molecular techniques to study the functional expression of specific genes associated with clearly defined marker abnormalities in patients with depression. Such studies could yield valuable information regarding the classification and aetiology of depressive disorder and would be a valuable approach to complement linkage study. While linkage study alone has the potential to demonstrate an association between a small area of the genome and a clinical diagnosis, it offers no information about disease mechanisms at the molecular level. Our present ability to conduct innovative functional molecular investigations is limited principally by the difficulty of demonstrating reliable biological abnormalities in groups of depressed patients.