Fig. 3.

Clinical features targeted by novel antidepressant drugs based on the availability of studies investigating a specific symptom domain even as a secondary outcome. An empty box indicates no studies exploring a specific symptom, while a larger diameter of dots indicates a progressively higher number of studies. Darker shades of grey indicate a progressively higher percentage of the number of studies reporting a positive result referred to the total number of studies investigating the specific symptom. Barred dot indicates studies with negative results in the explored symptom. BUP, bupropion; DXM, dextromethorphan; NMDAR, n-methyl-d-aspartate receptor; OX-2R, orexin type 2 receptor; R, receptor.