Anhedonia Relates to Increased Psychomotor Retardation Using an Instrumental Handwriting-Based Measure.

Psychomotor retardation (PmR) is a clinically important but understudied feature of depression. Available studies of PmR in depression have also been limited by the reliance on self-report and observation. Instrumental measures, which have been used to assess motor symptoms in neurological disorders, exhibit greater precision and sensitivity than self-report measures and can provide vital information in the clinical presentation. Hence, the present study sought to examine (a) whether depression (diagnosis and/or symptoms) is abnormally associated with an instrumental-based indictaor of PmR, velocity scaling (VS), a behavioral metric that reflects the ability to increase rate of movement across longer versus shorter distances, and (b) the reliability (internal consistency) of VS. A large sample of healthy controls (n = 85) and those with lifetime MDD (n = 146), completed a handwriting task on a tablet. VS was quantified as a slope of change in velocity from 1 to 4 cm hand-drawn loops, with steeper slopes indicating less PmR. Whereas VS did not differ between groups, lower VS was significantly negatively related to greater anhedonia across participants, even after covarying for overall depression severity. VS scores also exhibited excellent internal consistency. The handwriting task is a reliable and brief measure that can be completed in only a few minutes and could be a feasible way to assess for PmR in clinical settings. Future studies are needed to determine the temporal relation between VS and anhedonia.

Supplementary information: The online version contains supplementary material available at 10.1007/s10862-025-10249-1.