The effect of mild depression on time discrimination.

Depressed mood states affect subjective perceptions of time but it is not clear whether this is due to changes in the underlying timing mechanisms, such as the speed of the internal clock. In order to study depression effects on time perception, two experiments using time discrimination methods with short (<300 ms) and long (>1000 ms) durations were conducted. Student participants who were categorised as mildly depressed by their scores on the Beck Depression Inventory were less able than controls to discriminate between two longer durations but were equally able to discriminate shorter intervals. The results suggest that mildly depressed or dysphoric mood do not affect pacemaker speed. It is more likely that depression affects the ability to maintain attention to elapsing duration.