Time estimation and time production in depressive patients.

Twenty-three depressive inpatients and matched controls were studied three times at 2-week intervals. Both patients and controls initially overestimated, and subsequently approximated to, the "short" time spans (5-240 sec) whilst both correctly estimated the "long" ones (15 and 30 min) over the three occasions (Time Estimation Test, TET). There were no differences in the TET scores among the patients themselves, or between the patients and controls with the exception of one time span which the patients overestimated more than the controls. Among the depressive symptoms, only retardation was correlated with the TET scores. Similarly in the production of 30 sec (Time Production Test, TPT) there were no differences among the patients or between patients and controls. Again, only retardation was negatively correlated with the TPT score. Since the TET scores of the "short" time spans were negatively correlated with the TPT scores, it was speculated that both results derived from a single faculty, which was clinically manifested as retardation.