DIURNAL-VARIATION OF MOOD AND NEUROPSYCHOLOGICAL FUNCTION IN MAJOR DEPRESSION WITH MELANCHOLIA

20 DSM-III-R melancholics with clinically evident diurnal symptoms and 20 controls were assessed with a battery of neuropsychological tests, a test of maximum voluntary hand-grip, and neuroendocrine measures of hypothalamic-pituitary-adrenal axis function morning and evening in a 24-h period, using a balanced design. The morning pattern of neuropsy chological impairment in the melancholics was comprehensive, affecting attention and concentration/working memory, episodic memory, reaction time and, strikingly, the speed of simultaneous match to sample, whic h was performed more slowly than the version of the task delayed to 0 or 4 s. The melancholics were significantly weaker than controls, on a measure of maximal Voluntary contraction. Significantly improved neur opsychological function was seen in the melancholic patients in the ev ening, in line with diurnal improvement in mood; there was also a larg e increase in strength. Slowing on the digit symbol substitution test, the simultaneous match to sample task, total errors on the match to s ample and hand-grip remained impaired in the evening compared to contr ols; other neuropsychological measures were no longer statistically di fferent from control values which were often worsened. Neuroendocrine measures showed significantly raised levels of cortisol and ACTH morni ng and evening in the melancholics. Morning cortisol in the melancholi cs correlated with the diurnal improvement in neuropsychological funct ioning. The results have implications for the timing of neuropsycholog ical assesment in major depression. Indices of neuropsychological and motor function may be as reliable quantitative estimates of illness se verity as subjective estimates of mood.