AN INITIAL INVESTIGATION OF BRIGHT LIGHT AND DEPRESSION - A NEUROPSYCHOLOGICAL PERSPECTIVE

The effects of bright and dim light on finger-tapping rate and on focu sed and nonfocused dichotic listening performance were evaluated in 21 nondepressed and 21 mildly depressed women. Previous research had pro posed decreased left hemisphere (LH) activation in clinically depresse d subjects, and pilot data projected a selective activating effect of ambient light on the LH. It was expected that those in the depressed g roup would have lower base rates of finger tapping, with right-hand ra tes affected most. The effect for groups was not significant. Bright l ight exposure was expected to increase the right-hand tapping rate in both groups, with a pronounced effect on depressed subjects. Group x e ffector x context interactions were not significant. Depressed subject s were expected to have a decreased right-ear advantage (REA) for dich otic consonant-vowel combinations; a main effect of groups was nonsign ificant, but in the hypothesized direction. The depressed group also f ound it more difficult, but not reliably so, to focus attention on sti muli entering the right ear. Neither group experienced the predicted i ncrease in REA in the bright light context. However, the expected incr ease in the depressed group's ability to shift focus to the right ear was seen. Longer periods of light exposure, male subjects, and clinica lly significant populations may yield statistically significant result s.