Daniel J. Mullaney

Controlled trial of bright light for nonseasonal major depressive disorders

Psychotropic drug-free hospitalized veterans with nonseasonal major depressive disorders or depressed forms of bipolar disorder were treated with light for 1 week. Twenty-five patients were randomly assigned to bright white light treatment (2000-3000 lux), and 26 patients were randomized to dim red light placebo control treatment. Unlike those treated with dim red light, those treated with bright white light showed declines in three measures of depression during treatment. Partial relapse appeared within 2 days. A global depression score showed a statistically significant (p = 0.02) difference favoring bright white light treatment. Two bright-light-treated patients became mildly hypomanic, but side effects were mild. Improvement was not correlated with patient expectations; indeed, patients expected somewhat greater benefit from the placebo. Patients treated in summer responded as well as those treated in winter. Baseline electroencephalogram (EEG) sleep stage data (e.g., rapid eye movement; REM latency) did not predict treatment responses. These 1-week treatment results suggest that bright light might produce benefits for patients with nonseasonal depression. Bright light should not be recommended for routine clinical application before additional assessments with longer treatment durations are done.

An automated system for administering continuous workload and for measuring sustained continuous performance

Sustained continuous performance for up to 42 h was studied with 60 male volunteers in two separate protocols. The recuperative value of six 1-h nap breaks and a single 6-h nap break were contrasted in 20 subjects, 10 in each nap group. Forty other subjects attempted to work continuously with no breaks for 42 h. Twenty of these subjects worked simultaneously on separate parallel computer-based tasks, but worked in the same room in pairs. All subjects in the two nap groups (N=10 and N=10), as well as 20 who had no scheduled breaks, worked alone, almost isolated, with minimal interaction with the experimenters. During each 10 min, subjects performed a tracking task, a pattern-memory task, and an addition task and provided subjective ratings on sleepiness and attention/fantasy. Results showed that computerized tasks demanding sustained continuous performance without naps cause more rapid performance deterioration than previously tested intermittent-work paradigms.

EFFECTS OF SUSTAINED CONTINUOUS PERFORMANCE ON SUBJECTS WORKING ALONE AND IN PAIRS

Sustained continuous performance for up to 42 hr. was studied with 30 male volunteers. During each 10 min., subjects performed a tracking task, a pattern-memory task, an addition task, and provided subjective ratings on sleepiness and attention-fantasy scales plus a brief written description summarizing their thoughts. Of the 10 subjects required to work alone, 4 did not complete the 42 hr. and 9 experienced “psychological events” such as hallucinations, visual illusions, and disorientation. Of the 20 subjects who began the 42-hr. task in pairs, 5 did not complete the 42 hr. and 13 experienced similar psychological events. The percentage who did not complete the 42 hr. of the study and the incidence of psychological events were not significantly different for subjects working alone and in pairs. Performance results were very similar. No significant relationship of psychological events to any of the performance measures was demonstrated. These results indicate that continuous sustained performance produces rapid deterioration of performance and psychological disturbances, regardless of the presence or absence of social contact.