Personality and the modulation of effects of sleep loss on mood and cognition

Participants (n=31, males=15, females=16, mean age=21.4 years) deprived of sleep for 29-35 h showed significant deficits on logical reasoning and on b ipolar Profile Of Mood States total mood. Deficits in mood due to sleep los s correlated significantly with neuroticism, extraversion and usual sleep d uration, and there was a statistically significant quadratic function of mo od change with locus of control (LOC) score, such that internals and extrem e externals had a smaller mood deficit after sleep loss than did moderate e xternals. internals had been hypothesised from previous work to be less aff ected by stresses, including sleep loss, and we suggest that extreme extern als may have been more susceptible to the positive motivating effects of th e research assistants and the sleep laboratory environment, including invol vement in various sociable leisure activities. Regression analysis showed t hat the only significant personality predictors of change in total mood wer e neuroticism (beta = -0.40) and the quadratic function of LOC (beta= 0.39) . Change in logical reasoning performance was significantly correlated with change in total mood (r = 0.36): but with none of the personality variable s. (C) 2001 Elsevier Science Ltd. All rights reserved.