Effects of blue light and caffeine on mood

Psychopharmacology (Berl). 2014 Sep;231(18):3677-83. doi: 10.1007/s00213-014-3503-8. Epub 2014 Mar 4.

Abstract

Rationale: Both short wavelength (blue) light and caffeine have been studied for their mood enhancing effects on humans. The ability of blue light to increase alertness, mood and cognitive function via non-image forming neuropathways has been suggested as a non-pharmacological countermeasure for depression across a range of occupational settings.

Objectives: This experimental study compared blue light and caffeine and aimed to test the effects of blue light/placebo (BLU), white light/240-mg caffeine (CAF), blue light/240-mg caffeine (BCAF) and white light/placebo (PLA), on mood.

Methods: A randomised, controlled, crossover design study was used, in a convenience population of 20 healthy volunteers. The participants rated their mood on the Swedish Core Affect Scales (SCAS) prior to and after each experimental condition to assess the dimensions of valence and activation.

Results: There was a significant main effect of light (p = 0.009), and the combination of blue light and caffeine had clear positive effects on core effects (ES, ranging from 0.41 to 1.20) and global mood (ES, 0.61 ± 0.53).

Conclusions: The benefits of the combination of blue light and caffeine should be further investigated across a range of applications due to the observed effects on the dimensions of arousal, valence and pleasant activation.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Affect / drug effects*
  • Affect / physiology
  • Arousal / drug effects*
  • Arousal / physiology
  • Attention / drug effects
  • Attention / physiology
  • Caffeine / pharmacology*
  • Central Nervous System Stimulants / pharmacology*
  • Cognition / drug effects
  • Cognition / physiology
  • Cross-Over Studies
  • Female
  • Humans
  • Light*
  • Male
  • Psychomotor Performance / drug effects
  • Psychomotor Performance / physiology
  • Young Adult

Substances

  • Central Nervous System Stimulants
  • Caffeine