ABSTRACT
Genetic and Neurophysiological Substrates 36
A Theoretical Model of Arousal and Caffeine 37
Cognition and Performance 37
Psychomotor Functions 37
Vigilance 38
Selective Attention 38
Memory 39
Effects of Caffeine on Mood 39
Alertness 40
Positive Mood States 40
Complications and Caveats 40
Caffeine Abuse and Dependence 41
Caffeine Dependence 41
Epidemiology 41
Caffeine Intoxication 42
Caffeine and Anxiety Disorders 43
The Role of Caffeine in Other Disorders 43
Psychopharmacological Treatment: Caffeine Interactions 44
Caffeine and Pain 45
References
INTRODUCTION
The biobehavioral effects of caffeine on psychological functioning and behavior are mediated by underlying genetic mechanisms and their neurophysiological expressions. Primarily by blocking adenosine A2A receptors, caffeine affects cognitive and psychomotor functions and mood states. A multidimensional, biobehavioral arousal model explains a number of these effects. The drug tends to decrease reaction times and improve vigilance performance, though its effects on memory are poorly understood. Caffeine increases alertness, the psychological representation of physiological arousal, and, in low-to-moderate doses, increases positive mood states. High doses can produce negative affect, but there is considerable individual variability in caffeine sensitivity, based on genetic predispositions and prior experience. Available statistics suggest that caffeine dependence and abuse may be quite widespread, in some cases producing caffeine intoxication (caffeinism) and exacerbating some anxiety disorders. Caffeine effects are also seen in depression, schizophrenia, eating disorders, attention deficit hyperactivity disorder (ADHD), and restless legs syndrome (RLS).
