Caffeine, Sleep, & Wakefulness: Implications of New Understanding about Withdrawal Reversal Neuroscience Center Rockville, Maryland July 2009 Jack James, PhD School of Psychology National University of Ireland, Galway Caffeine: Is the Next Problem Already Brewing? NIDA-ODS Symposium

“A health advice service has been set up as part of a Health Board drug prevention initiative.” Health Board Café for young people: Learn About the Dangers of Drugs as You Relax with a Coffee!

Common Beliefs & Claims about Caffeine Enhances performance & mood. Encourages wakefulness.

Baseline Challenge Performance & Mood Placebo Caffeine Degraded due to overnight caffeine abstinence. Restoration to “normal” after caffeine. Caffeine Withdrawal & Withdrawal Reversal James, J. E. (1994). Neuropsychobiology, 30,

Withdrawal Reversal Hypothesis Caffeine abstinence negatively affects performance & mood, which are restored (withdrawal reversal) when caffeine is next ingested.

Plasma caffeine (µg/ml) Dietary Caffeine Concentration Time Course Morning Time 24 hours Caffeine dose

Main Research Design Options for Controlling Confounding Due to Withdrawal Relief 1.Consumers versus low/non-consumers. 2.Pre-treatment or ad lib consumptions. 3.Long-term withdrawal.

placebo caffeine ‘caffeine abstinent’ ‘acute challenge’ ‘withdrawal’ ‘dietary use’ placebo caffeine placebo caffeine Research Design: Controlling for Withdrawal Reversal ‘Run-in’‘Challenge’ (1-6 days)(7th day) Condition James, J. E., & Rogers, P. J. (2005). Psychopharmacology, 182, 1-8.

Caffeine, Sleep & Wakefulness James, J. E. & Keane, M. A. (2007). Human Psychopharmacology: Clinical & Experimental, 22, Caffeine, sleep & driving Caffeine use in military operations Restorative effects of caffeine, naps & bright light.

Father’s education Parental education Adolescent Caffeine Use: Structural Equation Modeling (SEM) [Icelandic Centre for Social Research and Analysis (ICSRA), Reykjavik] Mother’s education Watching TV Talking Family structure Gender Passenger stationary After a meal Reading Sitting inactive Passenger car moving Lay down to rest Smoking Alcohol use Icelandic Math English Danish Academic achievement Licit substances Sleepiness CFI =.955 RMSEA =.044 r 2 =.06 r 2 =.12 r 2 =

Father’s education Parental education Mother’s education Watching TV Talking Family structure Gender Passenger stationary After a meal Reading Sitting inactive Passenger car moving Lay down to rest Smoking Alcohol use Coffee Tea Cola drinks Energy drinks Icelandic Math English Danish Caffeine use Academic achievement Smoking & alcohol Sleepiness CFI =.955/.950 RMSEA =.044/.040 r 2 =.06/.23 r 2 =.12/.14 r 2 =.19/.25.34/ / / Adolescent Caffeine Use: Structural Equation Modeling (SEM) [Icelandic Centre for Social Research and Analysis (ICSRA), Reykjavik]

Summary of Main Findings: Caffeine, Sleep & Wakefulness Sleep restriction has adverse effects on aspects of performance and mood. After controlling for withdrawal reversal, dietary caffeine has ·Little or no net gains for performance or mood. ·Little or no restorative effects (following sleep loss) for performance or mood. ·May exacerbate the negative effects of sleep loss. James, J. E. (1998). Neuropsychobiology, 38, James, J. E. & Gregg, M. E. (2004). Human Psychopharmacology: Clinical & Experimental, 19, Keane, M. A., James, J. E., & Hogan, M. J. (2007). Neuropsychobiology, 56, Keane, M. A., & James, J. E. (2008). Human Psychopharmacology: Clinical & Experimental, 23, Inference ·Rather than enhancing “alertness” & “arousal”, a main biobehavioral effect of caffeine may be to disrupt sleep & attentional processes (previously masked by failure to control for withdrawal reversal).