Caffeine, Sleep, & Wakefulness: Implications of New Understanding about Withdrawal Reversal

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

2. “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!

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

4. Caffeine Withdrawal & Withdrawal Reversal Degraded due to overnight caffeine abstinence. Restoration to “normal” after caffeine. Placebo Caffeine Performance & Mood Baseline Challenge James, J. E. (1994). Neuropsychobiology, 30, 124-125.

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

6. 4.0 3.0 2.0 1.0 0 Dietary Caffeine Concentration Time Course Caffeine dose Plasma caffeine (µg/ml) Morning 24 hours Time

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

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

9. Caffeine, Sleep & Wakefulness • Caffeine, sleep & driving • Caffeine use in military operations • Restorative effects of caffeine, naps & bright light. James, J. E. & Keane, M. A. (2007).Human Psychopharmacology: Clinical & Experimental, 22, 549-558.

10. Adolescent Caffeine Use: Structural Equation Modeling (SEM)[Icelandic Centre for Social Research and Analysis (ICSRA), Reykjavik] Mother’s education Father’s education CFI = .955 RMSEA = .044 Family structure Parental education Gender r2 = .06 Smoking Licit substances Alcohol use .34 Reading Watching TV -.30 Icelandic Sitting inactive Talking Sleepiness Math -.16 Passenger car moving Passenger stationary Academic achievement English r2 = .12 Lay down to rest After a meal r2 = .19 Danish

11. Adolescent Caffeine Use: Structural Equation Modeling (SEM)[Icelandic Centre for Social Research and Analysis (ICSRA), Reykjavik] Mother’s education Father’s education CFI = .955/.950 RMSEA = .044/.040 Family structure Parental education Gender Coffee Tea r2 = .06/.23 Caffeine use Smoking Cola drinks .44 Smoking & alcohol Alcohol use Energy drinks .17 -.28 .34/.26 Reading Watching TV -.30/-.19 Icelandic Sitting inactive Talking Sleepiness Math -.16/-.12 Passenger car moving Passenger stationary Academic achievement English r2 = .12/.14 Lay down to rest After a meal r2 = .19/.25 Danish

12. 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, 32-41. James, J. E. & Gregg, M. E. (2004). Human Psychopharmacology: Clinical & Experimental, 19, 333-341. Keane, M. A., James, J. E., & Hogan, M. J. (2007). Neuropsychobiology, 56, 197-207. Keane, M. A., & James, J. E. (2008). Human Psychopharmacology: Clinical & Experimental, 23, 669-680.  • 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).