548 Flaten MA, Blumenthal TD (1999) Caffeine associated stimuli elicit conditioned responses: an experimental model of the placebo effect. Psychopharmacology 145:105–112 Flaten MA, Simonsen T, Olsen H (1999) Drug-related information generates placebo and nocebo responses that modify the drug response. Psychosom Med 61:250–255 Flaten MA, Simonsen T, Zahlsen K, Aamo T, Sager G, Olsen H (2004) Stimulant and relaxant drugs combined with stimulant and relaxant information: a study of active placebo. Psychopharmacology 176:426–434. doi:10.1007/s00213-004-1886-7 GarciaLarrea L, Peyron R, Laurent B, Mauguiere F (1997) Association and dissociation between laser-evoked potentials and pain perception. NeuroReport 8:3785–3789 Granovsky Y, Granot M, Nir RR, Yamitsky D (2008) Objective correlate of subjective pain perception by contact heat-evoked potentials. J Pain 9:53–63. doi:10.1016/j.jpain.2007.08.010 Gratton G, Coles MGH, Donchin E (1983) A new method for off-line removal of ocular artifact. Electroencephalogr Clin Neurophysiol 55:468–484 Greenberg RP, Fisher S (1994) Suspended judgement seeing through the double-masked design: a commentary. Control Clin Trials 15:244–246 Iannetti GD, Hughes NP, Lee MC, Mouraux A (2008) Determinants of laser-evoked EEG responses: pain perception or stimulus saliency? J Neurophysiol 100:815–828. doi:10.1152/jn.00097.2008 Keogh E, Witt G (2001) Hypoalgesic effect of caffeine in normotensive men and women. Psychophysiology 38:886–895. doi:10.1111/ 1469-8986.3860886 Khalsa SS, Rudrafu D, Sandesara C, Olshansky B, Tranel D (2009) Bolus isoproterenol infusions provide a reliable method for assessing interoceptive awareness. Int J Psychophysiol 72:34–45. doi:10.1016/j.ijpsycho.2008.08.010 Kirsch I, Sapirstein G (1998) Listening to Prozac but hearing placebo: a meta-analysis of antidepressant medication. In: Kirsch I (ed) How expectancies shape experience. American Psychological Association, Washington, DC, pp 303–320 Lautenbacher S, Kunz M, Burkhardt S (2008) The effects of DNIC- type inhibition on temporal summation compared to single pulse processing: does sex matter? Pain 140:429–435. doi:10.1016/j. pain.2008.09.019 Leandri M, Saturno M, Spadavecchia L, Iannetti GD, Cruccu G, Truini A (2006) Measurement of skin temperature after infrared laser stimulation. Neurophysiol Clin 36:207–218. doi:10.1016/j. neucli.2006.08.004 Lyerly SB, Ross S, Krugman AD, Clyde DJ (1964) Drugs and placebos—the effects of instructions upon performance and Psychopharmacology (2011) 215:537–548 mood under amphetamine sulfate and chloral hydrate. J Abnorm Soc Psychol 68:321–327 Mikalsen A, Bertelsen B, Flaten MA (2001) Effects of caffeine, caffeine-associated stimuli, and caffeine-related information on physiological and psychological arousal. Psychopharmacology 157:373–380 Moncrieff J (2003) A comparison of antidepressant trials using active and inert placebos. Int J Method Psych 12:117–127 Morton DL, El-Deredy W, Watson A, Jones AKP (2010) Placebo analgesia as a case of a cognitive style driven by prior expectation. Brain Res 1359:137–141. doi:10.1016/j.brainres.2010.08.046 Mouraux A, Iannetti GD (2009) Nociceptive laser-evoked brain potentials do not reflect nociceptive-specific neural activity. J Neurophysiol 101:3258–3269. doi:10.1152/jn.91181.2008 O'Neill ST, Parrott AC (1992) Stress and arousal in sedative and stimulant cigarette smokers. Psychopharmacology 107:442– 446 Parrott AC (1993) Cigarette smoking: effects upon self-rated stress and arousal over the day. Addict Behav 18:389–395 Pud D, Granovsky Y, Yarnitsky D (2009) The methodology of experimentally induced diffuse noxious inhibitory control (DNIC)-like effect in humans. Pain 144:16–19. doi:10.1016/j. pain.2009.02.015 Ross S, Krugman AD, Lyerly SB, Clyde DJ (1962) Drugs and placebos—a model design. Psychol Rep 10:383–392 Silverman K, Griffiths RR (1992) Low-dose caffeine discrimination and self-reported mood effects in normal volunteers. J Exp Anal Behav 57:91–107 Staud R, Robinson ME, Vierck CJ, Price DD (2003) Diffuse noxious inhibitory controls (DNIC) attenuate temporal summation of second pain in normal males but not in normal females or fibromyalgia patients. Pain 101:167–174. doi:10.1016/s0304- 3959(02)00325-1 Thomson R (1982) Side effects and placebo amplification. Br J Psychiatry 140:64–68. doi:10.1192/bjp.140.1.64 Vase L (2005) Increased placebo analgesia over time in irritable bowel syndrome (IBS) patients is associated with desire and expect- ations but not with endogenous opioid mechanisms. Pain 115:338–347. doi:10.1016/j.pain.2005.03.014 Wager TD, Dagfinn MB, Casey KL (2006) Placebo effects in laser- evoked pain potentials. Brain Behav Immun 20:219–230. doi:10.1016/j.bbi.2006.01.007 Watson A, El-Deredy W, Vogt BA, Jones AKP (2007) Placebo analgesia is not due to compliance or habituation: EEG and behavioural evidence. NeuroReport 18:771–775. doi:10.1097/ WNR.0b013e3280c1e2a8