The purpose of this experiment was to develop a valid control group in order to evaluate the effects of caffeine use on learning and memory as well as determine whether cognitive enhancing benefits can be obtained without the potential for adverse psychotropic effects such as anxiety. Previous studies of caffeine’s effects in humans have used overnight abstinence as a control group without actually determining whether the participants were caffeine free. In the current study, 18 participants (14 female, 4 male) were instructed to remain caffeine free for five days prior to treatment and memory testing. Saliva samples were collected each day to confirm caffeine abstinence. Salivary caffeine concentrations were detected during the first 24 hours but changed significantly from day zero (baseline) of the experiment to day five (memory test day). Caffeine administration after five days of abstinence significantly reduced participant pulses (45 minutes after treatment) without affecting learning, retention, caffeine intoxication or withdrawal. These data demonstrate that when participants undergo overnight abstinence they are not caffeine free and cannot be used as a valid control group. This finding calls into question the validity of virtually all of the previous research on caffeine’s effects in humans. These data also demonstrate that when a true control group is used caffeine does not produce a significant change in verbal learning and memory.
Research Report, Final Report Form