The effects of caffeine and nicotine consumption on mood and somatic variables in a penitentiary inmate population.

A sample of 144 inmates from a maximum security penitentiary responded to a request for information regarding their average daily intake of nicotine and caffeine. They also rated the quality of their appetite and sleep, their level of concentration, their mood and specific feelings of anger, anxiety, frustration, and irritability. Factor analysis generated a two-factor solution of these variables, namely general mood state (mood, anxiety, anger, frustration, and irritability) and a somatic state (appetite, concentration, and sleep). Analysis of variance showed an interaction between level of smoking (nonsmokers, low and high cigarette smokers) and caffeine use (moderate vs. high) on the general mood factor. Nonsmokers who consumed high levels of caffeine experienced poorer general mood than any other group. There was a main effect of cigarette smoking status on the somatic factor, such that greater dissatisfaction was associated with greater consumption. Caffeine consumption was generally high, averaging 800 mg of caffeine per day, per inmate, well above the amount considered to be potentially damaging to health.