Even short periods of caffeine deprivation, equivalent to skipping a regular morning coffee, can produce deficit In sustained attention.82 Withdrawal symptoms are rapidly relieved by caffeine Intake. Signs and symptoms of withdrawal, In decreasing order of frequency, Include headache, drowsiness, Impaired concentration, work difficulty, depression, anxiety, irritability, nausea or vomiting, and muscle aches and stiffness.83 The withdrawal syndrome usually shows an onset 18 to Inhibitors,research,lifescience,medical 24 h after cessation; Its Intensity peaks between 20 to 48 h after abstinence; its duration ranges from 2 days to a week. Tolerance to the sleep-disturbing effects of caffeine has been demonstrated. However, there Is little

evidence for upward dose adjustment, possibly because of the unpleasant

Inhibitors,research,lifescience,medical effects of higher doses. Since caffeine is not associated with significant health hazards or Incapacitation, Its potential to Induce dependence does not pose a serious problem for the Individual or society. Overlapping addictions No psychoactive drug has been studied In so many individuals as have alcohol, nicotine, and caffeine. The experience that we have with these Inhibitors,research,lifescience,medical compounds Is tantamount to an open trial conducted over a couple of millennia In billions of subjects! This review of mankind’s most consumed drugs could also have encompassed betel and khat, which are both widely consumed In Africa and Asia for their mild stimulant properties. In the near future, we are likely to gain more experience with cannabis, the use of which Inhibitors,research,lifescience,medical Is

tending to be signaling pathway decriminalized. Since these drugs are so much appreciated, It may be assumed that they procure beneficial and pleasant effects. The benefits obtained in terms of creativity, anxiety reduction, social disinhibition, and pleasure have been extensively described In poetry and literature, rather that In medical treatises. There exists a tendency for some normally functioning adults to have multiple addictions. This led many authors to discuss theories of addictive personality. A study84 of overlapping addictions to common substances (alcohol, caffeine, chocolate, or cigarettes) and activities (exercise, gambling, Internet use, Inhibitors,research,lifescience,medical television, or video games) In college men and women found moderate to large correlations, Bumetanide both within and between substances and activities. Several gender differences In addictive tendencies were also revealed: men scored higher than women on addiction to alcohol, cigarettes, gambling, television, and Internet use, but women scored higher on caffeine and chocolate. Animal studies have shown that rewards obtained from various drugs, as well as food, playing, and sex, stimulate a midbrain reward circuit, involving dopamine and structures such as the nucleus accumbens. The Issue of addiction Is more complex In humans, who have the conscious capacity to evaluate, In the prefrontal cortex, whether pleasurable activities are appropriate and acted upon, or should be deferred or resisted.