DRUG USE CAUSES LONG TERM OR PERMANENT CHANGES IN NEURAL PATHWAYS
AN EX-SMOKER'S GREATEST enemy may not be the cigarette, but the ashtray. Items like needles or clinking glasses might trigger old drug or alcohol cravings after years of abstinence. In a study published in the Journal of Neuroscience, Kent C. Berridge, Ph.D., and Cindy L. Wyvell, Ph.D., professors of psychology at the University of Michigan, found that rats conditioned to associate sugar pellets with amphetamines exhibited cravings for the drugs when exposed to sugar pellets--long after the amphetamines were out of their system. This leads to speculation that drug use causes long-term or permanent changes to certain neural systems.
In the study, rats were trained to seek nonaddictive sugar pellets by pressing a lever and to associate a tonal sound with the pellets. A group of rats were then given amphetamine injections, and the experiment resumed 14 days later, when this group was drug-free. When the rats pressed the lever in search of the sugar reward, they received the sound cue intermittently. The amphetamine-sensitized rats pressed the lever 200 times more than did the control group, at a rate similar to that of rats with amphetamines in their system. Thus, rats on amphetamines and those sensitized but drug-free reacted equally voraciously to the cue.