It’s hard to read a newspaper these days without seeing an article about the epidemic of drug use and drug overdoses sweeping the country. Addiction to all kinds of substances remains a major health problem and treatments are often tragically unsuccessful. Recently, however, we’ve begun to better understand the underlying neurological mechanisms of addiction, and with that understanding has come a novel intervention aimed at treating the problem at its source.
There are, in fact, a number of disorders—among them compulsive drug use, gambling, smoking, and eating—that share a common underlying trait: impaired impulse control. Recently, we’ve gained insight into what systems in the brain contribute to compulsively addictive behaviors.
We used to think dopamine was the neurotransmitter of pleasure, or “liking,” but we now know that idea was incorrect. Dopamine is, instead, the neurotransmitter of desire, or “wanting.” When drug addicts see a cue in their environment that reminds them of their drug of choice, the levels of dopamine in the “wanting” systems in their brains rise to extraordinary levels and correlate with the degree of compulsion such people feel to use drugs. This dopaminergic hypersensitivity to environmental cues is driven by derangements in the glutamate system.
N-acetyl cysteine is a drug that’s been used for decades to treat Tylenol overdoses. It’s quite safe and turns out also to normalizes glutamate transmission in the brain, which in turn normalizes the dopaminergic response to environmental cues that trigger drug use. In a recent study, patients with both PTSD and substance abuse disorder were given n-acetyl cysteine to see if it would reduce their cravings for drugs and decrease their symptoms of PTSD (which also seem at least partially attributable to derangements in the glutamate system of the brain). Thirty-five veterans were given 1,200 mg of n-acetyl cysteine twice daily for 8 weeks. In comparison to a placebo group, subjects who received n-acetyl cysteine had a 32% reduction in the their PTSD symptoms (compared to 8% in the placebo group) and an 81% reduction in the total amount of cravings for drugs (compared to 32% in the placebo group) as measured on standardized scales. The frequency of their cravings for drugs also decreased by 72% (compared to 29% in the placebo group). The intensity of cravings, interestingly, weren’t different between the treatment and placebo groups. Finally, depressive symptoms declined in the treatment group by 48% (compared to 15% in the placebo group). Dry mouth and heartburn were the most frequently reported adverse drug events.
While a small study, it was randomized, blinded, and placebo-controlled and showed clinically and statistically significant reductions in PTSD symptoms, drug cravings, and even depressive symptoms. This study clearly demonstrates that drug addiction is a neurological disease—a neurological derangement of the brain’s “wanting” system—that’s amenable to correction, and further that when it’s corrected there is a significant return to normalcy.
Whether treatment with n-acetyl cysteine will be effective for other disorders of “wanting” such as food, gambling, tobacco, and sex addiction remains to be seen. However, the notion that these problems come from a neurologic derangement and not just from weak willpower and that we might be able to correct the derangement is surely one of the most exciting findings to come out of research in a long time.