New study endorses medication’s efficacy. In a complex design in which it was compared with behavioral treatment/counseling and acamprosate, another medication marketed for relapse prevention in alcoholism, the opiate blocker Revia (naltrexone) gets the nod as helpful. I use this medication for this purpose but have always puzzled about various aspects of how it works if it does.

First of all, as an endogenous opiate blocker, it supposedly blocks some of the activity of the internal reward system and thus diminishes the satisfaction connected with alcohol abuse. But why does it not block most satisfaction in the person’s life if that is the case? There is nothing specific about the effects of alcohol on the endogenous reward system; it responds generically to rewards.

Secondly, addictive behaviors pretty quickly pass beyond the stage of being rewarding; most people persist in abusing addictive drugs because they would be sick or in distress if they stopped. How would a reward blocker matter in such a case? I know I am speaking pretty schematically here, but I need to have some conviction I understand how a medication is supposed to work on a neurochemical basis before I will recommend it to my patients. That is partly because I believe that any medication works less well, or not at all, if the user does not have a belief in its effectiveness. In psychiatric treatment, where most classes of medications were discovered serendipitously and explanations derived after the fact, that is a particular problem.

The effects of naltrexone are modest at best; several studies have found that, while as in this study it was better than acamprosate, the combination of the two is far better than either alone in reducing the frequency and severity of alcoholic relapses. And the benefits usually are more robust in more severe alcoholism.