Zinberg's research shows that psychological and social factors affect drug use outcomes, not just the drug's biochemical properties, but we already know that from placebo/nocebo effects (set) and group dynamics (setting), among other factors. The problem I have is the spirit of the book which is something along the lines of "drug use can be beneficial, you can get the highs without the negative consequences, and you can even play better piano and do your job better".
The purpose of his research was to show that controlled intoxicant use is possible. That's the first bias. It's a study to prove a point. But what worries me is that people can "anchor" their perceived positive feelings (escapism) with opiate use and that's when people can go down the slippery slope. The long term damage through opiate use, even if people can have "controlled use", is not given attention.
In his data analysis (p.76), the number of compulsive subjects using opiates for depression is 80% while for controlled subjects only 21%. It is a quantitative study design starting with a hypothesis and then proving it, which is what quantitative studies do, but then in chapter 4 he uses qualitative methodology but transcribes only the tapes from controlled users and not the compulsive users (in order to prove his point). He does not address the problematic users who end up homeless on the street.
What Zinberg did not focus his attention on (because he sets out to prove controlled use) is that if 80% of compulsive users use it to beat depression, then potentially, advocating "controlled" use might have dire consequences, as evidenced in my work as a counsellor who has worked with many sad cases of drug dependence. Many of these people started out as "controlled" users, until something in their life goes wrong (breakup, death in family, etc) and then they become problematic users who lose their house, their family, their self-esteem, and maybe even very nearly their lives.
The closing paragraph of the book says this:
Throughout the duration of my project my subjects continued to make one point clear: at certain times, if not during the whole of their using careers, they experienced benefits from their intoxicant use and from different patterns of use. Thus despite the reigning cultural morality, future studies of intoxicant use should take into account not only the liabilities but also the benefits of drug use itself and also the differing patterns of use.
The spirit of the book throughout is to show you how SOME people can experience highs and function well from drug use (duh, so what? - we can get high on more wholesome things such as helping the less fortunate and getting a real buzz!) Throughout the book he implicitly condones drug use because of the "benefits".
I would be sold on his idea of controlled use if he could have shown another study with the hypothesis that "opiate use is detrimental to life expectancy, health, family, social, financial, career aspects of life, in the long term" and that study fails the hypothesis.
You can prove whatever you WANT to prove!
I give it a two star because the implicit personal bias throughout the book is ANNOYING. Without that bias, and with the same findings, the concluding paragraph might be more responsible and read something like this instead:
From my research, it appears that some opiate users are able to control their intoxicant use and experience positive effects that are beneficial to their lives, without becoming problematic users. It would seem that the traditional view that all opiate users must progress from experimental to moderate use, then become addicted and finally becoming compulsive users may not be accurate. However, there is a possibility that controlled users can become compulsive users and that there may be long-term negative effects. Further research is needed to explore these possibilities, particularly if emotional stressors present in users' lives. Before such data becomes available, it would be responsible to assume such possibilities as the negative consequences of slipping into compulsive use with long term ill effects, may outweigh the positive experiences of controlled use.