Bravo to Müller & Schumann (M&S) for their gutsy rethinking of drug use as a normal part of human behavior. Their notion of drug instrumentalization suggests that drug use is a major way that people try to overcome the mismatch between evolved human nature and the peculiar demands of modern society. In this view, our ancestors for millennia had been evolving endogenous psychoactive chemicals such as hormones and neurotransmitters to cope with the behavioral demands of prehistoric life. With the rise of agriculture, cities, divisions of labor, and legal monogamy, human life became more complex and frustrating faster than genetic evolution could track, so people turned to exogenous drugs to cope with civilization's loneliness, monotony, oppression, anxiety, and chronic stress. Eventually, far-future humanoids may genetically engineer their brains to include drug-glands that secrete a much wider array of useful psychoactives on demand, as depicted in the science-fiction “Culture” novels by Iain M. Banks (Reference Banks2010). Until that future utopia, we do the best we can with the few good drugs available at the moment and the flagrantly irrational drug policies that constrain their use.

So far, three approaches have dominated the drug policy debates:

1. 1. Criminal justice model: punitive prohibition, the drug user as criminal, harm elimination, abstinence as the goal, the War on Drugs, zero tolerance, 12-step programs, moral panic (see Reuter Reference Reuter2009);

2. 2. Public health model: decriminalization, the drug user as patient, harm reduction (Sullivan & Wu Reference Sullivan and Wu2007; Tammi & Hurme Reference Tammi and Hurme2007), moderation as the goal, cost/benefit analysis, the Vienna Declaration for evidence-based drug policy (Wood et al. Reference Wood, Werb, Kazatchkine, Kerr, Hankins, Gorna, Nutt, Des Jarlais, Barré-Sinoussi and Montaner2010);

3. 3. Libertarian model: legalization, the drug user as normal citizen, benefit maximization (Tupper Reference Tupper2008), happiness as the goal, and – to reduce any negative externalities of drug use – a combination of light regulation (Pudney Reference Pudney2010), optimal “sin taxes” (O'Donoghue & Rabin Reference O'Donoghue and Rabin2006), and libertarian paternalism (Sunstein & Thaler Reference Sunstein and Thaler2003) to promote responsible social norms for drug use.

M&S sympathize with both the public health and the libertarian models. By highlighting the benefits of drugs as used by most people most of the time, they imply that drug policy should try to maximize the benefit/cost ratio of drug use in society. Whereas the criminal justice aimed to eliminate the harm caused by the small proportion of people who use some drugs too much, a benefit-maximization paradigm suggests that most people have not tried enough drugs, do not use enough drugs, and do not manage their drug use as optimally as they might. That is, we are generally underdrugged and misdrugged, not overdrugged.

Many of us are not happy that the three most boring drugs in history – alcohol, nicotine, and caffeine – are the only ones legally available in most of the developed world. M&S offer good reasons that legalizing a much more varied drug-menu could promote not just individual happiness (see Moore Reference Moore2008; O'Malley & Valverde Reference O'Malley and Valverde2004), but also social capital from drug-induced friendliness and neighborliness. For example, group happiness from collective ecstatic rituals (Haidt et al. Reference Haidt, Seder and Kesebir2008) may be promoted by empathogens such as Ecstasy or GHB (Bedi et al. Reference Bedi, Hyman and de Wit2010; Dumont et al. Reference Dumont, Sweep, van der Steen, Hermsen, Donders, Touw, van Gerven, Buitelaar and Verkes2009). Likewise, educational achievement and economic growth might be promoted by legalizing not just caffeine and nicotine, but a wider array of smart drugs such as Ritalin and Provigil (Husain & Mehta Reference Husain and Mehta2011; Repantis et al. Reference Repantis, Schlattmann, Laisney and Heuser2010; Sahakian & Morein-Zamir Reference Sahakian and Morein-Zamir2007). If the social and economic benefits of drug use are real, then nations that legalize more good drugs should attract more investment and skilled workers and should produce more knowledge, wealth, and influence, driving a virtuous cycle of cross-national competition to liberalize drug policies.

Psychoactive drugs may play special roles in the lives of behavioral scientists in generating hypotheses, conducting thought experiments, collaborating sympathetically, and empathizing across ages, sexes, personality traits, mental illnesses, and species. Rumors suggest that some of the best ideas in evolutionary biology and evolutionary psychology since the 1960s were inspired by drug experiences, but researchers rarely credit particular drugs in the acknowledgments sections of their papers. It seems absurd that many psychologists try to understand perception and consciousness without having any personal experience of hallucinogens (Nichols Reference Nichols2004) such as LSD, salvia (Gonzalez et al. Reference Gonzalez, Riba, Bousco, Gomez-Jarabo and Barbanoj2006), psilocybin (Griffiths et al. Reference Griffiths, Richards, McCann and Jesse2006), or ayahuasca (Kjellgren et al. Reference Kjellgren, Eriksson and Norlander2009). Timothy Leary rightly understood that psychology could learn some important lessons from hallucinogens (Leary Reference Leary1967; Leary et al. Reference Leary, Litwin and Metzner1963). I do not expect APA accreditation programs to start requiring LSD trips and Ecstasy raves as part of the doctorate psychology curricula any time soon – but it is worth contemplating how such experiences might instill useful insights, epistemic humility, and clinical empathy in young researchers. In any case, tenured researchers could show more guts by coming out of the closet more often about the role of drug experiences in our scientific lives.

A rational drug policy could include the following elements. Citizens have a basic human right to use psychoactive drugs (as argued by the Center for Cognitive Liberty and Ethics) – except when such use imposes a clear and present danger on others, as when driving or being pregnant. Every drug should be legal for adults unless its benefit/cost ratio is demonstrably close to zero. Learning how to use drugs effectively and safely should be an important part of education from adolescence onward, with opportunities for exploring their various subjective effects, domain-specific benefits, and potential risks. Research should prioritize the discovery of new psychoactive drugs that yield new benefits or reduced side effects. Most urgent, scientists positioned to influence research funding – such as those on NIDA panels – should favor grant proposals that study the benefits, and not just the costs, of psychoactive drugs. Given the heartbreaking mismatch between evolved human nature and the demands of modern society, we need all the help we can get from psychoactive drugs that allow us to learn, work, socialize, mate, parent, enjoy life, and study human consciousness more effectively.