Abstract Background Public policies related to drug use have been formulated based on the guidelines given by international organizations that have classified them based on more socio-legal motivations, lacking a scientific basis. Methods To achieve the hierarchy of harm associated with the consumption of psychoactive drugs through a consensus of experts, complemented with the social representations that communities have in this regard. Principles of Multcriteria Decision Analysis (MCDA) were used and through the Delphi method, 15 expert scientists in psychoactive drugs were consulted, who weighted on a scale the construction of consensus on damages related to 15 psychoactive drugs at the individual level and third parties. In addition, focus groups and individual interviews were conducted with social actors to inquire about their perceptions regarding the harm associated with drug use, both in consumers and in others. Finally, Bayesian elicitation was applied to the qualitative information of the substances, where medians and 95% credibility intervals were estimated. Results The consensus showed that smokeable cocaine (basuco), heroin, alcohol and cocaine were, in order, the most harmful substances for individual users, with medians of 40.3; CRI95% (39.3–41.3); 40; CRI95% (38.9–40.9), 39.7; CRI95% (38.9–40.5) and 39; CRI95% (38.4–39.7), respectively, while cocaine, alcohol and basuco were the most harmful to another 43.4; CRI95% (42.8–44), 42.7; CRI95% (42.2–43.3) and 42.7; CRI95% (42.3–43.1), respectively. For their part, the community actors considered alcohol to be the most harmful substance both for the individual who consumes it and for third parties, followed by cocaine and marijuana. Conclusion The disagreement in the management given to drugs by public policies regarding the problem of both legal and illegal drug use is corroborated, in relation to the international discussion the variables that had more weight in the context Colombia were those related to violence, displacement and crime associated with the production and trafficking of substances.