DOI : 10.1038/nrn3530

Abstract

Many psychoactive drugs are used recreationally, particularly by young people. This use and its perceived dangers have led to many different classes of drugs being banned under national laws and international conventions. Indeed, the possession of cannabis, 3,4‑methylenedioxy- N‑methyl-amphetamine (MDMA; also known as ecstasy) and psychedelics is stringently regulated. An important and unfortunate outcome of the controls placed on these and other psychoactive drugs is that they make research into their mechanisms of action and potential therapeutic uses — for example, in depression and post-traumatic stress disorder — difficult and in many cases almost impossible.

A large number of different classes of psychoactive drugs are controlled (‘banned’) under national laws and international conventions. These controls are supposedly designed to reduce the use of the drugs because of the harms they cause, even though in many cases these harms may be greatly overstated (see below) and may be less than those of some prescription drugs or even legal drugs such as alcohol1,2. Importantly, the harms that derive from the controls themselves may exceed the harms of the drugs, especially when one considers societal harms. For example, the legal consequences of arrest for drug possession are extreme. In the United States, in 2011, 660,000 people were arrested for possession of cannabis (marijuana) and over 50,000 are in prison on cannabis possession charges3. In the United Kingdom, about 1 million people have been convicted for cannabis possession (numbers for people imprisoned are not available). Such penalties limit careers and can destroy livelihoods and families,
raising the question of whether any harmful effect of marijuana justifies a draconian penalty such as imprisonment — sometimes for life.

A small number of psychoactive drugs, including opiates and some stimulants (amphetamines), are allowed to be used as treatments for medical conditions such as pain and attention-deficit disorders, respectively. Others, such as cannabis, 3,4‑methylenedioxy- N‑methylamphetamine (MDMA;
also known as ecstasy) and psychedelics, are controlled more stringently and are therefore not available for therapeutic use. This distinction is not based on the relative harms of these drugs; it is simply a historical accident — older drugs had medical uses before the era of the international conventions and the subsequent ‘War on Drugs’, which allowed them to escape the most stringent controls, as described below.

In this Perspective, we discuss the current state of affairs regarding research using controlled substances and show how the legal approach to drug control has hindered research into the therapeutic potential of
cannabis, stimulants and psychedelic drugs. We argue that the approach of putting penalization of illegal drug possession at the fore of regulatory approaches has severely limited — and continues to limit — neuroscience research and the discovery of new treatments for brain disorders.

The current legal situations

In most countries, the legal control of psychoactive drugs stems from three United Nations treaties: the 1961 Single Convention on Narcotic Drugs4, the 1971 Convention on Psychotropic Substances5 and the 1988 Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances6. The 1971 convention makes it clear that use of Schedule I substances, such as MDMA, psilocybin and lysergic acid diethylamide (LSD; also known as lysergide), is to be severely restricted. Parties to this convention
are to “prohibit all use except for scientific and very limited medical purposes by duly authorized persons, in medical or scientific establishments which are directly under the control of their Governments or specifically approved by them” (REF. 5). This means that research using these substances can be undertaken only after approval of a government agency. In the United States,
this agency is the Drug Enforcement Administration (DEA), whose mission it is, in part, to prevent the diversion of controlled substances. In the United Kingdom, control is exercised by the Home Office,
which can provide sites such as laboratories and hospitals with licences to produce or hold these drugs. Production or use of controlled drugs without such a licence is illegal and can bring severe penalties of up to life imprisonment.

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