New treatments for depression and experiments which might help explain human consciousness will be put at risk if the bill banning legal highs is passed, researchers have warned.
In an open letter to Theresa May, leading British scientists urged the home secretary to add an exemption for "research pharmaceuticals being used to develop new medicines or progress neuroscience research", so that new treatments and experiments were not brought to a halt by the bill.
"Many types of important research could potentially be affected by the bill, particularly in the field of neuroscience, where substances with psychoactive properties are important tools in helping scientists to understand a variety of phenomena, including consciousness, memory, addiction and mental illness," the letter reads.
"The bill, as currently worded, could be interpreted to include experimental substances like these, putting such research at significant risk."
The scientists raised the hypothetical example of a researcher who produced a compound with mild psychoactive effects in order to explore a particular pathway associated with depression. Even with approval from the Research Ethics Committee, that researcher would be liable for prosecution if they set up a small study of the substance using volunteers.
The psychoactive substances bill already has an exemption for investigational medicinal product, but this does not apply to purely experimental substances which are not expected to have a therapeutic effect.
"We consider it essential that the current draft bill be amended to better safeguard basic medical research, both within neuroscience and other fields," the authors write.
"We encourage the Home Office to take the risk to medical research into consideration as the bill progresses, and to seek to ensure that the final draft does not pose a barrier to important scientific work, both in neuroscience and in other areas."
The letter was signed by the president of the Academy of Medical Sciences, the president of the British Pharmacological Society, the president of the Royal College of
Psychiatrists, the biological secretary of the Royal Society, the president of the Society of Biology and the head of policy at the Wellcome Trust.