Cannabis Breakthrough: Scientists Separate Drug’s Medicinal Benefits From its Hallucinogenic Effects
- Scientists discovered inhibiting a receptor in the brain meant they could trigger cannabis’ medicinal benefits but not its unwanted side effects
- Drug is thought to help slow tumour growth in cancer patients and can also help with nausea, anxiety and pain relief, some studies suggest
- Hope breakthrough will pave the way for safe cannabis-based therapies that do not cause alterations in mood, perception or memory.
Scientists have, for the first time, been able to separate the medical benefits of cannabis from its unwanted side effects, it has emerged.
The research comes from the team that discovered how the main psychoactive ingredient in cannabis, known as THC, reduces tumour growth in cancer patients.
Their latest findings reveal how the cognitive effects of THC, such as memory loss and anxiety, are triggered by a pathway which is separate from some of its other effects, including pain relief.
That pathway involves both a cannabinoid receptor and a serotonin receptor.
Scientists have managed to separate the medical benefits of cannabis from its hallucinogenic effects
When it is blocked, THC can still exert several beneficial effects while avoiding impairment of memory.
The research was carried out in mice by scientists at the University of East Anglia (UEA) in collaboration with a team at the University Pompeu Fabra in Barcelona.
It is hoped the breakthrough will pave the way for safe cannabis-based therapies that do not cause alterations in mood, perception or memory.
Dr Peter McCormick, of UEA’s school of Pharmacy, said: ‘THC, the major active component of marijuana, has broad medical use – including for pain relief, nausea and anxiety.
‘Our previous research has also found that it could reduce tumour size in cancer patients.
‘However it is also known to induce numerous undesirable side effects such as memory impairment, anxiety and dependence.
‘There has been a great deal of medical interest in understanding the molecular mechanisms at work in THC, so that the beneficial effects can be harnessed without the side-effects.
‘THC acts through a family of cell receptors called cannabinoid receptors.
‘Our previous research revealed which of these receptors are responsible for the anti-tumour effects of THC.
‘This new research demonstrates how some of the drug’s beneficial effects can be separated from its unwanted side effects.’
The researchers carried out behavioural studies in mice and investigated how pathways in their brains operate under THC.
Scientists hope the breakthrough will pave the way for cannabis-based therapies which do not alter mood, perception or memory. But they warn people not to ‘self-medicate’ in the meantime
They found that the absence of a particular serotonin receptor (5HT2AR) reduced some of the effects of THC – such as ability to cause memory loss, based on a standard memory test.
But treatment to reduce 5HT2AR did not change other effects of THC, including pain relief.
Dr McCormick said: ‘This research is important because it identifies a way to reduce some of what, in medical treatment, are usually thought of as THC’s unwanted side effects, while maintaining several important benefits including pain reduction.’
But he warned that patients should not be tempted to self-medicate, adding: ‘Patients should not use cannabis to self-medicate, but I hope that our research will lead to a safe synthetic equivalent being available in the future.’
The findings were published in the journal PLOS Biology.