Neurobiologist Yasmin Hurd of the Icahn School of Medicine at Mount Sinai has a beef with the lack of research on how cannabinoids and extracts of cannabis from medical marijuana can reduce cravings and ease withdrawal symptoms of heroin users. She has been studying how both cannabinoids and opioids act on the brain and recently published her position in Trends in Neurosciences.
“If you look at both drugs and where their receptors are, opioids are much more dangerous, in part because of the potential for overdose-the opioid receptors are very abundant in the brainstem area that regulates our respiration, so they shut down the breathing center if opioid doses are high,” Hurd says. “Cannabinoids don’t do that. They have a much wider window of therapeutic benefit without causing an overdose in adults.”
Both cannabinoids and opioids regulate the perception of pain, but they affect different parts of the brain and how the sensation is communicated from neuron to neuron. This translates into cannabinoids having, for example, a stronger effect on inflammation-based chronic pain. Meanwhile, opioids are particularly good at relieving acute pain, which is why they are used in surgery. The problem is that opioids can quickly lead to a deadly addiction.
A specific cannabinoid, cannabidiol, has been seen to reduce heroin cravings in animals more than a week after abstinence, and seems to restore some of the neurobiological damage induced by opioid use. A small pilot human investigation led by Hurd mirrored these findings in rodents. In the study, cannabidiol particularly helped relieve anxiety related to cravings in heroin users abstaining from use.
The National Institute on Drug Abuse is asking researchers to think creatively about new strategies for pain relief. While there has been a growing interest by the scientific community in cannabinoids since the legalization of medical marijuana, but that has not translated into much greater knowledge about how it could be used therapeutically, despite at least a million people having prescriptions.
“We have to be open to marijuana because there are components of the plant that seem to have therapeutic properties, but without empirical-based research or clinical trials, we’re letting anecdotes guide how people vote and policies that are going to be made,” Hurd says. “It’s one of the first times in our history that we’re making laypeople and politicians decide whether things are medicinal or not. If we want to say something is medical marijuana, we have to prove that it is medicinal.”