A new drug can help people diagnosed with cannabis use disorder reduce withdrawal symptoms and marijuana use, a new Yale-led study published Dec. 6 in the journal Lancet Psychiatry shows.

The double-blind, placebo-controlled study shows marijuana use declined among subjects who were administered the new drug—a fatty acid inhibitor that acts upon endocannabinoid metabolic receptors in the brain—compared to those receiving a placebo. Subjects who took the drug also reported fewer withdrawal symptoms and exhibited better sleep patterns, which are disrupted in cannabis-dependent individuals attempting to quit.

“With an increase of marijuana legalization efforts, it is reasonable to expect an increase in demand for treatment, and right now we don’t have any medications to help individuals trying to quit,” said Deepak Cyril D’Souza, professor of psychiatry at Yale and corresponding author of the study.

Cannabis use becomes a disorder when the person cannot stop using the drug even though it interferes with many aspects of his or her life. Cannabis use disorder (CUD) is marked by social and functional impairment, risky use, tolerance, and withdrawal symptoms, according to DSM-5, the statistical manual of mental health disorders developed by the American Psychiatric Association. Withdrawal symptoms are marked by craving for marijuana, irritability, anger, depression, insomnia, and decrease in appetite and weight.

In 2015, about 4 million people in the United States met the diagnostic criteria for a cannabis use disorder, and almost 150,000 voluntarily sought treatment for their cannabis use.

According to recent national data, approximately one-third of all current cannabis users meet diagnostic criteria for CUD.

For the new study, D’Souza and colleagues recruited male daily cannabis users. Seventy subjects completed the trial, with 46 receiving the drug and the remainder receiving placebo. All subjects in the study underwent forced withdrawal on the inpatient research unit for the first week and continued receiving treatment for three weeks as outpatients after release from the hospital.

A reduction in cannabis use was confirmed by both self-report and urine drug testing.

Researchers have tried many different drugs in an attempt to reduce cannabis withdrawal symptoms and increase abstinence in those trying to quit, but none have been consistently successful or well tolerated, D’Souza said.

The new drug works by inhibiting fatty acid amide hydrolase (FAAH), the enzyme that degrades anandamide, a brain chemical that acts on brain cannabis receptors. Anandamide is an endocannabinoid present in the human body that is produced naturally by the brain.

“Anandamide is to cannabis as endorphins are to heroin,” D’Souza said.

A larger multicenter trial of the new drug funded by the US National Institute of Drug Abuse is currently underway.

The research was funded by the National Institute of Drug Abuse.