By Nicole MacKee
Almost half of people who use cannabis regularly will experience a cluster of withdrawal symptoms, including disturbed sleep and anxiety, when they reduce cannabis use, researchers have reported in JAMA Network Open.
A systematic review and meta-analysis of almost 50 studies, representing 23,518 participants, found that 47% experienced cannabis withdrawal syndrome when they cut down their cannabis use. The diagnosis, which was included in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition in 2013, requires at least three of the following symptoms to develop within a week of reducing cannabis use: irritability, anger or aggression; nervousness or anxiety; sleep disturbance; appetite or weight disturbance; restlessness; depressed mood; and somatic symptoms, such as headache or nausea.
Professor Nicholas Lintzeris, Conjoint Professor in Addiction Medicine at the University of Sydney, said awareness of cannabis withdrawal syndrome among doctors and people who used cannabis remained low in Australia.
‘Only a decade ago, there wasn’t even a diagnosis for cannabis withdrawal,’ he said. ‘Many doctors would not have been trained about the existence of cannabis dependence or there being withdrawal symptoms. [The symptoms] also take a lot of people who use cannabis regularly by surprise when they try to stop.’
Professor Wayne Hall, Professor at the University of Queensland’s Centre for Youth Substance Abuse Research, said there was a perception among people who used cannabis that cannabis was not a drug of dependence.
He also noted that, unlike withdrawal from alcohol or opiates, the symptoms arising from cannabis withdrawal were likely to be delayed in onset.
‘It’s a drug that hangs around in the system for quite a while. And the [withdrawal] symptoms are quite nonspecific, typically difficulty sleeping, a bit of irritability, anxiety and restlessness,’ he said. ‘These symptoms can be a major barrier to people stopping because the easiest way to get rid of them is to smoke another joint.’
Professor Hall said greater awareness of cannabis withdrawal syndrome would help those seeking to reduce their cannabis use.
‘It’s something that [people who use cannabis] need to address and expect, and to know that it is time limited,’ he said. ‘If they are planning to stop cannabis use and stay stopped, they may need to get through this period.’
Professor Lintzeris was the lead researcher of a randomised controlled trial, published last year, that found that a three-month course of the cannabinoid agonist medication nabiximols, coupled with counselling, could reduce cannabis use and dependence (JAMA Intern Med 2019; 179: 1242-1253). The medication was not currently indicated for this use in Australia and cost remained a barrier to this treatment, Professor Lintzeris said.
JAMA Network Open 2020; 3: e202370; doi:10.1001/jamanetworkopen.2020.2370.