Dependence, addiction and overdose risk

Dependence and addiction

Cannabis can be physically and psychologically addictive. Someone is said to be dependent on cannabis when they experience three or more of these six criteria over a year:

• needing more and more cannabis to get the same high (tolerance)
• experiencing symptoms of withdrawal when attempting to stop using cannabis such as restlessness, irritability, sleep disturbance, loss of appetite, nervousness, anxiety, sweating, and upset stomach.  (withdrawal)
• using more cannabis than was intended
• not being able to stop or cut down cannabis use
• increasing the amounts of time spent getting, using, and recovering from cannabis use
• choosing cannabis use over other important activities
• continuing to use cannabis despite knowing it is causing problems.

Overdose

It is very unlikely a person could overdose on cannabis, and there have been no reported fatalities directly attributed to it. A lethal dose of cannabis is estimated to be 40,000 times the amount needed to intoxicate a person. In comparison, the lethal dose of alcohol is between just 4 and 10 times the dose required to intoxicate.

Some people can have a bad reaction to cannabis use. Often referred to as ‘greening out’, the person might appear pale and sweaty, feel dizzy, nauseous, and may start vomiting.  See our Reducing the harm section for tips on how to deal with ‘greening-out’.