Polydrug use is using more than one drug at the same time. People use drugs in combination to either increase their intoxication, or to increase the effect of the first drug taken.
Sometimes people mix two drugs because they are already intoxicated and are no longer making rational decisions about their drug-taking and the wellbeing of themselves and those around them. The more drugs being used at the same time, the more likely it becomes that things will go wrong.
Not counting tobacco, the most common form of polydrug use is alcohol and cannabis. When people mix cannabis and alcohol together at one time, the results can be unpredictable. The effects of either drug may be more powerful, or the combination may produce different and unpredictable reactions.
When people smoke cannabis and drink alcohol at the same time they can experience nausea and/or vomiting, or they can react with panic, anxiety or paranoia. Mixing cannabis with alcohol can increase the risk of vulnerable people experiencing psychotic symptoms.
There is some evidence to support that having alcohol in your blood causes a faster absorption of THC (the active ingredient in cannabis that causes intoxication). This can lead to the cannabis having a much stronger effect than it would normally have and can result in ‘greening out’.
Greening out is a term commonly referred to in a situation where people feel sick after smoking cannabis. They can go pale and sweaty, feel dizzy, nauseous and may even start vomiting. They usually feel they have to lie down straight away.
It appears that this is more likely to happen if a person has been drinking alcohol before smoking cannabis rather than the other way around.