* Need more information? See our latest book: The Mind: A User's Guide
* Related leaflets: Alcohol; Our Favourite Drug, Alcohol and Depression
About this leafletTwo million people in the UK smoke cannabis. Half of all 16 to 29 year olds have tried it at least once. In spite of government warnings about health risks, many people see it as a harmless substancethat helps you to relax and ‘chill’ – a drug that, unlike alcohol and cigarettes, might even be good for your physical and mental health. On the other hand, recent research has suggested that it canbe a major cause of psychotic illnesses in those who are genetically vulnerable.
This leaflet looks at the research on the effects of cannabis use and mental health and is for anyone who is concernedabout the issue. We hope that this will help people to make informed choices about using – or not using – cannabis.
What is cannabis?
Cannabis sativa and cannabis indica are members of the nettlefamily that have grown wild throughout the world for centuries. Both plants have been used for a variety of purposes including hemp to make rope and textiles, as a medical herb and as the popularrecreational drug.
The plant is used as:
* The resin – a brown/black lump, known as bhang, ganja, hashish, resin etc;
* Herbal cannabis – made up of the dried flowering tops and variable amountsof dried leaves - known as grass, marijuana, spliff, weed etc.
Skunk refers to a range of stronger types of cannabis, grown for their higher concentration of active substances. The name refers to thepungent smell they give off while growing. They can be grown either under grow-lights or in a greenhouse, often using hydroponic (growing in nutrient rich liquids rather than soil) techniques. Thereare hundreds of other varieties of cannabis with exotic names such as AK-47 or Destroyer.
Street cannabis can come in a wide variety of strengths, so it is often not possible to judge exactly...