According to a study in The Lancet, “There is now sufficient evidence to warn young people that using cannabis could increase their risk of developing a psychotic illness later in life.”

First, the details.

• The researchers searched the medical literature through September 2006.
• 35 studies were identified and included in the review.

And the details.

• There was a significant increased risk of a psychotic outcome in people who had ever used cannabis during their lives.
• Those who used cannabis most frequently were at greatest risk.
• Those who smoked pot regularly at age 18 were 1.6 times more likely to suffer serious psychiatric problems, including schizophrenia, by their mid-20s.
• Those who smoked pot regularly at age 15 were 4.5 times more likely to suffer serious psychiatric problems, including schizophrenia, by age 26.
• A relationship between smoking pot and depression, suicidal thoughts, and anxiety were less consistent.

The bottom line?
In an article in the Daily Mail, the researchers advised, “Although individual lifetime risk of chronic psychotic disorders such as schizophrenia, even in people who use cannabis regularly, is likely to be low — less than 3% — cannabis use can be expected to have a substantial effect on psychotic disorders at a population level because exposure to this drug is so common.”

Dr. Stanley Zammit from Cardiff University adds, “We would still advise people to avoid or limit their use of this drug, especially if they start to develop any mental health symptoms, or if they have relatives with psychotic illnesses.”

7/27/07 20:26 JR