Cannabis use increases risk of neurocognitive deficits, reduced attention and impulse control, worsening of psychiatric symptoms and precipitation of psychosis.
"Marijuana use is highly prevalent among teenagers in North America and Europe," says study leader Dr. Patricia Conrod. "As attitudes and laws towards marijuana are changing, it is important to find ways to prevent and reduce its use amongst at-risk youth. Our study reveals that targeted, brief interventions by trained teachers can achieve that goal."
Although modern societies are increasingly accepting of cannabis use, studies into the harms of cannabis report increased risk of neurocognitive deficits and motor vehicle accidents, reduced attention and impulse control, worsening of psychiatric symptoms and precipitation of psychosis.
The researchers studied 1,038 ninth-grade British students across 21 high schools in London. These teenagers were identified as being at high risk using a clinically validated personality assessment. Factors that put teenagers at greater risk of substance abuse include anxiety, negative thinking, impulsiveness or sensation seeking.
The students took part in two 90-minute cognitive behavioral therapy (CBT) sessions that were personalized to their specific personality type. In the sessions, real-life scenarios were described to the students by other at-risk teenagers. This strategy was designed to explain how risk can be managed. However, cannabis was not directly mentioned, unless the students brought the subject up themselves.
"There were signs that the program delayed onset and reduced frequency of cannabis use in all youth who participated in the interventions, but the results also consistently showed that the program was particularly effective in preventing cannabis use among those most at risk of using - sensation seekers," says Dr. Conrod.
Intervention associated with delays in initiation of cannabis use over follow-up period
Drug use by the students following the intervention was reported by the participants anonymously completing questionnaires every 6 months over the following 2 years.
Dr. Conrod and colleagues report that about 25% of the high-risk students initiated cannabis use over the course of the 2-year follow-up period. They also claim that the intervention was associated with a 33% reduction in cannabis use within the initial 6 months following the CBT sessions and reduced frequency of use within the subsequent 6 months.
The group at greatest risk for cannabis use were sensation-seeking students, and the intervention was linked with a 75% reduction in cannabis use among this group in the 6 months following the intervention, "as well as significant reductions in frequency of use thereafter."
According to first author Ioan T. Mahu, sensation-seekers require a lot of stimulation, are less inhibited and less tolerant of boredom, and are therefore willing to take greater risks than their peers to find excitement:
"Sensation-seekers are particularly at risk of cannabis use amongst this young age group. It is possible that other personality traits predict cannabis use at older ages. Future studies should look at the motivations for cannabis use amongst people with other at-risk personality types in order to develop intervention programs that are as effective as this one has been for sensation-seekers."
Dr. Conrod concludes that, because of the harms associated with early initiation of marijuana use among teens, "prevention and delay of this behavior is of utmost importance for the public, particularly as society experiments with different public policies to regulate cannabis-related harm to society."
Recently, Medical News Today looked at research that found marijuana use may stunt growth and trigger early puberty in boys.