Neurology | Tobacco & Marijuana |

Cannabis Smoking Common, Affects Cognition in MS

May 31, 2015 Viewed: 1784

Adolescents Vulnerable

The life stage at which people in general start smoking cannabis appears to be important for cognition. Dr Feinstein cited a 2012 New Zealand study that followed over 1000 participants for 25 years, checking cannabis use along the way. The researchers found that people who started smoking pot during adolescence and used it fairly regularly (defined as more than four times a week) had significant cognitive deficits by the time they were in their 30s.

“Some of those deficits don’t return,” said Dr Feinstein. “It seems pretty clear that a very vulnerable group are adolescents.”

But if they didn’t pick up the habit during adolescence, persons without MS who quit smoking can return to the same cognitive level they had before. The “big unknown question,” however, is whether cognition goes back to baseline for patients with MS if they stop smoking cannabis, said Dr Feinstein. “We don’t know that yet.”

Dr Feinstein noted that it’s difficult to study the effect of smoking marijuana on cognition. There are multiple confounders, including the duration and frequency of use and the potency of the strain smoked.

Attitudes toward smoking pot have changed drastically in recent years. “I think now that a slight majority would say there’s nothing wrong with smoking cannabis, said Dr Feinstein, who himself acknowledged having “changed his tune over the years” on the topic.

Asked his opinion of patients with MS using cannabis, Michael Racke, MD, professor, neurology, Ohio State University, Columbus, pointed out that it can cause significant lung damage, is still illegal in many places, and can affect day-to-day functioning.

“I can take my injection of interferon and go and drive my car, and it’s no big deal, but if I smoke a joint and drive my car, I might be stopped for driving under the influence.”

Cannabis Smoking Common, Affects Cognition in MS But he agreed that attitudes about smoking cannabis have changed significantly, with several states, Washington and Colorado, for example, having legalized it.