What 20 Years Of Research Has Taught Us About The Chronic Effects Of … – Forbes

Dried marijuana bud.

A new study in the journal Addiction lays out what the vast research on marijuana has revealed over the last 20 years, highlighting the drug’s adverse effects, both acute and chronic. Though researchers have been studying the effects of marijuana for decades, the science has really exploded just in the last 20 years, due in part to better study methods, and also spurred by the growing interest in legalization. The new study maps out exactly what marijuana does and does not do to the body and brain, both in the short and long terms. What’s clear is that marijuana has a number of adverse effects over years of use – in certain people, anyway. What’s not so clear is how policy should be informed by the science. But the researchers suggest that with increasing legalization should come increasing public awareness of the sometimes-serious effects of chronic use.

Acute Effects

The acute effects aren’t so bad: No one has ever died from a natural marijuana overdose, the study found. (N.B. This is not true for synthetic marijuana, which can be very dangerous.) Driving while high on marijuana does seem to double the risk of a car crash, which is of course heightened if there is also alcohol in the system. Marijuana has been linked to low birth weight when it is used during pregnancy. Otherwise, acute effects mainly include anxiety, paranoia (especially among new users), dysphoria, cognitive impairment, and psychotic symptoms (especially in people with a family history of psychosis). These particular side effects seem to have risen over the last 20 years, which may be due to the fact that the THC content in marijuana has also risen over that time.

Dried marijuana bud. (Photo credit: Wikipedia)

Chronic Effects

Over the long term, things get a little worse. It’s important to point out …read more