Does Marijuana Really Kill Brain Cells?

September 13, 2009

“Smoking marijuana kills brain cells.” If you have ever smoked marijuana you’ve probably heard this myth at some point or another. But you might not know the horrible origins of this dreadful lie.

It was Ronald Reagan who said “the most reliable scientific sources say permanent brain damage is one of the inevitable results of the use of marijuana.” What were those reliable scientific sources you ask?

In 1974, Dr. Robert G. Heath, a researcher at Tulane University in New Orleans, reported that he had found proof that marijuana caused brain damage while experimenting on monkeys. Heath reported that rhesus monkeys smoking an equivalent of 30 joints a day began to atrophy and die after just 90 days. Autopsies revealed that the monkeys who had been exposed to the marijuana smoke had more dead brain cells than the control monkeys, who had not been exposed.

How did Heath come up with these results? What were his procedures? For six years, no one knew. It took Playboy and NORML six years of requesting and suing under the Freedom of Information Act to finally receive an accurate accounting of the procedures Heath used.

Four monkeys were strapped into chairs with transparent plastic boxes surrounding their heads. The head chamber was sealed so that the smoke being pumped in wouldn’t be lost. This also meant that the carbon monoxide couldn’t escape either. Instead of the 30-joints-a-day dosage that Heath had reported, the monkeys were given the equivalent of 63 joints in five minutes, every day, for three months.

The poor monkeys were being suffocated for five minutes at a time, on a daily basis, over a period of three months. After which they were killed so that their brains could be autopsied, and the dead brain cells caused by carbon monoxide poisoning were attributed to marijuana. This was Ronald Reagan’s “reliable scientific” source.

Heath’s experiments have since been criticized for insufficient sample size and failure to control other determining factors, such as the carbon monoxide poisoning. Similar experiments, involving more monkeys and better control, have since contradicted Heath’s reported findings. But sadly, the lie based on his research is still used to frighten smokers today. And will most likely continue to be used until enough people know the truth.

It is not always wise to believe everything you read, so do the research yourself. Marijuana doesn’t kill brain cells; lack of oxygen does, so everyone remember to breathe.

- By Brian Breeding