Chronic marijuana use may alter brain structure, study finds

Heidi from Limburg, Belgium, smokes a joint in the Toermalijn coffee shop in Tilburg April 29, 2012. A controversial law that will make it harder for foreign tourists to buy cannabis at the Netherlands' famous coffee shops has been upheld by a Dutch court. The law, which goes into force in three southern provinces on May 1 before going nationwide next year, means coffee shops can only sell cannabis to registered members. Picture taken April 29, 2012. REUTERS/Michael Kooren (NETHERLANDS - Tags: SOCIETY BUSINESS DRUGS TRAVEL) - RTR31G54 (REUTERS/Michael Kooren)

Heavy marijuana users may have abnormal brain structures which can lead to poor memory, Nature World News reported.

In a new study, researchers from Northwestern Medicine used magnetic resonance imaging (MRI) to analyze the brains of 67 former marijuana users.  The participants had begun their drug use when they were 16 to 17 years old, but they had all been marijuana free for an average of two years at the time of the study.

The imaging scans revealed that participants’ chronic marijuana use was associated with poor growth in the brain’s deep subcortical gray matter – a region linked with memories.  The researchers also found that the brain structures of the marijuana users closely resembled the brains of schizophrenia patients.

"The study links the chronic use of marijuana to these concerning brain abnormalities that appear to last for at least a few years after people stop using it," said lead study author Matthew Smith, an assistant research professor in psychiatry and behavioral sciences at Northwestern University  Feinberg School of Medicine. "With the movement to decriminalize marijuana, we need more research to understand its effect on the brain."

Click for more from Nature World News.