Increasing evidence of brain harm from marijuana use

Although there are already many known ways in which marijuana harms the well-being and

health of a young adult, new research - funded by the National Institute on Drug Abuse (NIDA) -

has indicated the potential detrimental effects on the brain of the drug's heavy use.

For the purposes of this study, heavy marijuana use is defined as a minimum of four times per

week over the previous six months, a frequency that has been linked to adverse changes in the

function and structure of parts of the brain that deal with reward, decision-making and

motivation.

The enhancement of some brain circuits that can also arise from heavy marijuana use may be

means of compensation for reduced function in certain regions of the brain. This effect was

especially pronounced in those who began using marijuana at a young age, which suggests a

particular susceptibility to marijuana's effects in still-developing brains.

The research was conducted at the Center for Brain Health at The University of Texas at Dallas,

with its findings published in a paper in Proceedings of the National Academy of Sciences (PNAS).

The researchers found that chronic marijuana use effect on the brain may depend on the age of

first use as well as the duration of use.

Multiple magnetic resonance imaging (MRI) techniques were used to provide the first

comprehensive description of existing brain function and structure abnormalities in those who

used marijuana on a long-term basis. Smaller brain volume in the orbitofrontal cortex (OFC) - an

area of the brain frequently linked to addiction - was found in chronic marijuana users, as well as

higher brain connectivity.

Dr. Francesca Filbey, Associate Professor in the School of Behavioral and Brain Sciences at the

University of Texas at Dallas and Director of the Cognitive Neuroscience Research in Addictive

Disorders at the Center for BrainHealth, commented: "We have seen a steady increase in the

incidence of marijuana use since 2007. However, research on its long-term effects remains

scarce despite the changes in legislation surrounding marijuana and the continuing conversation

surrounding this relevant public health topic."

Indeed, additional long-term studies will be required to determine whether marijuana was the

cause of the effects on the brain documented in this most recent research. Nonetheless, such

scientific findings enhance the existing body of literature indicating the potentially harmful effects

of heavy marijuana use on the brain - interesting news for anyone considering the services of a

North Carolina rehabilitation facility.