Research on Impact of Marijuana on Brain in Binge Drinkers
Researchers have studied extensively the abnormalities in the brain caused by alcohol dependence in adults who have experienced an impairment of executive functioning, memory problems and attention deficits (Chanraud et al., 2007; Pfeerbaum et al., 2000).
Further research is needed to look at the same abnormalities among adolescent drinkers, and specifically at adolescent binge drinkers and the effect marijuana has when used in conjunction. A recent study examined white matter abnormalities in the brains of adolescents who showed a history of sub-clinical binge drinking and binge drinking + marijuana use (Jacobus et al., 2009).
Researchers observed data from the Customary Drinking & Drug Use Record obtained from 42 youths who were evenly distributed into three groups: control group, binge drinkers, or binge drinkers + marijuana users. Binge drinkers were established as having at least one episode of at least four drinks for females and at least five drinks for males.
The group for binge drinkers + marijuana users was designated as those who were categorized as binge drinkers but also had used marijuana between 180 and 1800 times in their lifetime. The binge drinkers + marijuana had significantly more drinking events than did those in the binge drinking only group.
Researchers used diffusion tensor imaging to study participants’ brains and determine the integrity of the white matter fiber clusters as measured by fractional anisotropy (FA) and mean diffusivity (MD). Lower FA numbers and higher MD numbers correlate positively with abnormal white matter structures in the brain.
The researchers found that binge drinkers and binge drinkers + marijuana had significantly lower FAs than the control group. While binge drinkers had significantly lower FAs than controls in all eight fiber clusters examined, binge drinkers + marijuana users had significantly lower FAs in three of the eight clusters examined. Also, binge drinkers had lower FAs than binge drinkers + marijuana users in four of the eight fiber clusters. No significant differences in MD were found between the control group and the binge drinking groups.