Teenagers who smoke marijuana, drink alcohol or vape before turning 15 have a different brain structure than those who don’t, according to a study.
Indiana University researchers tracked nearly 10,000 adolescents over two years, of whom 35 percent reported using alcohol, marijuana, and/or nicotine before age 15.
All participants also underwent brain scans which revealed that those who had used any of the substances before the age of 15 had a thinner prefrontal cortex (an area of the brain linked to emotion regulation) compared to those who said who had not used drugs or alcohol at a young age. .
Those who reported using substances when they were young also tended to have larger brains overall and greater subcortical volume, the area of the brain linked to memory, emotions, pleasure and hormone production.
The scientists said it was not clear whether the substances altered the teens’ brains or whether teens with certain brain characteristics were predisposed to try substances.
The researchers concluded that different brain structures may reflect a predisposition that adolescents have to use substances earlier in life, which could have “possible cascading implications for the development of later problems.”
Dr. Nora Volkow, director of the National Institutes on Drug Abuse (NIDA), said: “This adds to some emerging evidence that an individual’s brain structure, along with their unique genetics, environmental exposures and “Interactions between these factors can affect your risk level.” and resilience to substance use and addiction.
“Understanding the complex interplay between factors that contribute to and protect against drug use is crucial to informing effective prevention interventions and providing support to those who may be most vulnerable.”
Teenagers who smoke marijuana, drink alcohol or vape before turning 15 have a different brain structure than those who don’t, according to a study (file image)
For the study, published this month in Open JAMA Networkchildren were recruited from the Adolescent Brain and Cognitive Development study (ABCD study).
The study, created by NIDA, aims to analyze children’s brain development and how it can be affected by certain factors, including drug abuse.
For the current article, children were recruited from 22 locations in the US and were nine years old at the beginning of the study.
They were tracked from June 1, 2016 to October 15, 2018 and asked to report whether they had used any substances.
Among the 3,460 respondents who admitted to using substances before turning 15, alcohol was the most used substance: 90 percent reported this.
About 62 percent of participants also reported using nicotine, while 52.4 percent said they had used marijuana before age 15.
In the analysis, adjusted for factors such as gender, the researchers identified five key whole-brain differences between the two groups, including different overall brain size.
These were that adolescents who reported having used substances were more likely to have a thinner prefrontal cortex overall, but a thicker cortex in all other lobes, such as the occipital lobe, the area of the brain linked to visual perception, including color, shape and movement.
The results also showed that they had a larger brain, a larger globus pallidus (a structure that regulates voluntary movements), and a larger hippocampus (an area of the brain that helps with learning and memory).
At the regional level, they also identified 39 differences between the two groups, about 56 percent of which were related to cortical thickness.
Of these, 22 of them (or 56 percent) were related to variations in cortical thickness, with the cortical being the outer layer of the brain and important for higher-level processing, such as language, memory and reasoning.
There were also some differences depending on the substance consumed, as those who used cannabis had a lower right caudate volume, an area linked to the processing of visual information.
The researchers wrote in the study: ‘Our findings suggest that structural differences in the prefrontal cortex may predispositionally contribute to the initial stages of substance involvement.
“Our data cannot yet determine at what point(s) in development variability in substance-related brain structure arose.
“Large-scale longitudinal studies…that track neurodevelopment and substance exposure or involvement from the neonatal period to early adulthood are needed to address the origins of these differences.”
The rate at which adolescents use substances has worried experts about the effects on brain development.
Previous research has shown that teen binge drinking, or binge drinking, slows the growth of areas of the brain related to impulse control, memory and learning and may also leave them at higher risk of depression.
Smoking marijuana at a young age can also affect the way the brain builds connections and thickens gray matter, which could cause lifelong memory, attention, and learning problems.
There have also been suggestions that vaping nicotine could increase the risk of dementia by narrowing the blood vessels that supply the organ.
Researchers of the study published this month hope the data can be used to help identify those at risk of substance addiction early and prompt rapid interventions.