The teenage brain it turns out is a brain still undergoing construction. To understand the risks associated with psychoactive substances in adolescents it helps to understand that teenagers are not just less experienced than adults they are undergoing an important yet challenging developmental stage in which that are prone to errors of judgment and sensitive to neurological assault by psychoactive substances. More than any other age group adolescents are at risk for substance addiction and more than any other age group they risk permanent intellectual and emotional damage due to the effects of drugs. The brain is sculpted by experience at birth, the brain contains many more neural connections than it could possible use but these connections are unspecialized and undeveloped. As time passes some connections are strengthened and others are pruned away.The process of refinement and pruning continues throughout childhood adolescence and even into early childhood. The most marked development in adolescence is in the brains frontal lobe and outer mantle.
The pre-frontal cortex executes such skills as setting priorities formulating strategies, allocating attention and controlling impulses the outer mantle is involved with processing abstract information and understanding rules laws and codes of social interaction. The behaviors that accompany these changes are transparent. Teenagers are notorious for their obsession with social interaction for making up social rules and breaking them as teenagers grow into young adults they often exhibit a fascination with abstract thinking on topics like culture and media which demonstrates their growing ability to understand the larger world. Whole the teenage brain is in some ways ill equipped to make decisions and choices without the help of trusted adults it is perfectly designed for the types of intellectual and social challenges teenagers most need to master. Still development of fully mature complex thinking takes a long time. Studies show that the development of the prefrontal cortex and outer mantle of the brain continues into the early 1900.
As the wiring for logical thought is used more and more over time the connections become more robust and when this process nears completion parts of the nerves become coated in the fatty layer called the myelin sheath. Like insulation on a wire this fatty layer allows the nerve connections to process faster making rational reasoned decision making quicker and more automatic.There are many ways that psychoactive substances can alter or damage the development of the adolescent brain. Firstly psychoactive substances often target and alter functions of neurotransmitters the chemical messengers that allow nerves to communicate at their junctions interference with neurotransmitters can directly damage fragile developing neural connections. Secondly use these substances alters perception and may interfere with the developing perceptual skills and finally the habits and choices associated with the use of drugs and alcohol slowly become ingrained in the wiring of the brain.
Repeated action becomes habit and the habits of thought perception and reasoning developed in the childhood and adolescence can stay with a person throughout his or her lifetime.The mood is also altered alcohol stimulates the release of dopamine. When you chronically use foreign substances to trigger dopamine surges the body stops producing the levels that it normally needs. This means you feel worse and worse without the substance. A crucial test of the adolescent body is to figure out how much of each chemical is needed. Alcohol throws a wrench in this process. Also memory is affected by heavy alcohol interferences with the decoding of new memories. More specifically alcohol interferes with a neurotransmitter called glutamate when neurons fire together glutamate helps them wire together making it more likely to fire together in the future. Because the teenage brain is furiously firing a d wiring, glutamate is even more crucial in the adolescent brain than in the adult brain. This is why adolescents who drink a lot of alcohol end up having more memory and learning impairment than adults who drink the same amount.
Perceptual changes caused by drugs can also have long term complications for adolescent development since adolescent perceptive abilities are not fully mature. For example studies show that adults tent to use the frontal lobes or logical problem solving to determine facial expressions while adolescents us the amygdala and area which normally processes emotions such as fear and worry. It holds true in many studies that where adults use problem solving areas of the brain to perceive the world adolescents use more the primitive areas of the brain more associated with emotions and self-preservation it also is true that adult’s perception is generally more accurate. As self-help gurus are quick to point out if you do something for long enough it becomes automatic. Nowhere does this wisdom hold more truth than in adolescence. Though teens may change clothes, ideas, friends and hobbies with maddening frequency they are developing ideas about themselves, their world and their place in it that will follow them for the rest of their lives.
Adults may spend years trying to create or break even the simplest habit yet most adults find that their most profound ideas about themselves and the world were developed in high school or college. This is because by age 25 or so the brain is fully developed and building new neural connections is a much slower process. Overall changes in brain functioning in adolescents differ by substance use pattern. Research has shown that heavy drinking during adolescence can lead to decreased performance on cognitive tasks of memory attention spatial skills and executive functioning. These behavioral ramifications of heavy alcohol use may emerge as a consequence of the reduced volume of important brain structures compromised quality of white matter, and abnormalities in activation during cognitive tasks. Studies have also shown that marijuana use during adolescence can result in decreases in cognitive functioning particularly learning and sequencing scores.
In integration and interpreting the results of adolescent marijuana studies shows it is important to note that the groups are generally equivalent on task performance, and therefore the underlying brain responses in controls and user can be largely assumed to represent activity to the same mental action corresponding marijuana related changes in cognition many be related to increases in gray matter tissue volume decreases in white matter microstructural integrity and increases in neuronal activation during cognitive tastes. In sum we can reasonably rule out recent use as accounting for the served differences between substance groups given that participants in some studies have been abstinent one month or greater. Substance using adolescents have been found to differ from non-users on neuropsychological performance brain tissue volume white matter integrity and functional brain response.
Longitudinal studies are essential to fully understand neurodevelopment.Current reach suggest that substances use in adolescence leads to abnormalities in brain functioning including poorer neurocognitive performance white matter quality changes in brain volume and abnormal neuronal activation patterns. Studies have illuminated enhanced cue response in adolescent drinkers and have shown the potential to predict treatment outcomes in stimulant dependent adults. A few questions till remain such as whether heavy substance use during adolescence causes cognitive impairments and changes in neurodevelopment if and when are critical periods of heightened vulnerability to such effects and if observed abnormalities remit with reduced use. It is also important to understand if results generalize to youth with psychiatric problems other substances use histories and low socioeconomic status and to further explore implications for changes in brain activation for learning and behavioral control along with mood and psychiatric illness. Harder parametric tasks that include conditions on which behavior does differ between groups would help us better understand the cognitive domains we have observed differences on.