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  • Phil Garvey

What Parents, Teachers and Therapists need to know about ADHD and Late Adolescence

By Phil Garvey

What is late adolescence?

You may be surprised to learn that developmentally, young people aged between 18 and 25 are viewed as being in a phase known as “late adolescence”. Significantly, under Irish law an 18- to 25-year-old is seen as an adult. Yet any individual under the age of 25 is operating from an adolescent brain.

Any individual under the age of 25 is operating from an adolescent brain.

How does an adolescent brain differ from an adult brain?

By the age of 5 a child’s brain is 90% the size of an adult's brain but it takes from that age to 25 before the brain starts to develop into an adult brain. The adult brain develops between the ages of 25 to 30. Any individual under the age of 25 is working from an adolescent brain. What makes their brain different from an adult brain? In an adult brain the prefrontal cortex, the frontal lobe (the part behind the forehead) is fully developed. In an adolescent brain it is not, adolescents operate mainly from their emotional brain in the limbic system.

In all humans the limbic system (emotional brain) develops before the prefrontal cortex as the brain develops from back to front. The main difference between the two developmentally is that in adolescence the prefrontal cortex is not interacting with the emotional region of the brain in the same way as it does in adults. Therefore, the emotional area or ‘gut response’ region in adolescents is far more active than in adults.

The Executive Brain

The prefrontal cortex (or “executive brain” as it is often referred to) is the part of the brain that is responsible for all executive functions. In other words, it brings common sense into play in any given situation. It is the part of the brain that processes information such as decision-making, planning, thinking in an abstract way, remembering, and paying attention. It evaluates risk to self and others, it evaluates consequences “if I do this then that might happen”, it helps to manage and regulate impulse. The executive brain is the responsible, rational area of the brain that can bring the emotional limbic region under control. This is the usual way the brain develops in adolescents who do not have ADHD.

The prefrontal cortex is the part of the brain that processes information such as decision-making, planning, thinking in an abstract way, remembering and paying attention.

What is ADHD?

ADHD is a common neurodevelopmental disorder, which is diverse in character meaning the behavioural symptoms present differently across males and females. It is defined as “a neuro-developmental disorder with a persistent pattern of severe inattention and/or hyperactivity/impulsivity” (APA, 2013). It has 3 recognised presentations ADHD-inattentive, ADHD-hyperactive/impulsive and ADHD-combined, with a heritability rate of 75%. Frequently ADHD is comorbid with other conditions like Autism Spectrum Disorder, Oppositional Defiance Disorder, mood disorders such as depression and anxiety and learning difficulties like Dyslexia.

What are the symptoms of ADHD?

Symptoms include emotional dysregulation, failures in working memory and organisation impairing the individual's ability to maintain attention, control their impulsiveness or organise their behaviour. Behaviours can present as social difficulties like inattention, disruption, aggression, impulsivity, poor adherence to rules or regulations, fidgeting, inability to sit still and excessive talking. It impairs intellectual concentration and performance which is indicated as a significant contributor to academic underachievement. ADHD is not linked to levels of intelligence but what it does do is interfere with the individual's ability to learn along traditional educational lines. ADHD interrupts smooth day-to-day operational functioning.

How the ADHD brain differs from the typical

We have already explored the typical path for brain development. For ADHD individuals the picture is quite different. In 2014 a study by Gizer et al., confirmed that genes for the dopamine and serotonin transporters and receptors in the brain shared common markers associated with ADHD. What that means is the brains of people diagnosed with ADHD may be under functioning due to a dysregulation of dopamine and noradrenalin. These chemical neurotransmitters transmit important messages between nerve cells in the brain and are implicated in ADHD symptomology. Studies carried out as far back as the 1920’s and replicated many times since reveal the brain waves of hyperactive and impulsive children to be slower than normal in their frontal lobes. This brain wave measure was approved by the FDA in America in 2013 as an aid to assessing an ADHD diagnosis, supporting the evidence that slow-wave prefrontal brain activity was a bio-marker for ADHD.

Why parents, teachers and therapists need to know about brain development and ADHD

What all this means for the late adolescent from aged 15 to 25 is that there is a delay in the development of the prefrontal cortex. The Limbic region of the brain develops at a faster rate than the frontal lobe in ADHD individuals. Wilens et al., (2018) suggest that it is the gap in rates of development between the limbic and frontal lobes of the brain that causes the extremes of behaviour in late ADHD adolescents. Just when an ADHD adolescents symptoms are worsening around 18 they are declared adults and all supports are withdrawn. They are expected to be able to be responsible for themselves. The gap between the behaviour of their peers who do not have ADHD and those that do starts to widen. Parents are left struggling to support and help their ADHD children who they no longer have any authority over in law. Parents are left to their own devices managing and financially bailing out their late ADHD adolescent when they get themselves into trouble with no support, recognition and even less empathy or understanding from any official quarter.

What the evidence tells us about late adolescence and ADHD

Evidence from studies speaks for itself. Many ADHD late adolescents live a life in chaos. ADHD adolescents start smoking, drinking alcohol, and doing drugs younger than their peers. They are more likely to be involved in more road traffic accidents, have worse driving habits and more traffic offences than their peers. They are at higher risk of injuries and hospital admissions than their peers. Evidence shows that they engage in risky sexual activity younger and have more sexual partners than their peers. They are also more likely to have more pregnancies and greater incidences of sexually transmitted diseases earlier than their peers without the condition. They are 50% more likely to experience peer rejection because of their behaviours unlike their peers who have not got the condition whose experience is around 15%. Most worrying of all studies show that ADHD is found to be connected to early criminality leading to a three-fold risk of early arrest, conviction, and imprisonment. Recidivism is also higher among ADHD offenders. Young et al., (2015) state that almost 25% of the prison population in their study demonstrated ADHD symptoms.

Interventions to empower the ADHD adolescent

CBT and Solution Focused Therapy

A multi-modal approach involving the ADHD adolescent, parents, therapist, and teachers can empower the adolescent to control their symptoms. One to one Cognitive Behavioural therapy (CBT) and Solution Focused therapy allow the therapist to teach the ADHD person strategies like identifying their specific deficits and strengths that aid in the management of their individual behaviours. Psycho-education and skills acquisition help to improve symptoms in areas of organisation, mood, self-esteem, and other symptoms. Anxiety and depression levels also reduce. Anger management training gives the ADHD individual tools to enable them to better control their behaviours.

Other interventions

Mindfulness interventions are known to reduce symptoms. Regular strenuous exercise helps to focus the mind, rugby, basketball, football, hurling, swimming, going to the gym all aid concentration. Drama, dancing, singing, playing a musical instrument all help to instil a discipline, a way of improving participation, which can help with social acceptance.

What can schools and colleges do to accommodate the ADHD late adolescent?

It is not just the ADHD late adolescent that needs to change, therapies that focus on changing the environment and system rather than the adolescent can have a greater impact.

Schools and colleges have already recognised this and have adapted to give the ADHD student a fairer chance of success. For those ADHD individuals in college making the connection with the disability services within colleges can make a significant difference in terms of aids like laptops with specific technology on board designed to aid the ADHD student, smaller rooms in which to do exams with less distraction, noise blocking headphones, repositioning of tables to better manage distraction all acknowledging that traditional paths do not suit ADHD students.

Final Thoughts

While schools and colleges recognise the symptoms of ADHD and have made efforts to adapt to aid the late adolescent on the educational front the same cannot be said for the law and how the ADHD adolescent is treated once they enter the system. No efforts are made on their behalf to really understand what the ADHD late adolescent must contend with, there is no facility or alternative to a fine or custodial sentence. There is no meaningful third way like therapy, psycho-education or facility to aid the ADHD adolescent when they are at their most vulnerable and at the mercy of brain developments they cannot control.

Eventually the prefrontal cortex developmentally catches up and symptoms can reduce or morph over time. The problem is that by that stage the damage to the late ADHD individuals life and prospects can be compromised by what they as individuals have had to contend with in terms of their own ADHD behaviours during this delayed developmental period.


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