ADHD

Attention deficit hyperactivity disorder, ADHD, is one of the most common neurodevelopmental disorders in children and adolescents.

There are three ways ADHD presents itself: inattentive presentation (ADHD-I), hyperactive-impulsive presentation (ADHD-H), and combined presentation (ADHD-C).

Inattentive presentation is when the individual finds it hard to organise or finish a task, pay attention to details or follow instructions. Meta-analysis, a statistical method to combine results of different studies, indicates that inattention is strongly associated with academic impairment, low-self esteem and negative occupational outcomes. Hyperactive-impulsive symptoms are associated with peer rejection, aggression and restlessness. Combined presentation is the combination of inattentive and hyperactive-impulsive presentation symptoms.

With it being first diagnosed in childhood and lasting into adulthood, it occurs in 5.9% of youth and 2.5% adults. However, there are disparities in ADHD diagnosis. The number of ADHD diagnoses are about 2x higher in the most deprived areas compared to more privileged areas. This links to how a higher proportion of people are beginning to access private healthcare for ADHD due to long waiting lists for assessment in the public sector. This creates healthcare inequalities as those who are unable to afford private healthcare may suffer with undiagnosed and untreated symptoms, creating even longer significant disruption to their personal and professional lives.

Factors correlated with ADHD:

Although there is a very high level of evidential support between the emergence of ADHD and environmental factors, there are possibilities that these associations remain due to combined genetic and environmental effects rather than solely on the environment. Thus, these factors are viewed as correlations rather than causes, they aren’t specific to ADHD.

Environmental factors correlated to ADHD occur very early in life, in the foetal or early postnatal period – the first 24 hours from birth where the infant’s physiology adapts. Rare cases such as extreme deprivation early in life, single genetic abnormality or traumatic brain injury early in life helps to understand the causes of ADHD but isn’t useful in diagnosing the disorder. Postnatal and foetal development factors such as premature delivery, low birth weight and alcohol and tobacco use during pregnancy are also correlations.

As well as the environment, genetics are correlated with ADHD, in a genomewide study, an international team analysed DNA from over 20,000 people with ADHD and over 35,000 without ADHD from the US, Europe, Scandinavia, China and Australia. They discovered many small genetic risk factors and combined them with one another, forming a high polygenic risk score for most cases of ADHD. Polygenic risk scores are widely used to determine the likelihood of your risk due to your genes towards a specific disease.

Medicinal and non-medicinal treatments for ADHD

As helpful as fMRI scans are with evaluating the blood flow in the brain and help to better understand medications used for ADHD as well as helping to better identify environmental and prenatal factors which affect symptoms, they cannot yet reliably diagnose ADHD.

A meta-analysis of 14 fMRI studies with 212 participants reported that medication treatment for ADHD made the brains of youth with ADHD function similarly to those without the condition. Their brains were functioning correctly in areas involved in the control of cognition, which is typically disrupted in people with ADHD. Medicines didn’t directly affect the structure of the brain; this is because instead they raise the level of norepinephrine in the brain which reduces the levels of hyperactivity, inattentiveness and impulsivity in the brain. However, as soon as the drug wears off, the symptoms return.

Non-medicinal treatments such as behavioural treatments vary with age, however for younger children parents are trained to improve their method of disciplining and interaction with their children. For adolescents and adults, therapy helps ADHD patients improve skills such as organisation. Cognitive behavioural therapy helps the person with ADHD to become more aware of attention and concentration challenges, aiming to also work on skills to help improve focus. Long term, behavioural treatments help develop accommodations and strategies for dealing with the effects.

Bibliography:

https://www.sciencedirect.com/science/article/pii/S014976342100049X?via%3Dihub

https://pubmed.ncbi.nlm.nih.gov/33549739/

https://www.cdc.gov/ncbddd/adhd/facts.html#ref