ADHD is a common condition seen diagnosed usually in early childhood. Some adults recall having symptoms of ADHD while in childhood, but never really did much about it. So...what is ADHD, and why do we never hear about it as commonly in adults?
Every person is expected to meet particular milestones in neurologic development within a given period. In earlier work it was shown that children with ADHD tend to reach peak cortical thickness several years later than the typically expected time period. Significantly later than "typical" individuals (median age 10.5 years versus 7.5 years). This supports the concept that ADHD may simply be developmental delays.1
There is a common idea that ADHD is only a childhood disorder. This idea may contribute to the under recognition of this condition in adults. Its estimated that approximately 2.5-5% of the adult population has ADHD.
Symptoms of ADHD are classified three different groups: Inattentive, hyperactive and impulsive. With the previous tending to subside with age relative to the inattentive subgroup.1,3
Hyperactivity within the adult population can manifest as restlessness or inner tension, commonly it is misinterpreted as anxiety. The impulsive subgroup can be further divided into four dimensions (urgency, premeditation, perseverance, sensation seeking). Adults with ADHD without medication had:
higher urgency (tendency to act rashly)
lower premeditation (ability to consider consequences of actions)
lower perseverance (ability to stay on task when bored)
A meta-analysis examining studies of long term memory found that adults with ADHD had deficits in recall and recognition trials, suggesting that the impairment is in memory encoding (rather retrieval.) Memory encoding is how our brain processes information to condense it into packages of information (consolidation) which allow it to be store for long-term storage.
Adults with ADHD have been reported to have the largest impairments with attention, memory, and behavioral inhibition, complex attention issues being the most hallmark finding. In fact, studies using driving simulation indicate adults with ADHD have a significantly elevated daytime sleepiness. 1/3rd of all adults with ADHD have worse driving performance.1
Some common signs you may have adult ADHD:2
often fails to give close attention to details and/or makes careless mistakes.
often fails to sustain attention in tasks or play activities
often does not seem to listen when spoken to directly
often easily distracted by extraneous stimuli (including unrelated thoughts)
often fidgets with or taps hands or feet or squirms in seat
often is unable to play or engage in leisure activities quietly
often exhibits persistent pattern of excessive motor activity
often interrupts or intrudes on others
often talks excessively without appropriate response to social restraints
significant distress or impairment in social, academic, or occupational functioning
Theories of ADHD 1
The first is the behavioral neuroenergetics theory which states there is a neuronal energy insufficiency as a result of inadequate production of lactate by astrocytes.
State or vigilance regulation theory states that the core deficit in ADHD is impaired regulation of arousal. This indicates deficits in sustained attention whereas some behaviors are a result of self regulatory efforts to reach stability by increasing arousal to external stimulus.
The third main theory says impaired top-down regulation of behavior gives rise to deficits in multiple domains. It states difficulty in suppressing the default mode network (the areas active during calm, wakefulness.) Another theory explains impaired limbic regulation of reward related processing. The multiple pathway vibration can affect timing, and inhibitory responses.
What Do Imaging Studies say?
Some structural studies (looking at size and shape) have shown smaller total brain volume as well as smaller volume in a variety of subcortical (e.g. amygdala, thalamus, basal ganglia, cerebellum) and cortical (e.g. prefrontal, premotor, anterior cingulate, temporal, anterior insula, supplementary motor, primary sensorimotor) areas with the ADHD population compared with typically developing controls.
Functional studies (looking at brain activity, using electricity, blood flow) have shown that in almost all ADHD adults have high activity in areas within middle frontal and precentral gyri and low activity within the frontoparietal network and no hyperactivity within the somatomotor networks.
The traditional approach is to treat with Straterra, Concerta, Adderal, Vyvanse or other drugs, however that may not always provide a solution depending on your individual subtype and carry their own risk for dependency or other side effects.2,3
Our goal is to change our how brain networks communicate. We establish how your brain has developed and if there are any developmental delays (frontal release signs.) We can use external stimuli or train how our brains process information. Things such as reaction training, attention training activities, biofeedback, or primitive reflex attentuation exercises can all prove invaluable. Meditation or breathing exercises and other self-regulatory exercises can also be very helpful.
Maintenance of a healthy lifestyle, including a balanced, nutritious diet, and regular exercise can be very helpful. Changing your environment by modifying lightning or using headphones to reduce environmental arousal could be helpful.3
Jadidian A, Hurley RA, Taber KH. Neurobiology of Adult ADHD: Emerging Evidence for Network Dysfunctions. J Neuropsychiatry Clin Neurosci. 2015 Summer;27(3):173-8. doi: 10.1176/appi.neuropsych.15060142. PMID: 26222966.
Kooij, J., Bijlenga, D., Salerno, L., Jaeschke, R., Bitter, I., Balázs, J., . . . Asherson, P. (2019). Updated European Consensus Statement on diagnosis and treatment of adult ADHD. European Psychiatry,56(1), 14-34. doi:10.1016/j.eurpsy.2018.11.001
National Institute for Health and Care Excellence (NICE). Attention deficit hyperactivity disorder: diagnosis and management. NICE 2018