By: Annemarie DeChellis
While multiple psychiatric and neurobehavioral disorders occur alongside epilepsy, attention-deficit hyperactivity disorder (ADHD) occurs at the highest rate. About 30 to 40% of children with epilepsy have ADHD compared to the 7 to 9% of children from the general population who are diagnosed with ADHD (Abramowitz & Hollingsworth, 2018; Dunn et al., 2003; Hermann et al., 2007; Reilly et al., 2014). Although ADHD is commonly thought of as a childhood disorder, ADHD is prevalent among adult populations. About 20% of adults with epilepsy have ADHD whereas 2.5 to 4% of the general adult population have ADHD (Abramowitz & Hollingsworth, 2018).
What is ADHD?
ADHD is a neurodevelopmental disorder characterized by cognitive and behavioral symptoms such as inattention, impulsivity, hyperactivity, and disorganization. ADHD is divided into three subtypes: predominantly hyperactive-impulsive, predominantly inattentive, and combined (Abramowitz & Hollingsworth, 2018; Center for Disease Control and Prevention, 2021; Kolar et al., 2008). Predominantly hyperactive-impulsive ADHD is characterized by fidgeting, difficulty sitting still, interrupting others, and feeling restless. While, predominantly inattentive is characterized by difficulty finishing tasks and staying focused, getting bored easily, avoiding tasks that require heavy focus, and forgetting important details. Combined ADHD is characterized by an equal distribution of the symptoms for inattentive and hyperactive-impulsive ADHD (Bhandari, 2020; Center for Disease Control and Prevention, 2021). Despite ADHD being one of the most commonly studied psychological disorders, the precise cause of ADHD is still unknown. However, genetics may play a role as low levels of dopamine have been reported in those with ADHD, and ADHD often runs in families (Cleveland Clinic, 2019; Johns Hopkins Medicine, n.d.).
ADHD can have a significant impact on daily life and can create challenges in school, work, and relationships. Treatment options for ADHD typically include medication and behavior therapy. Stimulant medications are most commonly prescribed to treat ADHD with a successful reduction of symptoms for about 70 to 80% of people (Center for Disease Control and Prevention, 2020). For people with epilepsy, there have been concerns over stimulant medication triggering seizures. However, the risk appears minimal and stimulant medication can reduce ADHD symptoms for people with epilepsy (Abramowitz & Hollingsworth, 2018).
ADHD and Epilepsy
The link between ADHD and epilepsy is not well understood. However, similarities in neurological dysfunction and executive functioning may contribute to the association (Dunn et al., 2003). Interestingly, ADHD in people with epilepsy differs statistically from the general population. Within the general population combined ADHD is the most common subtype, whereas inattentive ADHD is the most common for people with epilepsy (Dunn et al., 2003; Ekinci et al., 2017; Hermann et al., 2007). The distribution of ADHD differs by sex as well. Contrary to the general population where boys are diagnosed more frequently than girls, ADHD is more evenly distributed between boys and girls with epilepsy. Research has not shown specific seizure types to correlate with ADHD (Dunn et al., 2003).
While ADHD occurs at a higher rate among people with epilepsy, many remain undiagnosed. A study conducted in the United Kingdom to assess the prevalence of neurobehavioral comorbidity in children with epilepsy found that two thirds of children with neurobehavioral disorders were undiagnosed prior to the study (Reilly et al., 2014). As suggested by Reilly et al. (2014), ADHD may go undiagnosed due to “diagnostic overshadowing.” In other words, having a neurological disorder such as epilepsy overshadows or trumps concern over psychiatric disorders. Furthermore, inattentive ADHD is often diagnosed late or not at all because the symptoms are not as distinguished and noticeable compared to the hyperactive form of ADHD (Cleveland Clinic, 2019). With inattentive ADHD being the most common type of ADHD for people with epilepsy, this may contribute to the prevalence of undiagnosed ADHD.
The Importance of a Proper Diagnosis and Treatment
Children with epilepsy and ADHD have reported poorer quality of life compared to children with only ADHD or epilepsy (Ekinci et al., 2017). This finding emphasizes the need to reduce the burden of living with ADHD and epilepsy through both effective treatment and support from others, including healthcare professionals. Given the frequency of cognitive and behavioral disorders occurring alongside epilepsy, there have been calls to make neurobehavioral assessments more accessible and regularly incorporated in the treatment process for childhood epilepsy (Ekinci et al., 2017; Reilly et al., 2014). Receiving the correct diagnosis of ADHD has been reported to provide patients with a feeling of relief and an explanation for difficulties and recurring problems they had been experiencing. In addition, the proper diagnosis can improve quality of life by not only receiving assistance from mental health professionals, but also by providing deeper insight and understanding of one’s self and behavior (Hansson Hallerod et al., 2015).
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