Given the considerable overlap between neurology and psychiatry, clinical neurologists regularly need to draw from their mental health reserve. Depression, anxiety, and behavioral comorbidities sprout from or grow with their primary disease or disorder to add another layer to physicians’ screening process. Epilepsy patients, says a new study, require another layer.

Nearly one in five adult epilepsy patients reported attention deficit hyperactivity disorder (ADHD) symptoms in a study published online January 15 in Epilepsia. This is four times higher than the approximate 4.4 percent rate of ADHD diagnosis in the general adult population.

Those in the study who experienced ADHD symptoms also reported higher rates of anxiety, depression and worse seizure frequency.

The study, which involved 1,361 adult epilepsy patients, was the work Alan Ettinger, MD, Epilepsy Director of Neurological Surgery, PC, and Professor of Clinical Neurology, Albert Einstein College of Medicine and his team. While the relationship between ADHD and epilepsy has been reported in children, Dr. Ettinger’s study in adults may be a first.

“To my knowledge, this is the first time that we have uncovered a phenomenon of ADHD symptoms in adults with epilepsy,” he said. “And because it’s the first time, we really do not have a firm understanding of what this represents. One thing we don’t know is whether ADHD symptoms in adults represent the same entity as a formal diagnosis of ADHD in adults or children who do not have epilepsy.” It is unknown if it is the same type of ADHD that responds vigorously to, for example, stimulants, he added.

Despite the lack of a clear understanding, there are numerous potential causes in the epilepsy patient to have causes for ADHD symptoms. Dr. Ettinger noted one possibility is that seizures themselves, or the treatments used for seizures may be contributing, in part, to ADHD symptoms. “We know that some specific anti-epileptic agents such as topiramate or valproic acid have demonstrated having a risk of impairing attention and global cognitive functioning. We also know that irrespective of a specific agent, if an individual is on anti-epileptic drug polytherapy that itself also carries the risk for cognitive impairments, including attentional difficulties.”

Yet it remains that ADHD and epilepsy could both represent independent manifestations of a potential underlying central nervous system disturbance. It is intuitive to conclude that neuropsychological difficulties such as depression, anxiety, and now ADHD symptoms, are simply just a reaction to having epilepsy, but Dr. Ettinger noted it may be that ADHD and epilepsy are independent manifestations of a condition of the brain, in which sometimes the ADHD can manifest first, followed by the manifestation of epilepsy, or vice versa.

“There is evidence to support this because a number of studies have demonstrated, in children for example, that ADHD symptoms can precede epilepsy and that ADHD symptoms in children are a potential risk factor for having epilepsy later,” he said. “In adults, the work I have done and others have done, demonstrated that psychiatric symptoms such as depression, anxiety and even psychosis can sometimes be a risk factor for manifesting epilepsy subsequently. This kind of duality has been demonstrated before and it is possible that is what is happening here in adults with epilepsy and ADHD symptoms.”

Perhaps the chief clinical concern of neurologists treating epilepsy patients with ADHD is the impact ADHD medications, notably the stimulant class—Adderall, Concerta, Ritalin, etc.—might have on seizure control. There is concern that stimulants have the potential to lower seizure thresholds.

“The predominance of the literature is actually very reassuring. In the individual with well-controlled epilepsy, the risk of incurring seizures with the use of stimulants is thought be very low, and can usually be very well compensated with AED treatment,” Dr. Ettinger said.

In individuals with active epilepsy, studies have shown benefits of stimulants for ADHD symptoms without major risk of activating the epilepsy, he noted, and the predominance of evidence is reassuring. “Future trials will be able to examine whether stimulants may have a potential beneficial role for adults with epilepsy and ADHD symptoms.”

But the impact of ADHD is only one part of the mental health equation neurologists need to solve.

“We found that individuals who had both epilepsy and ADHD symptoms were at a substantially higher risk for incurring other comorbidities, such as depression, anxiety, and diverse psycho-social difficulties, such as difficulty in family functioning, in employment issues, and so forth,” Dr. Ettinger said. “If treatments for ADHD turn out to be appropriate for the ADHD scene in adults with epilepsy, we may see the same potential benefits we see in the individual who doesn’t have epilepsy who receives treatments. This could have very important potential benefits in improving functioning, academic functioning, psycho-social functioning, and even potential benefits mood and anxiety difficulties.”

The Takeaway

“I think it is, yet again, another wake up call to the clinical community about the importance of screening for psychiatric comorbidities in adults with epilepsy. In prior studies we have demonstrated substantial rates of depression, anxiety, and in other studies, mood instability symptoms in children and adults with epilepsy,” Dr. Ettinger said. “Yet, even in this day and age clinicians in their very busy practices do not tend to screen for these very important psychiatric comorbidities.”

The study is more evidence of the importance for screening for these psychiatric comorbidities, and it has widened the range of comorbidities clinicians should be looking for, Dr. Ettinger said. There is a need for validated screening measures for ADHD symptoms in adults with epilepsy and researchers need to clarify further the nature of ADHD in adults with epilepsy. “That’s what we hope to do in our next phase of studies. We hope these studies will then provide the clinician with complete measures that they can utilize in their practices to efficiently but comprehensively screen for ADHD symptoms.

“I do want to take a cautionary note: what we have found are ADHD symptoms. This is not necessarily the same thing as an ADHD diagnosis,” he said. “That is something that needs to be clarified further in future studies that we will be pursuing.” n