Substance Use Disorder Reduces Antiepileptic Medication Success

Edward Han-Burgess, MS, MBA, CFA

Psychiatric disorders and substance use disorders might reduce the efficacy of antiepileptic drugs among patients with epilepsy, according to findings presented American Epilepsy Society (AES) Annual Meeting in New Orleans.

Investigators from UCB Pharma reviewed the data of more than 175,000 patients with epilepsy in order to determine the likelihood of successful antiepileptic drug treatment in these patients. The investigators said that these drugs are well-tolerated and achieve seizure control, but only through a process of trial and error which can last years. This process, they wrote, may be further complicated by patients with epilepsy who have comorbid psychiatric disease or substance use disorder.

The investigators analyzed the data searching for treatment success and comorbid psychiatric diseases, including anxiety, schizophrenia, depression, and bipolar disorder, or substance use disorder including the use of substances, opioids, or cannabis. The investigators also categorized the patients by age, creating groups of 16-34-year-olds, 35-64-year-olds, and those over 65 years of age.

The investigators defined treatment success using a proxy, treatment stability, and the use of continuous treatment drug for longer than 12 months without the addition of another drug, though they allowed for dose adjustments.

The treatment success rate for all the patients with epilepsy was 50.8%. In the youngest cohort, the success rate was 36.3%, followed by 44.9% in the 35-64-year-old group. Patients 65 years and older had the highest treatment success rate at 59.2%.

Compared with those rates, the investigators said hypertension or diabetes presence did not affect the likelihood of antiepileptic drug treatment success. However, any psychiatric disorder or substance use disorder did reduce the likelihood, they said. The decrease amount was relatively similar among the 3 age groups as well as in most psychiatric or substance use disorder comorbidities; though, the investigators said, the exceptions were suicidal behaviors, substance abuse, and opioid abuse. Those subcategories saw age-related differences and the treatment success likelihood was lowest among the youngest patients.

“What we found in compiling associations is that psychiatric disorders and substance use disorders as comorbidities in people with epilepsy may reduce antiepileptic drug treatment success, and of those, the biggest impacts were among young (age 16 to 34) high users of opioids,” study author Edward Han-Burgess, MS, MBA, CFA, told MD Magazine®. “Understanding this helps us to identify comorbidity risk factors within subpopulations of people living with epilepsy, empowering us to identify areas of needs where we can create patient value.”

The investigators said that these findings need more research to further determine whether treatment stability or the proxy for treatment success actually corresponds to successful clinical outcomes. Plus, they said the retrospective nature of the study and small sample size limit the overall interpretation and generalizability of the results.

Screening for psychiatric comorbidities or substance use disorders in patients with epilepsy—especially younger ones—could be helpful in making treatment decisions for these patients, Han-Burgess continued.

“We know everyone’s patient journey is different,” Han-Burgess said. “This research allows us to focus on how these factors associate with treatment outcomes and understand where the incremental risks are for patients, helping us think about ways we may optimize or improve outcomes using big data.”

The abstract, “Impact of psychiatric and substance use disorder comorbidity on treatment success among patients with epilepsy —retrospective analysis of claims data,” was published on the AES website.