Patients with epilepsy are known to exhibit high rates of comorbid psychiatric disorders such as depression, anxiety, and other mood disorders. Little is known about the psychiatric effects of a ketogenic diet therapy (KDT) on adults with epilepsy. The objective of this study was to better understand the relationship between KDT and psychological state based on depressive and anxiety symptoms in adults with chronic epilepsy.
Adults at the Johns Hopkins Adult Epilepsy Diet Center on a modified Atkins diet (MAD) for at least one month were surveyed retrospectively. Adults who were diet naïve were given a baseline survey and an additional survey after 3 months or more on MAD. Surveys included validated measures of depressive and anxiety symptoms as well as their severity. Participant demographics, seizure frequency, and use of concomitant antiseizure drugs (ASDs), chronic anxiolytics (excluding as-needed benzodiazepines for seizure rescue only), and/or antidepressant drugs were extracted from electronic medical records.
One-hundred participants aged 19-75 enrolled in the study. Sixty participants filled out a single retrospective survey. Of 40 diet naïve participants who filled out a baseline prospective survey, 19 completed a follow-up survey while on MAD and 21 participants were lost to follow-up. Longer diet duration was significantly associated with fewer anxiety and depressive symptoms, based on psychiatric measure scores, in retrospective study participants. Lower seizure frequency was also significantly associated with less anxiety symptoms in the retrospective cohort. Prospective study participants did not experience significant change in anxiety or depressive symptoms on the diet. There was a significant correlation between higher ketone level and responder rate (≥50% seizure reduction) in the prospective cohort, although no correlation between ketone level and change in psychiatric symptoms was seen.
Psychiatric comorbidity among patients with epilepsy is quite common and can be influenced by multiple factors such as seizure frequency, the use of various ASDs, social factors, and underlying etiology. Although ketogenic diet therapies have been in clinical use for one century, the psychiatric impacts have been insufficiently explored. This study provides preliminary evidence that KDT may have a positive impact on psychological state independent of seizure reduction or ketone body production and may be influenced by longer duration of diet therapy. These results support further investigation into specific effects and potential therapeutic benefits on various psychiatric disorders.

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