Emergence of hypomania and mania following initiation of a ketogenic diet: case series.

The ketogenic diet is a century-old, evidence-based treatment for drug-refractory epilepsy, and is now also utilized as an evidence-based treatment for obesity and type 2 diabetes. Emerging research suggests that it may play a role in the treatment of serious mental illness, including treatment-resistant depression, bipolar disorder, and schizophrenia. As with any powerful therapeutic intervention, there can sometimes be side effects. This case series of 9 participants describes 8 who experienced hypomania and 1 who experienced mania within 2 months of starting a ketogenic diet. Of note, 7 of the participants did not have a prior history of a bipolar-spectrum disorder. None of the participants required hospitalization or the addition of mood-stabilizing medications as a result of these mood episodes. Nonetheless, individuals and clinicians should be aware of this risk when using the ketogenic diet, monitor for symptoms of hypomania and mania, and use appropriate strategies to manage symptoms if they emerge. These findings also raise intriguing questions and offer possible insights into the phenomenology of hypomania and mania.