A small clinical trial is adding to growing interest in whether changing the body’s metabolism through diet could support care for people with serious mental illness.
The study, published in Schizophrenia Bulletin, tested a ketogenic diet in people with schizophrenia-spectrum or bipolar-1 disorders. After one month, participants assigned to the ketogenic diet had stronger improvements in several metabolic markers than those who continued their usual diet. A smaller group that stayed on the diet for four months also showed improvements in psychiatric symptoms and cognitive measures, but that longer phase did not include a control group.
That distinction matters. The findings suggest a medically supported ketogenic diet may be feasible and worth studying further in serious mental illness, especially because many people with these conditions also face metabolic health risks. But the study does not show that keto treats psychosis on its own, replaces medication or should be tried without medical supervision.
Ketogenic diets are very low in carbohydrates and high in fat, shifting the body toward using ketones for energy. In this trial, researchers tracked whether participants reached ketosis and reported that most daily-tested participants did so during both the one-month randomized phase and the four-month extension. The release also reported no significant side effects from the diet.
During the controlled part of the study, 47 of 58 enrolled participants completed the one-month comparison between the ketogenic diet and diet as usual. Researchers found that higher ketone levels were associated with lower blood glucose and fewer depression symptoms, even after accounting for weight loss. That finding raises the possibility that ketosis itself may play a role in some of the changes observed, though the study was not large enough or long enough to prove that.
The four-month extension was more encouraging but also less definitive. Twenty-five participants chose to continue the ketogenic diet, and researchers reported sustained metabolic improvements along with reductions in depression and schizophrenia symptoms and better cognitive performance. Because everyone in that phase was on the diet, the results cannot show whether the improvements were caused by the diet, the extra support involved in following it, time, medication changes, participant motivation or other factors.
“The improvement we saw in cognitive and psychological symptoms is particularly important in people with psychotic disorders, because current medications that address their psychosis don’t address their overall mental wellbeing, including cognitive or depressive symptoms, which can be debilitating,” said study lead Judith M. Ford, PhD, professor of psychiatry at UCSF and the Weill Institute for Neurosciences.
Ford also noted that the results point to the need for larger, longer, fully controlled trials before researchers can know whether the benefits hold up in a broader population.
That caution is especially important because ketogenic diets can be difficult to follow and may not be appropriate for everyone. People with serious mental illness may also be taking medications that affect appetite, weight, blood sugar, cholesterol or other metabolic markers. A major diet change could require coordination among a psychiatrist, primary care clinician and registered dietitian.
The study fits into an emerging area sometimes called metabolic psychiatry, which explores how energy use, blood sugar regulation, inflammation and other metabolic processes may relate to brain health and psychiatric symptoms. Researchers are still working to understand whether changing metabolism through diet can meaningfully improve mental health outcomes, who might benefit most and how to make such interventions safe and sustainable.
The study was funded in part by the National Institute of Mental Health and Baszucki Group, a philanthropic organization that supports research into metabolic approaches to mental health.