Ketogenic Diet and Mental Health: New Research on Psychosis, Schizophrenia and Bipolar Disorder

My goal has always been to sit somewhere between clinical science and real world experience. I am constantly reading one study after another, but research findings do not always translate neatly into clinical practice. Human beings are more complicated than a research protocol. This is particularly true in metabolic psychiatry, an area I have followed closely because I believe nutrition and metabolism can profoundly influence how the brain functions.

The ketogenic diet is one of the most powerful metabolic interventions I have used, but that does not mean every client responds in the same way. One person may have IBS, another may have high levels of histamine producing bacteria, while someone else may struggle with constipation, hormonal changes, nutrient deficiencies or the metabolic effects of medication. There is no single ketogenic prescription that works for everyone. The research gives us a framework, but clinical practice requires us to adapt that framework to the individual sitting in front of us.

Over the years, I have used different tools to make ketogenic metabolic therapy more practical and tolerable. Depending on the person, this may include gradually lowering carbohydrates, changing the types of fats being consumed, increasing prebiotic fibre, supporting the gut microbiome, correcting nutrient deficiencies or occasionally using MCT oil or exogenous ketones. These additions are not a substitute for the diet itself, but they may help someone reach and maintain nutritional ketosis without ignoring the rest of their physiology.

This is why a newly published study involving Dr Shebani Sethi caught my attention. Abram and colleagues conducted the first randomized controlled trial examining the metabolic, psychiatric and cognitive effects of a ketogenic diet in people with schizophrenia spectrum disorders or bipolar I disorder. Fifty eight participants were initially randomized to either a ketogenic diet or their usual diet for one month. A smaller subgroup of 25 participants went on to complete four months of ketogenic therapy. The participants were living in the community, making this particularly relevant to real world clinical practice rather than a tightly controlled inpatient setting.

After one month, the ketogenic group had improvements in weight, HbA1c and insulin resistance compared with the diet as usual group. Among those who continued the ketogenic diet for four months, the researchers also reported improvements in positive and negative psychotic symptoms, depressive symptoms and cognitive performance. Importantly, higher blood ketone levels were associated with greater improvements in depressive symptoms and prediabetic markers. Weight loss itself was not associated with the psychiatric improvements. This raises the possibility that ketosis may be doing something therapeutically relevant beyond simply helping people lose weight.

However, the study needs to be interpreted carefully. Only the first month was randomized and controlled. The four month results came from a smaller subgroup and were compared with their own baseline rather than with a continuing control group. We therefore cannot conclude that a ketogenic diet treats every person with schizophrenia or bipolar disorder, nor can we say that higher ketones will automatically produce better outcomes for every psychiatric condition. What this study gives us is a promising clinical signal and a strong reason to conduct larger and longer randomized trials.

One possible explanation involves brain energy metabolism. Some psychiatric disorders are associated with alterations in cerebral glucose metabolism, insulin signalling and mitochondrial function. Ketones provide the brain with an alternative fuel and may also influence oxidative stress, inflammation, neurotransmitter balance and cellular signalling. It would be too simplistic to say that an inability to use glucose directly causes mental illness, but impaired energy regulation may be an important part of the biological picture for some individuals.

What I find especially important is that mental health improvements may not depend on weight loss. People often assume that the benefits of a ketogenic diet are simply a consequence of becoming lighter. This study suggests that the metabolic state of ketosis itself may matter. That reflects what many people describe in practice: clearer thinking, more stable energy and, in some cases, changes in mood that become noticeable before substantial weight loss occurs.

At the same time, ketogenic metabolic therapy should not be reduced to eating more butter, meat and cheese. A diet can produce ketones while still being poorly suited to the person following it. For someone with IBS, constipation, histamine intolerance or an altered microbiome, the types of fat, fibre, vegetables and fermented foods included in the diet may be just as important as the ketone number. Clinical ketosis has to be considered alongside gut function, nutrient status, sleep, hormones, medication and the person’s ability to sustain the intervention.

This is where I believe the space between research and clinical practice matters most. Research helps us understand what may be possible. Clinical care helps us work out how to make it possible for an individual person. Ketogenic metabolic therapy is not yet a cure for schizophrenia, bipolar disorder or depression, and it should not be used as a reason to stop psychiatric medication without appropriate medical supervision. But it deserves to be studied and taken seriously as a potential adjunctive treatment that addresses metabolism as part of mental health.