If true, this provides new information that may help understand the nature of the underlying biochemical mechanism and is consistent with reduced activity of PDH and/or MPC being important in some patients with bipolar disorder.19 To investigate this hypothesis further would require further detailed metabolomics studies of plasma and cerebrospinal fluid of patients with bipolar disorder, including those who are adhering to a ketogenic diet and have high levels of plasma beta ketones. This evidence concerns the gene PDP1 and bipolar disorder.