Evidence of altered metabolism of cellular membranes in bipolar disorder comorbid with post-traumatic stress disorder

•To our knowledge, this is the first 1H MRS study to investigate the biochemical alterations related to post-traumatic stress disorder (PTSD) in patients with bipolar disorder I (BP-I) using a multi-voxel approach with a high spatial resolution and absolute quantification.•We found significantly higher GPC+PC levels in the caudate head and putamen of patients with BP-I and PTSD comorbidity compared to BP-I without PTSD subjects and HC.•This is the first study to investigate metabolic alterations related to PTSD in BP-I patients using a multi-voxel 1H MRS method with high spatial resolution and absolute quantification. The elevated GPC+PC in the caudate and putamen may reflect pathological and imbalanced metabolism of cellular membrane phospholipids in these regions for BP-I and PTSD comorbidity.