The authors do not have any commercial disclosures pertinent to the content of this manuscript.
Bipolar disorder and myo-inositol: a review of the magnetic resonance spectroscopy findings
Article first published online: 14 JAN 2005
Volume 7, Issue 1, pages 1–10, February 2005
How to Cite
Silverstone, P. H., McGrath, B. M. and Kim, H. (2005), Bipolar disorder and myo-inositol: a review of the magnetic resonance spectroscopy findings. Bipolar Disorders, 7: 1–10. doi: 10.1111/j.1399-5618.2004.00174.x
- Issue published online: 14 JAN 2005
- Article first published online: 14 JAN 2005
- Received 17 September 2003, revised and accepted for publication 15 October 2004
- bipolar disorder;
- magnetic resonance spectroscopy;
Objectives: Myo-inositol is an important component of the phosphatidylinositol second messenger system (PI-cycle). Alterations in PI-cycle activity have been suggested to be involved in the pathophysiology and/or treatment of bipolar disorder. More specifically, lithium has been suggested to act primarily by lowering myo-inositol concentrations, the so-called inositol-depletion hypothesis. myo-Inositol concentrations can be measured in vivo with magnetic resonance spectroscopy (MRS).
Methods: The current review primarily examines animal and human MRS studies that evaluated the role of myo-inositol in bipolar illness and treatment.
Results: Studies have been carried out in patients who are manic, depressed, and euthymic, both on and off treatment. However, there are several limitations of these studies.
Conclusions: The preclinical and clinical MRS findings were generally supportive of the involvement of myo-inositol in bipolar disorder and its treatment. Overall, in bipolar patients who are manic or depressed there are abnormalities in brain myo-inositol concentrations, with changes in frontal and temporal lobes, as well as the cingulate gyrus and basal ganglia. These abnormalities are not seen in either euthymic patients or healthy controls, possibly due to a normalizing effect of treatment with either lithium or sodium valproate. There is also increasing evidence that sodium valproate may also act upon the PI-cycle. Nonetheless, it remains uncertain if these changes in myo-inositol concentration are primary or secondary. Findings regarding the specific inositol-depletion hypothesis are also generally supportive in acutely ill patients, although it is not yet possible to definitively confirm or refute this hypothesis based on the current MRS evidence.