This chapter contains sections titled: Introduction Cellular vulnerability in bipolar disorder Phosphorous magnetic resonance spectroscopy in bipolar disorder Role of mitochondrial DNA deletion in bipolar disorder Gene expression analysis Genetics Animal models Consequence of mitochondrial dysfunction Calcium signalling Progressive cell loss Oxidative stress and mitochondrial dysfunction: a vicious cycle propelled by dopaminergic hyperactivity? Oxidative stress markers in bipolar disorder Treatment studies Effects of known treatment on oxidative systems Glutathione precursors Conclusion References Introduction Cellular vulnerability in bipolar disorder Phosphorous magnetic resonance spectroscopy in bipolar disorder Role of mitochondrial DNA deletion in bipolar disorder Gene expression analysis Genetics Animal models Consequence of mitochondrial dysfunction Calcium signalling Progressive cell loss Oxidative stress and mitochondrial dysfunction: a vicious cycle propelled by dopaminergic hyperactivity? Oxidative stress markers in bipolar disorder Treatment studies Effects of known treatment on oxidative systems Glutathione precursors Conclusion References