Psychosis as a manifestation of cerebral involvement in mitochondrial disorders

Introduction: Cerebral manifestations in mitochondrial disorders (MIDs) not only include neurological abnormalities, cognitive impairment, or dementia, but in single patients also psychiatric abnormalities, in particular psychosis. Problem formation: Is there a difference between mitochondrial and non-mitochondrial psychosis? How can mitochondrial and non-mitochondrial psychosis be delineated? Which is the prevalence of mitochondrial psychosis? Which is the therapy of mitochondrial psychosis? Problem solution: Clinically, there is often no difference between mitochondrial and non-mitochondrial psychosis. In such cases mitochondrial psychosis can be delineated from non-mitochondrial psychosis only by additional clinical and instrumental neurologic investigation and investigations for visceral abnormalities. Mitochondrial psychosis is most prevalent in MELAS syndrome, and rarely occurs in KSS, CPEO, or non-syndromic MID. The prevalence of psychosis in MELAS syndrome, the MID most frequently associated with psychosis, is 7-17%. Therapy of mitochondrial psychosis is not at variance from therapy in patients with non-mitochondrial psychosis, but mitochondrion-toxic drugs, particularly haloperidol and risperidone, should be avoided. Conclusions: MIDs should be included in the differential diagnoses of psychoses. Mitochondrial psychosis should be suspected if there is multi-system involvement and if there are structural abnormalities on cerebral imaging.