• cognitive comorbidities
• Montreal Cognitive Assessment
• Newcastle Mitochondrial Disease Adult Scale
• Primary Mitochondrial Diseases
• psychiatric comorbidities
• Symptom-Checklist-90-Revised

Mitochondria are essential eukaryotic organelles, responsible for a wide variety of metabolic cell pathways. The most important is oxidative phosphorylation (OXPHOS), the process that produces ATP.
Primary Mitochondrial Diseases (PMDs) represent a rare and very heterogeneous group of metabolic diseases affecting mitochondrial metabolic pathways. These conditions frequently involve organs highly dependent on aerobic metabolism, including the nervous system, and are often associated with psychiatric and cognitive comorbidities.
This study aimed to determine the prevalence of psychiatric symptoms and cognitive impairment in our cohort, by administering the Symptom Checklist-90-Revised (SCL-90-R) and the Montreal Cognitive Assessment (MoCA).
We studied a cohort of 38 Italian adult patients affected by genetically diagnosed or clinically suspected PMDs, determining for each subject the severity of the disease with the Newcastle Mitochondrial Disease Adult Scale (NMDAS). MRI data were available for 30 patients, 36 patients were administered SCL-90-R, whereas 30 were administered the MoCA.
Overall, we found that in our cohort both cognitive and psychiatric comorbidities were very frequent. In addition, a statistically significant correlation between psychiatric symptoms and disease duration was observed, along with other non–significant trends.
Conclusions: these findings support the importance of integrating cognitive and psychiatric assessments into routine clinical evaluation of patients with PMDs, in order to improve the management of these incurable and often disabling diseases.