Mitochondrial disorders of energetic metabolism (MD) represent a heterogeneous group of diseases manifesting at any age and its one of a number of mitochondria syndromes that share the common characteristics of encephalopathy and myopathy. The clinical expression of MELAS (Mitochondrial Myopathy, Encephalopathy, Lactic Acidosis and Stroke-like episodes) is highly variable and ppsychiatric symptoms are rarely reported in literature even if are more common in MELAS syndrome than in the general population.

The first aim of the study is describing the clinically observed primary psychiatric symptoms in a patient affected by MELAS syndrome admitted to the Psychiatric ward. The second aim is to go back over the diagnostic process, which led, from the uncommon psychiatric symptoms and signs to the final genetic diagnosis of MD.

We report the case of a 44-year-old male with MELAS in whom psychiatric symptoms preceded the establishment of the clinical diagnosis for several months. Diagnosis was initially based on the neuroimaging and metabolic findings and subsequently confirmed with genetic analysis.

In case of aggressive and paranoid behaviour with delusions of persecution and disorganised behaviour mmitochondrial disorders deserve consideration as part of the differential diagnosis, especially if there is suspected involvement of other organ groups or positive family history of MD. There is no specific consensus approach for treating MELAS syndrome. Management is largely symptomatic and should involve a multidisciplinary team.

The authors have not supplied their declaration of competing interest.