Abstract Background Fronto-Temporal Dementia (FTD) is a neurodegenerative disorder featuring frontotemporal lobe atrophy which leads to profound changes in behavior and cognition in the affected subjects. Considering that the onset of this type of dementia is typically characterized by the development of affective symptoms, differential diagnosis between FTD and Bipolar Disorder (BD) is particularly difficult. An important overlapping feature between BD and FTD is the presence of catatonic symptoms: Catatonia is extremely frequent in FTD, and, on the other hand, BD is the psychiatric disease with the highest frequency of association with catatonic states. In this framework, it should be noted that also Autism Spectrum conditions have been reported to show high rates of comorbidity and overlapping features with BD. In addition, subjects with autistic traits were reported to show an increased vulnerability towards the development of mood and anxiety disorders, as well as increase the risk of mood episodes with mixed features, suicidal thoughts and catatonic symptoms. Case presentation We reported the case of a patient with a diagnosis of both BD and FTD who showed catatonic symptoms. Objectives The aim of this case report is to evaluate the possible role of autistic traits in the illness trajectory of BD and FTD. Conclusion This case confirms the presence of a continuum between psychiatric and neurological conditions, which should be considered as expressions of a same neurobiological system and further investigated in light of an integrative model.