Factitious disorder comorbid with borderline personality disorder and dysthymia: from medically unexplained physical symptoms to functional neurological disorder.

Introduction: In this study, we introduce the concept of comorbidity between factitious disorder (FD), borderline personality disorder (BPD), dysthymia (DY), medically unexplained physical symptoms (MUPS) and functional neurological disorder (FND) characterising patients who may tend to exaggerate physical or psychiatric symptoms of presentation to a general or psychiatric hospital with a constellation of signs that do not receive confirmation from further clinical and instrumental assessments. The similarities between these syndromes and the constant presence of borderline personality in the psychopathology make it the possible link between all these syndromes.

Materials and methods: The authors captured the typical appearance and characterisation of FD-BPD-DY-MUPS-FND (Com-1) syndrome in adult and non-forensic acute psychiatric hospitals in the United Kingdom (UK) and adjacent liaison psychiatric teams through case vignettes. Each case vignette merged similar clinical cases and was cross-analysed using information from various mental health and medical professionals and bridging primary and secondary carers' records.

Results: The findings suggest striking similarities between the syndromes making borderline personality the bridge pathology for FD, MUPS and FND. The complexity of the diagnosis of these cases is discussed in the study, together with prototypical presentations.

Conclusions: Improving the management of these often-occurring diseases requires multidisciplinary coordination across psychiatry, general care, neurology and surgery departments.