Lifetime Psychiatric Comorbidity and Diagnostic Trajectories in an Italian Psychiatric Sample

Objective: Comorbidity in psychiatric patients has been widely examined in the literature, enucleating the role in misinterpretation of symptom's root in a multi-disease background, as well as the impact on the quality of life, outcome, and healthcare effects. This research aimed to examine, in an Italian population of psychiatric patients, the diagnostic continuum in the context of lifetime psychiatric comorbidity, assessing possible differences related to the onset disorder. Method: A retrospective analysis of medical records of 458 subjects, in which various psychiatric diagnoses were represented and categorized in 16 nosographic classes, was conducted. Results: Results showed that "Bipolar disorder" (22.06%) was the most frequent diagnosis, "Eating disorder" had the earliest age onset (Mean age years = 16 +/- 1.41), and "Schizophrenia" showed the longest disease duration (Mean years = 24.20 +/- 12.76). Moreover, 54,4% of the final sample presented at least one psychiatric comorbidity in disease history, while "Other personality disorders" was the most comorbidity-associated diagnosis, representing 29% of all the cases with more than 3 past diagnoses. Heterotypic transition was observed in fairly all considered onset diagnoses, exception made for "Schizophrenia" with 75% of the subjects showing homotypic progression. Conclusions: Our results suggest a tendency to make multiple diagnoses over psychiatric patients' lifetime in the majority of cases, often escaping from the original onset nosographic domain. More generally, our findings agree with a broad consensus that describes psychiatric symptomatic dimensions rather overlapped and correlated with each other, leading to a more transdiagnostic clinical approach.