• ASD
• autism spectrum disorder
• high-functioning autism
• HFA
• bipolar disorder
• comorbidity
• BD
• Bipolar disorder other specified
• BD-OS

Background: Autism spectrum disorder (ASD) is a wide broad pervasive neurodevelopment condition that shares persistent deficits in social communication and social interactions; restricted, repetitive patterns of behaviours, interests or activities, but with several differences both in cognitive and language performances and global functioning. ASD clinical features are heterogeneous and are a consequence of different levels of functioning. Low functioning (LFA) and high functioning (HFA) clinical forms of ASD are classically distinguished according to a dimensional approach. HFA is often ignored during childhood and a proper diagnosis does not occur until adulthood, when individuals come to the clinician's attention by the emergence of psychiatric comorbidities, especially mood disorders. Bipolar disorder (BD) and HFA association in adult clinical populations has been confirmed by a growing number of studies. However, identifying and treating BD is a clinical challenge in HFA individuals, as is recognizing autistic traits in patients with BD, and requires careful assessment and adequate knowledge of both disorders. Indeed, the atypical clinical presentation of mood disorders in HFA, together with the overlap of some features of ASD with symptoms of other mental illnesses, can lead to inaccurate diagnoses and thereby, improper treatment. In spite, current literature reports the frequent co-occurrence of bipolar disorder (BD) and high-functioning autistic spectrum disorders (HFA), demographic and clinical characterization of BD in adult subjects are still lacking.
Aim of the study: We described demographic and symptomatologic features, as well as response to pharmacological treatments in individuals with BD-HFA. Moreover, in order to identify specific clinical features, we compared demographic and clinical features of BD in patients with and without co-existing HFA.
Methods: A cross-sectional naturalistic study was performed in a sample of 62 patients aged ≥ 18 with BD-HFA comorbidity. We evaluated demographic and clinical features, comorbidity, family history, severity of psychopathology, temperament, response to pharmacological treatment and overall functioning using the Semi-Structured Interview for Mood Disorder-Revised (SIMD-R), the brief version of temperament evaluation of Memphis, Pisa, Paris, and San Diego self-questionnaire (TEMPS-M), the Clinical Global Impression (CGI) and Global Assessment of Functioning (GAF) scales. Clinical diagnosis of HFA was confirmed by the Autism Quotient (AQ), the Empathy Quotient (EQ) and the Ritvo Autism Asperger Diagnostic Scale-Revised (RAADS-R) scales. Afterwards, we compared our sample with a BD control group without ASD (N-ASD).
Results: In comparison with patients without coexisting ASD, patients with HFA reported higher rates of bipolar disorder other specified (BD-OS), with early age onset of mood disorder, more hospitalization and psychiatric treatment, with lower rates of full remission between the episodes, higher cyclothymic temperamental rates at the TEMPS-M questionnaire, compared to N-ASD. ADHD and anxiety disorders were the main comorbidities. Family history for BD and depression disorders were highly represented. Remarkably rates of mood destabilization and adverse effects with the use of antidepressants and antipsychotics were observed.
Conclusions: Our results suggest that BD in HFA adult is characterized by specific demographic and clinical hallmarks. BD-HFA co-existence was associated with worse prognosis and poor response to antidepressant and antipsychotic treatments. Further research is needed to confirm our observation in a larger samples and to better evaluate longitudinal course and long-term treatment outcome.