• Borderline Personality Disorder
• Emotional Dysregulation
• Bipolar Disorder
• Neurodevelopment
• ADHD

Background : Attention Deficit/Hyperactivity Disorder (ADHD) is a clinical condition typically diagnosed in childhood characterized by inattentiveness, hyperactivity and impulsivity. In adulthood, ADHD shows a heterogeneous presentation with atypical features, less severe externalizing and hyperactive symptoms, persistence of emotional dysregulation (ED) and inattentiveness and high rate of psychiatric comorbidities. In adult ADHD, ED, a symptomatologic dimension characterized by a low frustration tolerance, impulsivity, irritability and mood lability may predominate the clinical presentation. Many of these symptoms largely overlap with the DSM-5 diagnostic criteria of Cluster B Personality Disorder (BPD). The aim of this study is to investigate the correlations between the presence of ED and BPD in a sample of adult ADHD patients and to explore the relationships of clinical and temperamental characteristics of these patients with bipolar spectrum comorbidities.

METHOD: We enrolled 102 adult patients with ADHD using as assessing tools the Diagnostic Interview for ADHD in Adults (DIVA 2.0), the Conners Adult ADHD Rating Scales (CAARS), the brief Temperament Evaluation of Memphis, Pisa, Paris and San Diego–M (brief TEMPS-M), the Reactivity Intensity Polarity Stability Questionnaire (RIPoSt), the Barratt Impulsiveness Scale (BIS-11), the Adult Self-Report Scale (ASRS-v 1.1), the Functioning Assessment Short Test (FAST), the Morning Evening Questionnaire (MEQ), the Brief Psychiatric Rating Scale (BPRS), the Hypomania Checklist-32 (HCL-32) and the World Health Organization Disability assessment schedule 2.0 (WHODAS 2.0). Using the RIPoST mean score we distinguished two groups with different levels of ED, a Low-Emotional Dysregulation (L-ED) and an High-Emotional Dysregulation (H-ED). We have also divided the sample in subjects with and without BPD and subsequently patients with and without bipolar diathesis and we compared them.
RESULTS: With multiple logistic regression analyses, we observed that an H-ED pattern, determined by RIPoST Total score, is mainly associated with female gender (p=0.011), irritable (p=0.004) and cyclothymic temperament (p<0.001) and HCL-32 total score (p=0.012). We have also obtained significant findings regarding associations between BPD and BP in ADHD patients. Particularly, bipolar spectrum (p=0.006), female gender (p=0.002), BPRS total score (p=0.001) and HCL-32 total score (p=0.026) were mostly associated with BPD+ patients, while the most discriminant factor between BD and non-BD patients with ADHD seemed to be the comorbidity with borderline personality disorder (p<0.001).

CONCLUSION Our results suggest that high levels of ED can represent a risk factor for the development of a subtype of adult ADHD characterized by a severe clinical presentation and high rates of comorbid mood and anxiety disorders. We hypothesized that the strong association and the co-occurrence between these supposedly distinct syndromes, BD, BPD and ADHD, may be founded on a shared common neurobiological basis. ED may represent the shared core psychopathological dimension. Further longitudinal research is necessary in order to confirm the role of ED in adult ADHD.