Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental condition that only rarely remits in adulthood. While several studies underlined differences between child and adult ADHD, the relationship between adult clinical presentation and early referral/treatment has been rarely investigated. In our study, 100 adults with ADHD were recruited and subdivided according to a history of referral to speciality care or treatment with methylphenidate (MPH) during childhood/adolescence. The early referral was associated with a history of disruptive behaviors during childhood/adolescence. Current ADHD symptoms were more pronounced in patients first referred during childhood/adolescence but never treated with MPH. Early MPH treatment was associated with lower rates of mood disorders and lower severity of emotional dysregulation at the time of assessment. Negative emotionality mediated the relationship between MPH treatment and mood disorders comorbidity. ADHD patients first referred during childhood/adolescence are characterized by more externalizing features than those first referred in adulthood. MPH treatment during the developmental age may have a role in preventing mood disorders in patients with ADHD, possibly by reducing emotional dysregulation.

Objectives: The treatment of emotional dysregulation (ED) poses a major challenge for clinicians managing adult attention-deficit/hyperactivity disorder (ADHD). This naturalistic longitudinal study aimed to evaluate the effects of combining mood stabilizers (MS) with standard pharmacotherapy in this population. Methods: Fifty-six adult patients with ADHD, with or without bipolar spectrum disorders, who were followed-up for at least 4 months at Pisa University Hospital were included and grouped based on the prescription of ADHD treatment with prior MS, with conomitant MS and without MS. Changes in self-reported ED, self-reported and informant-reported ADHD severity were assessed using RIPoSt-40, ASRS-v1.1, and CAARS-O:SV. Longitudinal analyses were conducted separately for each group using a pairwise one-sample paired Student’s t-test. Results: A significant reduction in ED severity was observed in those treated with methylphenidate (MPH) and concomitant MS and in those with atomoxetine (ATX) without MS. Negative emotionality and emotional impulsivity significantly decreased in both these groups, while affective instability only improved in those with MPH and concomitant MS. Self-reported ADHD improvements were significant in all groups receiving MPH, whether with concomitant, prior, or without MS. Significant changes in informant-reported ADHD severity were found in those receiving MPH with concomitant or prior MS. Conclusions: The findings highlight the benefits of concomitant MS and MPH treatment on ED, suggest a preferential effect of ATX on negative emotionality, and confirm the effectiveness of MPH for adult ADHD symptoms, regardless of additional treatment with MS. Further studies are needed to explore whether and how MS and MPH may complement each other in reducing ED.

Background/Objectives: Sex differences in adult attention-deficit/hyperactivity disorder (ADHD) remain insufficiently characterized, particularly in clinically referred samples assessed through multidimensional and multi-informant approaches. This study investigated sex differences in clinical presentation, psychiatric comorbidity, psychometric features, and ADHD severity in adults with ADHD, with a specific focus on emotional dysregulation and rating-source effects. Methods: A total of 212 consecutively recruited adults with ADHD, including 93 females and 119 males, underwent a comprehensive assessment at a tertiary referral service. Sex differences were examined across sociodemographic, clinical, comorbidity, functional, and psychometric domains. ADHD severity was assessed using both self-rated and observer-rated measures. Regression, mediation, and repeated-measures mixed-effects models were fitted to examine the role of emotional dysregulation in the association between sex and ADHD severity. Results: Females showed a higher frequency of predominantly inattentive presentation; higher rates of mood, anxiety, and eating disorders; and more pronounced emotional dysregulation, affective temperamental traits, personality-related impairment, and biological rhythm disturbances. Observer-rated ADHD severity did not differ by sex, while females reported higher self-rated ADHD severity. Emotional dysregulation was associated with both observer-rated and self-rated ADHD severity, with a stronger association for self-rated symptoms. Mediation analysis showed a significant indirect effect of female sex on self-reported ADHD severity through emotional dysregulation, accounting for 79.4% of the total association. Mixed-effects models further indicated that sex differences in ADHD severity varied according to rating source and persisted, although attenuated, after accounting for emotional dysregulation. Conclusions: Adult females with ADHD showed a different clinical profile, characterized by greater internalizing comorbidity, emotional dysregulation, personality-related impairment, and biological rhythm disturbances. Emotional dysregulation accounted for a substantial part of the higher self-reported ADHD severity observed among females, while rating-source effects suggested that sex differences in adult ADHD may partly depend on how symptom severity is assessed.