Although childhood-onset psychiatric disorders are often considered as distinct and separate from each other, they frequently co-occur, with partial overlapping symptomatology. Autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) commonly co-occur with each other and with other mental disorders, particularly disruptive behavior disorders, oppositional defiant disorder/conduct disorder (ODD/CD). Whether these associated comorbidities represent a spectrum of distinct clinical phenotypes is matter of research. The aim of our study was to describe the clinical phenotypes of youths with ADHD with and without ASD and/or ODD/CD, based on neuropsychological and psychopathological variables. One-hundred fifty-one participants with ADHD were prospectively recruited and assigned to four clinical groups, and assessed by means of parent-reported questionnaires, the child behavior checklist and the behavior rating inventory of executive functions. The ADHD alone group presented a greater impairment in metacognitive executive functions, ADHD+ASD patients presented higher internalizing problems and deficits in Shifting tasks, and ADHD+ODD/CD subjects presented emotional-behavioral dysregulation. Moreover, ADHD+ASD+ODD/CD individuals exhibited greater internalizing and externalizing problems, and specific neuropsychological impairments in the domains of emotional regulation. Our study supports the need to implement the evaluation of the psychopathological and neuropsychological functioning profiles, and to characterize specific endophenotypes for a finely customized establishment of treatment strategies.

Background: Catatonia is a transdiagnostic syndrome marked by motor, behavioral, and autonomic disturbances. Corticosteroids, commonly used to treat suspected neuroinflammatory conditions, may rarely precipitate or exacerbate psychiatric symptoms, including catatonia, in children and adolescents. Methods: We describe two adolescent girls who developed catatonia following corticosteroid therapy for suspected encephalitis, despite negative cerebrospinal fluid and blood markers. Clinical courses, diagnostic workups, and therapeutic strategies (including benzodiazepines, antipsychotics, and immunomodulatory treatments) are detailed. A literature review of steroid-induced neuropsychiatric complications in pediatric populations was also performed. Results: Both patients experienced temporal association between corticosteroid exposure and onset of catatonia. Standard first-line treatments were insufficient, and stabilization required antipsychotic therapy, including clozapine. Gradual improvement in baseline clinical status and recovery of lost functional abilities were observed during follow-up. These cases underscore that corticosteroid-induced catatonia, though rare compared to steroid-related psychosis, can occur in adolescents and may complicate the differential diagnosis of neuropsychiatric syndromes. Conclusions: While corticosteroids remain essential for treating neuroinflammatory conditions, clinicians should be aware of the potential for severe psychiatric adverse effects, including catatonia, in pediatric patients. Careful differential diagnosis, interdisciplinary collaboration, and timely psychiatric intervention are critical to avoid iatrogenic worsening. Further research is needed to clarify underlying neurobiological mechanisms and identify markers of vulnerability, promoting safer and more personalized treatment approaches in children and adolescents.

Background/Objectives: Adolescents with attention-deficit/hyperactivity disorder (ADHD) and bipolar spectrum disorders are at increased risk of substance use; categorical diagnoses may not fully explain individual variability in substance-related outcomes. This study examined substance use severity in clinically complex adolescents, focusing on the role of primary diagnosis and transdiagnostic dimensions (emotional dysregulation, impulsivity, cyclothymic-hypersensitive traits). Methods: In this cross-sectional observational study, 47 adolescents (aged 14–17) with DSM-5 diagnoses of ADHD or bipolar spectrum disorders were recruited from two Italian child and adolescent mental health services. Substance use severity was assessed using the Q-PAD Substance Abuse scale and the ABQ. Emotional dysregulation, impulsivity, affective temperament, and emotional-behavioral problems were assessed through RIPOST-Y, BIS-11, CHT-Q, and YSR. Correlation studies and group comparisons based on the Q-PAD Substance Abuse scale were performed to explore associations between clinical features and substance use. Results: Substance use severity was elevated in the overall sample and was not significantly associated with primary diagnostic category, overall illness severity, or global functioning. Higher Q-PAD Substance Abuse scores were significantly associated with impulsivity, emotional dysregulation, and hypersensitivity traits. Later initiation of lithium treatment was also associated with greater substance use severity. Conclusions: In this sample, substance use severity was more related to dimensional transdiagnostic vulnerabilities than to categorical diagnosis. Although preliminary and exploratory, these findings support early identification and targeted intervention on emotional dysregulation and impulsivity as potentially modifiable risk factors for adolescent substance use.