Transition clinic for neurodevelopmental disorders: preliminary findings from an interdisciplinary model for adolescence to adulthood.

Introduction: Neurodevelopmental disorders (NDDs) are childhood-onset conditions that often persist into adulthood and are associated with substantial functional impairment and complex psychiatric comorbidities. However, the transition from child and adolescent to adult mental health services often remains fragmented, contributing to delayed recognition and unmet clinical needs. This study aimed to describe an interdisciplinary transition clinic model for individuals with NDDs and to present preliminary findings regarding diagnostic outcomes and clinical characteristics. Methods: This study was conducted in a tertiary-care transition clinic jointly operated by consultant child and adolescent psychiatrists and adult psychiatrists, with psychiatry residents participating as observers. All patients were also evaluated by a consultant neurologist as part of the interdisciplinary assessment process. The clinic followed a three-stage model consisting of referral and pre-assessment, interdisciplinary diagnostic evaluation, and integrated treatment and follow-up. Adolescents and young adults aged 15-21 years with suspected or established NDDs underwent psychiatric, neurological, and when clinically indicated, genetic evaluations. Descriptive analyses were performed for diagnostic distributions, newly identified disorders, and psychotropic medication use. Results: A total of 68 participants were included (mean age = 17.90 ± 1.90 years; 54.4% male). The median number of diagnoses increased from 1 (range: 0-4) before the transition clinic assessment to 3 (range: 1-11) after evaluation. Attention-deficit/hyperactivity disorder was the most frequent NDD (66.2%), while 80% of autism spectrum disorder diagnoses were identified during the transition clinic process. Social (pragmatic) communication disorder, social anxiety disorder, avoidant and borderline personality disorder, and body-focused repetitive behavior disorders were frequently newly identified during transition clinic assessments. Structural MRI findings were observed in 26.7% of scanned participants. Discussion: These findings suggest that interdisciplinary transition clinics may facilitate the identification of previously unrecognized NDDs and psychiatric diagnoses during adolescence and emerging adulthood. Integrated psychiatric, neurological, and genetic assessment models may also contribute to continuity of care and psychiatric resident education.