Differences in the Psychopharmacological Trajectories of School-Age Children with Attention-Deficit/Hyperactivity Disorder with and without Intellectual Disability.

Introduction: Attention-deficit/hyperactivity disorder (ADHD) affects 5% - 7% of school-aged children, while intellectual disability (IDD) affects approximately 1% of the general population. Diagnosing and treating ADHD in individuals with IDD is challenging, not only due to communication difficulties but also because of psychiatric comorbidities that may be present. These factors can result in underdiagnosis of ADHD and increased prescribing of other psychotropic medications. The aim of this study was to determine differences in psychopharmacological treatment (number of prescribed psychostimulants, inefficacy, adverse effects) and in the number of comorbidities and other prescribed psychotropic drugs between patients with ADHD, with and without ID.

Methods: In the study, 845 children were included, divided into two groups: 574 with ADHD without ID and 271 with ADHD with ID. Microsoft® Excel® was used to calculate the Student's t-test, and statistical significance was assumed using the standard p-value of < 0.05.

Results: No significant differences were found in the average number of psychostimulants prescribed between groups (p = 0.57). Among those with ADHD without ID, 52.4% switched psychostimulants, while in the group with ADHD and ID, this change occurred in 56.1%. Statistically significant differences were found in the average number of other psychotropic medications prescribed per patient (p < 0.05) and in the number of antipsychotics prescribed (p < 0.05). Although our study showed more antipsychotic prescriptions for patients with ID compared to those without ID, some studies report similar use of antipsychotics between these groups. Additionally, the group with ID presented significantly more comorbidities than the group without ID (p < 0.05). These findings are aligned with the literature, which indicates a higher prevalence of psychiatric comorbidities in samples of patients with ID compared to those without ID (50% vs 18%).

Conclusion: Individuals with ID are diagnosed with more psychiatric comorbidities and are prescribed more psychotropic drugs. Additionally, more adverse effects and inefficacy with psychostimulants in ID populations require careful monitoring after initiation.