Psychiatric Comorbidity in Intellectual Developmental Disorders: A Systematic Review

Aims/Background Intellectual developmental disorders (IDD) are characterized by significant limitations in intellectual functioning and adaptive behavior, affecting conceptual, social, and practical skills. They impact 1% of the global population, with mild cases being more common. Major causes include prenatal, perinatal, and postnatal factors, although a clear cause is often not identified. This study aims to evaluate the comorbidity of psychological disorders in individuals diagnosed with IDD. Methods Following the "Preferred Reporting Items for Systematic reviews and Meta-Analyses" (PRISMA) statement, studies from 2014 to 2024 were considered using the databases Web of Science, PsycInfo, and PubMed. Articles focusing on psychopathology in individuals with IDD from birth were selected, excluding studies involving individuals under 16 years old and cases of severe and profound IDD. Results Of the 2895 articles retrieved, 11 were included. These studies showed heterogeneity in comorbidities such as schizophrenia spectrum and other psychotic disorders, mood disorders, anxiety disorders, developmental disorders, personality disorders, substance use disorders, and adjustment and stress reaction disorders. Conclusion Individuals with IDD are more vulnerable to mental health conditions, underscoring the need for comprehensive assessments and multidisciplinary treatments to improve their quality of life and optimize public resources. Future research should develop validated diagnostic tools for IDD and conduct longitudinal studies on their impact on quality of life. It should also explore gender differences and address specific needs in disadvantaged contexts with tailored interventions. Systematic Review Registration PROSPERO (CRD42024529405).