Parental Perspectives on Psychiatric Comorbidities in 989 Preschoolers with Autism Spectrum Disorder: Findings from an Italian Multi-Centric Study

Background: An increased prevalence of psychiatric comorbidity (PC) in individuals with Autism Spectrum Disorders (ASD) is consistently reported and it is associated with a poorer prognosis and with a great psychological distress in families. While several studies have examined PC in school-aged children, adolescents and adults with ASD, investigations on PC in preschoolers are lacking. The difficulty to find properly and easy-to-use diagnostic tools to detect PC in ASD preschoolers could contribute to the relatively sparse studies in this area.

Objectives: We explore the prevalence and type of PC in a wide sample of ASD preschoolers through the DSM-Oriented Scales (DOS) of the Child Behaviour Checklist (CBCL 1.5-5) and their possible links with the core features of ASD and cognitive functioning. The role of the psychiatric Multi-Comorbidity was also discussed.

Methods: The sample included 989 ASD preschoolers (age-range: 16-75 months; M: 44.0 months; SD: 13.8 months) recruited by three different Italian care centers for children. These children were selected among individuals who received a diagnosis of ASD based on DSM 5 criteria. Included subjects were assessed using ADOS (ADOS-G or ADOS-2) and a standardized cognitive evaluation (LIPS-R, GMDS-ER or WPPSI tests) while their mothers completed the CBCL 1.5-5. The severity of autism was measured through the Calibrated Severity Score based on ADOS Total score and Social Affect (SA) and Restricted Repetitive Behaviors (RRB) sub-scores. The borderline and clinical DSM-Oriented Scales (DOS) scores of CBCL 1.5-5 were used to explore psychiatric comorbidity.

Results: About 37.8% of the sample had at least one PC in addition to ASD; these subjects displayed significantly higher Total score (p=0.02) and Social Affect score (p=0.003) on the ADOS-based calibrated severity scores (CSS), as well as lower (p=<0.0001) performance IQ (pIQ) compared to ASD individuals without PC. As far as the specific DOS, Affective Problems (AP) were detected in 23.4% of the whole sample, ADHD Problems (ADHD) in 17.3%, Anxiety Problems (ANXP) in 16.7%, and Oppositional Problems (OP) in 7.9%. These different comorbidities were isolated in 195 subjects (Mono-Comorbid group: 19.7% of the whole sample), while 179 subjects (18.1% of the whole sample) had two or more types of PC (Multi-Comorbid group). One-way ANOVA revealed that the Multi-Comorbid group had statistically significant lower pIQ and higher Total score and Social Affect score on CSS-ADOS. The 10% of total sample had relevant sleep problems.

Conclusions: This study suggests that in people with ASD, PC occur early in life worsening ASD symptoms and cognitive functioning necessitating the need for their early detection in order to plan tailored interventions. The use of parental questionnaires as screening tools to investigate PC could anticipate the individuation of psychiatric symptoms different from autism, contributing in diminishing the consistent risk for mis- or under-diagnosis PC in young children with “ASD and PC”.