Gender and Psychiatric Symptoms Among Youth with ASD and ADHD

Background: Gender-related differences have been studied in ADHD for many years (e.g., as early as Gaub & Carlson, 1997), but inquiries in autism spectrum disorders (ASD) are relatively new (Bargiele, 2016). An important line of research is investigation into gender differences within and between developmental disabilities. This current study, using a large clinical sample of youth with diagnoses of ASD or ADHD, investigates potential gender-related differences in emotional and behavioral symptoms.

Objectives: To examine potential gender and diagnosis driven differences on the Child Behavior Checklist (CBCL).

Methods: 945 parents of youth with developmental disability diagnoses (440 with ASD and 505 with ASD) reported on their child’s emotional and behavioral functioning using the CBCL. Youth age 6-18 with IQ > 50 were included in the analyses. Altogether there were 690 males and 255 females in the study. The diagnostic groups did not differ in age or IQ. A mixed-model ANOVA was used to investigate internalizing and externalizing symptoms (CBCL t-scores) across gender and diagnostic group, with post-hoc analyses following.

Results: The ANOVA revealed a main effect for diagnosis group (F(1,941)=8.238, p=.004), with ASD children exhibiting overall higher symptoms then ADHD children. Further, an interaction was identified between CBCL domain and diagnosis group (F(1,941)=5.587,p=.020), as the ASD children exhibit greater internalizing problems then ADHD children (post-hoc T-test: t(943)=4.455, p<.001), but similar levels of externalizing problems (post-hoc T-test: t(943)=0.559, p=ns. Additionally, this interaction was further driven by gender (ANOVA 3-way interaction F(1,941)=4.066, p=.040), with ASD girls being higher than ASD boys on externalizing problems specifically (post-hoc T-test: t(438)=-1.984, p=.04), but no differences between ASD boys and girls on internalizing problems, nor differences between ADHD boys and ADHD girls on internalizing or externalizing problems (p-values all = ns).

Conclusions: In a large sample of youth clinically diagnosed with ASD or ADHD, differences were observed with the parents of ASD children reporting higher overall symptoms then parents of ADHD children. This was primarily caused by higher levels of reported internalizing problems, rather then externalizing problems. However, within diagnostic groups, gender differences were noticed in the ASD children, but not the ADHD children, specifically for externalizing problems. It is important to note that these findings are based on standardized scores that have been normed according to both age and gender, suggesting that while ADHD children follow these norms more closely, the ASD children may exhibit discrepancies from these norms. These findings are in line with a growing literature of notable gender-related differences and risks within developmental disabilities, particularly ASD. It is also possible that the findings of this study might be driven by the fact that ASD girls who get referred for evaluations have increased overt symptoms. Studies in both ADHD and ASD have identified under-referral of girls for diagnostic evaluations. Finally, the finding of increased internalizing symptoms in ASD as compared to ADHD, without any effect of gender, is notable for potentially increased anxiety and depression specific to the autistic condition beyond developmental disability status.