Figure 1A-F.

Trajectories of infant behaviors among the TD, ADHD, and ASD Classes from 12-36 months of age. Error bars represent 95% Confidence Intervals. (A) Mullen Scales of Early Learning Verbal raw scores. The 3 groups significantly differed by 18 months which continued through 36 months of age. The ASD Class exhibited the lowest scores, the TD class had the highest scores, and the ADHD Class showed intermediate scores. (B) Coded frequency of inattentive behavior. The ASD and ADHD Classes exhibited significantly higher levels compared to the TD Class at 24 and 36 months but did not differ themselves; the ASD Class also demonstrated significantly higher levels than the ADHD Class at 36 months. (C) Coded frequency of out-of-seat behavior. The ASD Class exhibited significantly higher levels compared to the TD Class at 12 and 36 months of age. The ADHD Class also demonstrated significantly higher levels than the TD Class at 36 months of age and did not differ from the ASD Class. (D) Coded frequency of grabbing behavior. The ADHD Class demonstrated significantly higher levels compared to the TD Class from 18-36 months of age. The ASD Class exhibited significantly higher levels than the TD Class at 36 months of age only. (E) Examiner-rated social engagement. The ASD Class exhibited significantly lower scores compared to both other groups from 12-36 months of age. At 18 and 24 months, the ADHD Class also had significantly lower scores than the TD Class, resolving by 36 months. (F) Coded frequency of negative affect. The ASD Class demonstrated significantly higher levels than the TD Class at 12, 24, and 36 months of age but did not differ from the ADHD Class, which also did not differ from the TD Class.