Discriminant value of repetitive behaviors in families with autism spectrum disorder and obsessional compulsive disorder probands.
Parents of kids with autism and parents of kids with OCD show nearly identical repetitive behavior profiles, so treat the behavior, not the diagnosis.
01Research in Context
What this study did
The team asked 81 parents of kids with autism and 79 parents of kids with OCD to fill out two checklists about repetitive habits. They also recruited 80 parents of typical kids to serve as a comparison group.
Using math called discriminant analysis, they looked for patterns that could tell the three groups apart.
What they found
The math correctly placed 81 % of the typical parents into their own group. But it only separated autism-family parents from OCD-family parents about 46 % of the time—little better than a coin flip.
In plain words, the relatives looked more alike than different on repetitive behaviors, no matter which diagnosis their child had.
How this fits with other research
Iversen et al. (2021) pooled almost the kids and found that weaker executive-function skills go hand in hand with more repetitive behaviors in both autism and typical development. Aline’s result lines up: the overlap across families suggests a shared brain-based trait, not two walled-off disorders.
At first glance, Honey et al. (2007) seems to disagree. That study showed repetitive behaviors tied to play and language delays only in kids with autism, not in typical peers. The key difference is age and setting: Emma looked at the diagnosed children themselves, while Aline looked at their parents. The kids show clearer differences; the adults do not.
Smith et al. (2010) adds another piece. They found high autism traits inside an adult OCD clinic sample. Aline extends this idea by showing the trait link runs in families, not just within patients.
Why it matters
If repetitive behaviors sit on one sliding scale from autism to OCD, you can stop hunting for a magic cutoff that says “this is autism only.” Instead, note the behavior’s function: is it blocking learning, causing distress, or just quirky? Use EF probes or brief play samples to decide whether to treat, and borrow strategies from both autism and OCD manuals—like adding visual cues or brief exposure trials—without worrying about the label.
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02At a glance
03Original abstract
Repetitive behaviors (RB) represent a wide spectrum of symptoms ranging from sensory-motor stereotypies to complex cognitive rituals, frequently dichotomized as low- and high-order sub-groups of symptoms. Even though these subgroups are considered as phenomenologically distinct in autism spectrum disorder (ASD) and obsessive-compulsive disorder (OCD), brain imaging and genetic studies suggest that they have common mechanisms and pathways. This discrepancy may be explained by the frequent intellectual disability reported in ASD, which blurs the RB expressivity. Given the high heritability of RB, that is, the diversity of symptoms expressed in the relatives are dependent on those expressed in their probands, we hypothesize that if RB expressed in ASD or OCD are two distinct entities, then the RB expressed in relatives will also reflect these two dimensions. We thus conduct a linear discriminant analysis on RB in both the relatives of probands with ASD and OCD and subjects from the general population (n = 1023). The discriminant analysis results in a classification of 81.1% of the controls (p < 10-4 ), but poorly differentiated the ASD and OCD relatives (≈46%). The stepwise analysis reveals that five symptoms attributed to high-order RB and two related to low-order RB (including hypersensitivity) are the most discriminant. Our results support the idea that the difference of RB patterns in the relatives is mild compared with the distribution of symptoms in controls. Our findings reinforce the evidence of a common biological pattern of RB both in ASD and OCD but with minor differences, specific to each of these two neuro-developmental disorders. LAY SUMMARY: Repetitive behaviors (RB), a key symptom in the classification of both OCD and ASD, are phenomenologically considered as distinct in the two disorders, which is in contrast with brain imaging studies describing a common neural circuit. Intellectual disability, which is frequently associated with ASD, makes RB in ASD more difficult to understand as it affects the expression of the RB symptoms. To avoid this bias, we propose to consider the familial aggregation in ASD and OCD by exploring RB in the first-degree relatives of ASD and OCD. Our results highlight the existence of RB expressed in relatives compared to the general population, with a common pattern of symptoms in relatives of both ASD and OCD but also minor differences, specific to each of these two neuro-developmental disorders.
Autism research : official journal of the International Society for Autism Research, 2021 · doi:10.1002/aur.2570