Autistic-like behaviors in toddlers might predict psychotic events in adolescence, a retrospective study has determined.
Speech problems and ritualistic behaviors in 3- and 7-year-olds showed a particularly strong influence, increasing the risk of psychosis in preteens by up to 300%, Rhys Bevan Jones, Ph.D., and colleagues wrote in the March issue of Schizophrenia Research (Schizophr Res. 2012;135:164-9).
In the study, nearly 20% of children with these characteristics at age 7 went on to develop psychotic episodes by age 12.
"The findings of this study suggest that clinicians should ask about psychotic experiences in those with autistic traits," wrote Dr. Jones of Cardiff (Wales) University. "Clinicians should also assess for traits of autism in those who develop psychotic experiences (23% of those with psychotic experiences in adolescence had at least one autistic trait at the age of 3, and 10% had at least one psychotic trait at the age of 7). Clinical care is likely to be enhanced by careful consideration of premorbid and comorbid autistic traits that might be impacting on patient function."
"It is also possible that [autism spectrum disorders] and psychotic disorders represent part of the same disorder that is manifest differently at different stages of development."
The authors examined data from the Avon Longitudinal Study of Parents and Children. The cohort includes 14,541 children who were born from April 1991 to December 1992, and assessed annually. Dr. Jones’s study comprised 6,439 with childhood data on autistic traits and who were interviewed at age 12 for any psychotic episode.
Psychosis was measured with the psychosis-like symptoms interview, which includes 12 core questions about hallucinations, delusions, and experiences of thought interference over the prior 6 months.
At age 3, 14% of the entire group had speech problems, 9% social problems, and 3% ritualistic behaviors. By age 7, many of these had disappeared, leaving 4% with speech problems, 3% with social problems, and 2% with ritualistic behaviors.
At age 12, 744 children (11.5%) had experienced a psychotic episode. Of these, 483 had no autistic traits. One trait was present in 115; 24 had two traits, and three children had all three of the autistic characteristics.
The investigators performed a multivariate analysis that controlled for male gender, family history of mental illness, low IQ, and parental education and income. Another confounder – peer bullying – was examined separately.
Compared to children without toddler-age language concerns, those with speech problems at age 3 were 58% more likely to have a psychotic episode by age 12 – a significant increase. But children who still had speech problems by age 7 were twice as likely to have a psychotic episode (odds ratio, 2.11).
Ritualistic behaviors were also significantly associated with preteen psychosis. Children who showed those behaviors at age 3 were 74% more likely to experience a psychotic episode. Children who still showed ritualistic behavior at age 7 were 300% more likely to have experienced psychosis by age 12 (OR, 3.05). Social difficulties at both ages 3 and 7 did not significantly increase the risk of late psychosis.
The risk of psychosis increased by 33% for every autistic characteristic in a toddler, and by 66% for every characteristic still present at age 7.
Peer victimization also increased the risk of psychosis, the authors noted. Having autistic traits at age 7 increased the risk of bullying by 38%, and bullying at age 8 was associated with a 69% increase in the risk of psychosis.
It’s unclear whether the associations are driven by a common neurobiological underpinning, social stressors associated with autistic characteristics, or a combination of both, the authors wrote.
[Autism spectrum disorders] can lead to a number of potential stressors, including social rejection or isolation, peer victimization, and stresses from academic failure. It is possible that these stresses mediate an increased risk of future psychotic experiences. "It is also possible that [autism spectrum disorders] and psychotic disorders represent part of the same disorder that is manifest differently at different stages of development," they noted.
The study was sponsored by the U.K. Medical Research Council, the Wellcome Trust, and the University of Bristol (England). None of the authors had any financial declarations.