In a recent cohort study published in The Lancet Regional Health – Europe, Researchers from Sweden and Finland conducted a population-based study to investigate the possible association between psychiatric disorders in parents and the risk of offspring developing autism spectrum disorder (ASD).
They found that the highest risk of offspring ASD was observed in cases where both parents had psychiatric disorders, with affected mothers having a higher risk compared to affected fathers alone.
Study: Association between parental psychiatric disorders and risk of offspring autism spectrum disorder: a population-based cohort study in Sweden and Finland. Image credit: Prostock-studio/Shutterstock.com
Record
Worldwide, more than 16% of adults have ASD. The condition is influenced by both hereditary and non-hereditary factors, with parental psychiatric disorders being a significant risk. However, there are no large population studies comparing maternal and paternal psychiatric disorders and their combined effect on offspring ASD.
The complex genetic architecture of psychiatric disorders, with multiple alleles at different loci, may contribute to higher risk. Current evidence on this association is fragmented and hampered by inconsistent results, methodological limitations, and potential confounders.
Therefore, using data from Swedish and Finnish national registries, the researchers in the present study performed a comprehensive analysis. They examined the potential relationship between parental psychiatric disorders and offspring ASD, while accounting for parental sex, comorbidities, and specific psychiatric disorders.
About the study
The study included children born in Sweden (1997–2016) to Nordic parents (Sweden, Denmark, Finland, Iceland or Norway). The data comes from the Swedish Medical Birth Register, the Swedish Multigeneration Register and the Total Population Register. The study was repeated using data from children born to Nordic parents in Finland during the same period.
A total of 2,505,842 children (Sweden n = 1,488,920, Finland n = 1,016,922) were included and followed for a mean of 11 years. Psychiatric disorder diagnoses were obtained from the Swedish National Patient Register and the Finnish Health Care Register using the International Classification of Diseases (ICD) system.
In both Sweden and Finland, regular medical check-ups and developmental assessments are standard procedures for infants and preschool children. Children showing signs of ASD are referred to child psychiatry or neurology specialists for detailed evaluation, following established protocols for diagnosis.
In addition, data on birth year, offspring sex, maternal/paternal age, gestational age, maternal body mass index, maternal smoking during pregnancy, parental income were collected for additional analyses. and education.
Statistical analysis included the use of Cox proportional hazards models, adjusted hazard ratios (aHRs), inverse Kaplan–Meier curves, and evaluations of interaction terms, with robust standard errors and adjustment for offspring year of birth.
Results and discussion
Of the total children included, 33,612 were found to have been diagnosed with ASD. In Sweden, the prevalence was 1.65% in children without a parental psychiatric diagnosis, rising to 2.67% when both parents were affected.
Prenatal psychiatric diagnoses were found in only 4.94% of fathers, 8.24% of mothers only, and 1.63% of both parents. Affected parents were younger, less educated, had lower income, and their offspring were more likely to be preterm and diagnosed with autism earlier.
Psychiatric disorders, either in fathers only (aHR = 1.59), mothers only (aHR = 1.95), or both parents (aHR = 2.34), were associated with increased risk of ASD in offspring, compared with parents without diagnosed psychiatric disorders.
In addition, the presence of comorbid psychiatric disorders in a parent further increased the risk of ASD in the offspring. Similarly, in Finland, offspring ASD risk was found to be highest in cases of psychiatric disorders in both parents (aHR = 3.61), followed by those in mothers only (aHR = 2.12) or fathers only (aHR = 1.63). compared to parents without psychiatric disorders.
Offspring showed significantly higher risk of ASD in all categories of parental psychiatric disorders, with maternal diagnoses associated with higher risk, particularly in neurodevelopmental disorders, mood disorders, neurotic/behavioral disorders, and psychotropic substance use disorders. However, schizophrenia and non-mood psychotic disorders in either parent were found to equally increase the offspring’s risk of ASD.
The study is strengthened by the large-scale birth cohort with long-term follow-up, clinically ascertained psychiatric diagnoses, robust adjustment for confounders, and successful replication in the two countries.
However, the study shows limited statistical precision for specific parental psychiatric disorders, inability to distinguish children raised by nonbiological parents, lack of adjustment for other confounding factors by parents, and absence of data on psychiatric disorders diagnosed at primary care visits. potentially biased towards capturing severe cases.
conclusion
In conclusion, the study found that 20% of children with ASD had at least one parent with psychiatric disorders.
The highest risk of ASD was seen when both parents were affected, followed by cases with only the mother or father affected.
The risk increased with the number of co-occurring disorders. All parental psychiatric conditions were associated with an increased risk of ASD. The findings highlight the importance of assessing various parental psychiatric conditions to identify high-risk children for early interventions and improved outcomes.
