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Higher schizophrenia risk scores tied to early-onset emotional problems

Development of emotional problems in early childhood was linked to higher risk for schizophrenia, study findings published in the American Journal of Psychiatry showed.

However, the findings also suggest that exposure to chronic peer victimization in late childhood affected the later course of emotional problems for those who might otherwise have remained on a more favorable trajectory.

“Schizophrenia risk alleles may contribute to the trajectories of emotional problems from an early age, although this has not been tested directly,” Lucy Riglin, PhD, division of psychological medicine and clinical neurosciences, Cardiff University, and colleagues wrote. “However, genetics alone cannot explain the developmental course of emotional problems. Psychosocial stressors also contribute risk; some are particularly prevalent in childhood.”

In their study, researchers examined how psychiatric risk alleles impact early-onset mental health trajectories and whether these trajectories were later modified by exposure to bullying in late childhood among 3,988 participants of a prospective U.K. population-based cohort.

The investigators estimated developmental trajectories of emotional problems when participants were about 4 to 8 years and about 12 to 17 years of age. Using previous genome-wide association study results from the Psychiatric Genomics Consortium, they indexed psychiatric risk alleles by polygenic risk scores for schizophrenia. They also indexed chronic peer victimization at ages 8.5 and 10.5 years as an environmental exposure.

Analysis revealed that higher schizophrenia polygenic risk scores were linked to a trajectory of early-onset increasing emotional problems (OR = 1.18; 95% CI, 1.02-1.36) compared with a trajectory of low-stable emotional problems in the study population. In addition, later exposure to bullying boosted the risk of transitioning from a trajectory of low-stable emotional problems during childhood to an increasing trajectory during adolescence (OR = 2.59; 95% CI, 1.48-4.53).

“The findings suggest that there are at least two routes into an increasing trajectory of emotional problems during adolescence,” Riglin and colleagues wrote. “The first is via genetically influenced childhood-onset emotional problems, which show strong continuity with adolescent emotional problems, and the second is via exposure to peer victimization, which alters the developmental course of individuals who are initially on a low-risk trajectory to a less favorable trajectory.”

The investigators concluded that further research that examines how genetic risk variants collaborate with environmental risk and protective factors on multiple psychiatric outcomes is necessary. “Rigorous methods are needed to know which environmental risk factors are likely causal,” Riglin and colleagues wrote. – by Savannah Demko

Disclosure: The authors report no relevant financial disclosures.