Genetic and environmental influences on the stability of psychotic experiences and negative symptoms in adolescence.

Laura Havers,Angelica Ronald,Mark J Taylor

doi:10.1111/jcpp.13045

Laura Havers, Angelica Ronald + Show 1 more

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https://doi.org/10.1111/jcpp.13045

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Abstract

BackgroundPsychotic experiences (PEs) such as paranoia and hallucinations, and negative symptoms (NS) such as anhedonia and flat affect are common in adolescence. Psychotic experiences and negative symptoms (PENS) increase risk for later psychiatric outcomes, particularly when they persist. The extent to which genetic and environmental influences contribute to the stability of PENS in mid‐to‐late adolescence is unknown.MethodsUsing the Specific Psychotic Experiences Questionnaire (SPEQ) twice across ~9 months in adolescence, N = 1,448 twin pairs [M = 16.32 (0.68)] reported experiences of paranoia, hallucinations, cognitive disorganization, grandiosity and anhedonia, and their parents reported on a range of NS. Individuals were split into low‐scoring, decreasing, increasing and persistent groups for each subscale. Frequencies and mean differences in distress, depression traits and emotional problems were investigated across groups. Longitudinal structural equation modelling was used to estimate the aetiological components underlying the stability of PENS.ResultsPhenotypic stability was moderate for all PENS (r = .59–.69). Persistent PENS across 9 months were associated with greater levels of distress (V = 0.15–0.46, for PEs only), depression traits (d = 0.47–1.67, except grandiosity) and emotional problems (d = 0.47–1.47, except grandiosity and anhedonia) at baseline compared to groups with transitory or low levels of PENS. At both ages PENS were heritable and influenced by shared and nonshared environment. Genetic influences contributed 38%–62% and shared environment contributed 13%–33% to the stability of PENS. Nonshared environment contributed 34%–41% (12% for parent‐rated NS). There was strong overlap of genetic and shared environmental influences across time, and lower overlap for nonshared environment. Imperfect stability of PENS was at least partly due to nonshared environmental influences.ConclusionsWhen adolescent PENS persist over time, they are often characterized by more distress, and higher levels of other psychopathology. Both genetic and environmental effects influence stability of PENS.

Highlights

Experiences such as paranoia, hallucinations, anhedonia and behaviours such as flat affect are reported in childhood and adolescence, and in general population as well as clinical samples (McGrath et al, 2015; Peters et al, 2016; Wong, Freeman, & Hughes, 2014)
At the second time point, variance was explained by both stable and new genetic influences (36% and 42% respectively), and stable and new nonshared environmental influences (3% and 19% respectively). While these results demonstrate that the aetiological effects influencing psychosis-related phenotypes are both stable and dynamic, the crosstime sample size was small for a twin study
The persistent group tended to have more distress associated with their Psychotic experiences (PEs), and higher levels of depression traits and emotional problems and other psychopathology at baseline compared to the other groups

Summary

Introduction

Experiences such as paranoia, hallucinations, anhedonia and behaviours such as flat affect are reported in childhood and adolescence, and in general population as well as clinical samples (McGrath et al, 2015; Peters et al, 2016; Wong, Freeman, & Hughes, 2014). Persistent PENS across 9 months were associated with greater levels of distress (V = 0.15– 0.46, for PEs only), depression traits (d = 0.47–1.67, except grandiosity) and emotional problems (d = 0.47–1.47, except grandiosity and anhedonia) at baseline compared to groups with transitory or low levels of PENS. At both ages PENS were heritable and influenced by shared and nonshared environment. Conclusions: When adolescent PENS persist over time, they are often characterized by more distress, and higher levels of other psychopathology Both genetic and environmental effects influence stability of PENS.

Results

Discussion

Conclusion