Background: Jumping to conclusions (JTC) is a reasoningand data gathering bias that results in the tendency to require less evidence and make hasty decisions. Preliminarywork on reasoning bias focused primarily on the associationwith delusions, although jumping to conclusions has alsobeen found in non-deluded schizophrenia (SZ) patients. Literature to date has shown JTC as a well-established bias inpsychosis even at First Episode Psychosis (FEP), after remission, and in individuals with at risk mental state. Furthermore, JTC has been found to be associated with pronenessto psychotic-like experiences in the general population. In teresting findings showed also an association with lower cognitive functioning in psychotic patients, and some degree ofstability of JTC over the course of illness. Overall, findingsto date could suggest a shared genetic liability between theoccurrence of JTC and psychosis.The present study aims to investigate in a sample of FEPand healthy controls: 1) environment, cognitive, and clinical factors associated with JTC bias 2) whether the additionof SZ Polygenic Risk Score (PRS) explains any further variance in the model.Methods: We analyzed data on JTC (Beads task 60:40) ina sample of 503 FEP and 959 population controls for whichgenetic information was available, recruited as part as theEU-GEI study across UK, Netherlands, France, Spain, Italyand Brazil. In the first step, logistic regressions have beenperformed to predict JTC respectively in cases and controlsconsidering as covariates: age, gender, level of education,IQ, country, frequency of cannabis use, population density,positive symptoms, and 20 principal components (PCs) forpopulation stratification. In the second step, we estimateda model adding SZ PRS to the aforementioned terms.Results: Individuals coming from Brazil were about 6 timesmore likely to jump to conclusions in case group (OR=6.69;CI 95%=2.23-20.06; p=0.001) and around 5 times amongcontrols (OR=4.76; CI 95%=2.28-9.93; p<0.001). Likewise,age and low IQ were found to be associated with JTC inboth cases (age: OR=1.04; CI 95%=1.02-1.06; p<0.001. IQ:OR=0.98; CI 95%=0.94-0.98; p<0.001) and controls (age:OR=1.04; CI 95%=1.02-1.05; p<0.001. IQ: OR=0.96; CI95%=0.95-0.97; p<0.001), although a small effect size wasobserved. A similar trend was detected regarding the association with increased positive symptoms in cases (OR=1.27;CI 95%=1.02-1.57; p=0.02), whereas controls presentinghigher level of psychotic-like experiences showed about a3-fold risk to jump to conclusions (OR=2.6; CI 95%=1.12-6.02; p=0.02). In addition, being female resulted as significant predictor in cases only (OR=1.87; CI 95%=1.16-3.01;p=0.009).Finally, PRS for schizophrenia seemed not to be associated with jumping to conclusions in both groups, thereforeit does not add any variance explained in the abovementioned model (Cases: R2=0.27; Controls: R2=0.22).Discussion: This study suggests that the occurrence ofjumping to conclusions cannot be explained by schizophrenia genetic underpinnings using polygenic risk score strategy. However, these preliminary results identified interesting environment, cognitive, and clinical factors associatedwith JTC bias.
|Number of pages||1|
|Publication status||Published - 2019|