TY - JOUR
T1 - An application of item response mixture modelling to psychosis indicators in two large community samples
AU - Shevlin, M
AU - Adamson, Gary
AU - Vollebergh, Wilma
AU - de Graaf, Ron
AU - van Os, Jim
PY - 2007/10
Y1 - 2007/10
N2 - Objective Previous research has suggested that psychosis is better described as a continuum rather than a dichotomous entity. This study aimed to describe the distribution of positive psychosis-like symptoms in two large community samples using an item response mixture model. Methods An item response mixture model was used to explain the pattern of psychosis-like symptom endorsement. This model incorporated two elements. First, a continuous non-normal latent variable to explain the observed pattern of data. Second, a categorical latent variable to explain the variation in the continuous non-normal latent variable. Results For both samples, representing broadly and narrowly defined psychosis, the best fitting model was a four-class solution. In both cases, the classes differed quantitatively rather than qualitatively. Conclusions The analysis showed that psychosis-like symptoms at the population level could be best explained by four classes that appeared to represent an underlying continuum.
AB - Objective Previous research has suggested that psychosis is better described as a continuum rather than a dichotomous entity. This study aimed to describe the distribution of positive psychosis-like symptoms in two large community samples using an item response mixture model. Methods An item response mixture model was used to explain the pattern of psychosis-like symptom endorsement. This model incorporated two elements. First, a continuous non-normal latent variable to explain the observed pattern of data. Second, a categorical latent variable to explain the variation in the continuous non-normal latent variable. Results For both samples, representing broadly and narrowly defined psychosis, the best fitting model was a four-class solution. In both cases, the classes differed quantitatively rather than qualitatively. Conclusions The analysis showed that psychosis-like symptoms at the population level could be best explained by four classes that appeared to represent an underlying continuum.
U2 - 10.1007/s00127-007-0244-6
DO - 10.1007/s00127-007-0244-6
M3 - Article
SN - 0933-7954
SN - 1433-9285
VL - 42
SP - 771
EP - 779
JO - Social Psychiatry and Psychiatric Epidemiology
JF - Social Psychiatry and Psychiatric Epidemiology
IS - 10
ER -