Latent Trajectory Analysis of Youth at High Risk of Psychosis Open Access

Fan, Wenyi (2017)

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Psychotic disorders are a group of serious illnesses that affect the mind and cause abnormal thinking and perceptions. These disorders affect over 5% of the population. Among illnesses that affect people ages 15 to 44, schizophrenia is the 8th leading cause of disability worldwide. The first goal of this analysis was to conduct a latent class analysis(LCA) on the longitudinal trajectories of clinical characteristics of youths at Clinical High-Risk(CHR) of psychosis. A second purpose of this study was to examine whether there was an association between two-year clinical outcome and empirically derived CHR subgroups. In this analysis, we used LCA to analyze variables collected as part of the North American Prodrome Longitudinal Study 2 (NAPLS2). The results showed that the two-class model was preferred according to the model selection criteria, AIC, BIC, and ICL-BIC. Based on these two subgroups, a multinomial logistic regression analysis indicated that there was a significant relation between the participants' classifications into latent subgroups and their clinical outcomes.

Table of Contents

Table of Contents

I. Introduction. 1

1. Study topic: The Prodromal Symptoms of Psychosis 1

2. Statistical topic: Latent class analysis 3

II. Method. 5

1. Coding the study variables 5

2. Latent class membership probability. 6

3. Class-specific marker trajectory. 7

4. The missing weight estimation. 7

5. Maximum Likelihood estimation. 9

6. Model selection criteria. 9

7. Multinomial Logistic Regression. 10

8. Proportional Odds Model 11

III. Results. 12

IV. Discussion. 18

1. Discussion of the results 18

2. Future work. 18

V. Reference 20

VI. Appendix. 23

1. Sample and Two-year clinical outcome criteria. 23

2. Proportional odds model results 23

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