By eliminating the higher-order neuroticism factor, we examined whether peer-reported neuroticism differed from self-reported neuroticism (Figure 2). We constrained the correlations between neuroticism and internalizing psychopathology, as well as the correlation between neuroticism and substance use, to be equal for self- and peer-reported neuroticism. A Wald test showed that adding these two constraints would degrade the model, χ2 (2)=26.7, p<.0001, indicating that self-reported neuroticism had different associations than peer-reported neuroticism. However, peer-reported neuroticism did share some variance with self-reported neuroticism (r=.42). The higher-order neuroticism factor, indicated by both self- and peer-report, had higher convergent validity than self-reported neuroticism alone with internalizing psychopathology (.98 versus .78). However, discriminant validity coefficients with substance use were similar for high-order neuroticism and self-reported neuroticism (.29 versus .25). In this model, internalizing psychopathology and substance use had a large, significant correlation (r=.45). We also analyzed this model with the weighted sample and obtained similar results (CFI=.97, RMSEA=.02, WRMR=.80).
