PURPOSE: Positive relationships between employment and clinical status have been found in several studies. However, an unequivocal interpretation of these relationships is difficult on the basis of common statistical methods.
METHODS: In this analysis, a structural equation model approach for longitudinal data was applied to identify the direction of statistical relationships between hours worked, clinical status and days in psychiatric hospital in 312 persons with schizophrenia who participated in a multi-centre randomised controlled trial comparing the effectiveness of Individual Placement and Support (IPS) with conventional vocational services in six study settings across Europe. Data were analysed by an autoregressive cross-lagged effects model, an autoregressive cross-lagged model with random intercepts and an autoregressive latent trajectory model.
RESULTS: Comparison of model fit parameters suggested the autoregressive cross-lagged effects model to be the best approach for the given data structure. All models indicated that patients who received an IPS intervention spent more hours in competitive employment and, due to indirect positive effects of employment on clinical status, spent fewer days in psychiatric hospitals than patients who received conventional vocational training.
CONCLUSIONS: Results support the hypothesis that the IPS intervention has positive effects not only on vocational but also on clinical outcomes in patients with schizophrenia.