Background & Objectives : Longitudinal studies are used in many psychiatric researches to evaluate the effectiveness of treatment. The main characteristic of longitudinal studies is repeated measurements of the patients over time. Since observations from the same patient are not independent from each other, especial statistical methods must be used for analyzing the data. Missing data is an indispensable component in longitudinal. In this study, we examined the effect of comprehensive treatment on social-individual performance in patients with the first episode of psychosis.
Methods : The data was from a clinical trial involving patients who were admitted to the clinics of Roozbeh Hospital between 2006_2008. We employed a random effect model for the analysis of longitudinal ordinal responses with non-monotone missingness using the R software version 3.0.2.
Results: The results showed that comprehensive treatment with follow-up at home, age, and family history of the disease had a significant effect on the social-individual performance of the patients. The estimation of the coefficient of age and its standard deviation were 0.05 and 0.03, respectively. The estimation of the coefficient of family history of the disease was -0.82 with a standard deviation of 0.41, and the coefficient of comprehensive treatment with follow-up at home and its standard deviation, were estimated -1.04 and 0.44, respectively.
Conclusion: The model used in this study showed that the comprehensive treatment with follow-up at home was better because individuals under this type of treatment are more likely to have social-individual performance.
