The first goal of the analyses was to evaluate the effects of familial risk status on the odds that offspring would develop specific psychiatric disorders by young adulthood. Because the offspring varied in age at entry into the study and at their last follow up visit, survival analyses were performed. Appropriate adjustment for varying age at follow up can be made through censoring of data inherent in survival methods (Kaplan-Meier or Cox Regression (Parmar and Machin, 1995). Kaplan-Meier (nonparametric) survival-analyses were used to determine the proportion of offspring in each risk group who had developed a given psychiatric disorder at each age during the observation period (Kaplan and Meier, 1958). Cox Regression analyses were performed to obtain β and the exponent of β using SPSS (Version 17) to estimate the odds associated with variables of interest. (The exponent of β is computationally equivalent to the odds ratio.)
