The nonorthogonal nature of risk factors: Implications for research on the causes of maladjustment.

High-risk research on the determinants of psychopathology has attempted to identify markers of vulnerability for specific disorders. This task is made more difficult by the fact that risk factors are correlated in the general population. Correlated risk factors present a challenge that is not amenable to the univariate, main effects models that are typically used by researchers in the field. This paper discusses the sources of correlation among risk factors and considers the implications for high-risk research. The relative advantages and disadvantages of various methodological approaches and data-analytic procedures are examined. It is concluded that the problem of correlated risk factors is best addressed by developing and evaluating more complex models of the trajectories leading to various forms of maladjustment.