Other than OCD, an example might be alcohol dependence. Many researchers look at this disorder from 3 perspectives, the agent (alcohol), the host (characteristics of the person drinking) and the environment. There is a fair amount of evidence that all 3 play a role in the sense that the substance has addictive properties, the person brings their own genetics, biology, personality traits and personal stress, and the environment (family, social groups) also ultimately affect the chances of a person becoming an alcoholic.

Could we apply this same model to other disorders to try to sort out the causal factors?