Our results lend support to the concept of availability-proneness, which predicts that the liability to initiate and progress to abuse are a function of both hereditary and environmental influences (42). Moreover, portions of these risks can be explained by availability which influences the risk of initiation as well as progressing to symptoms of abuse. These results raise important considerations such as whether or not reducing availability can lead to a reduction in initiation and subsequent abuse. Indeed, this is the basis for the `War on Drugs'.
