Current nosology of addictions limits both clinicians and researchers. The diagnoses are syndromic (based on clusters of symptoms and clinical course rather than etiologically based).132 In addition, diagnoses are categorical, assuming a cutoff between normal and abnormal, although many of the problems associated with addiction are found in people who fall below the disease-associated threshold.133 As discussed, twin studies have detected evidence of etiologic factors shared with other psychiatric diseases28 and linking normal (personality) and abnormal variations (psychopathology).19,32The identification of specific genes and environmental factors altering vulnerability and ability to recover would seem to represent a first step to develop an etiologically based nosology and to individualize treatment. In this reconceptualization of addiction, neuroimaging and neuropsychological measures would be combined with genotype to help define new diagnostic categories encom-passing both premordid vulnerability and addiction-induced neurobiologic change. Such a sea change in addiction diagnosis and management would require the collection of behavioral and genetic measures and their use against a research foundation that is today largely nonexistent. However, one of the first examples of pharmacogenetic prediction of treatment response in the
