The ''paradigm shift'' in the title of this article refers to molecula
r biology. The real challenge to molecular biologists interested in ap
plying their methods to an understanding of psychiatric disorders invo
lves the development of models that account for gene/environment/devel
opment interaction. Because of the existence of homologous animal mode
ls of addictive disorders, as well Its a rich body of clinical observa
tions and clinical and behavioral research, and recent data suggesting
that chronic exposure to addictive drugs results in changes in gene e
xpression in neurons from behaviorally relevant brain regions, addicti
ve disorders offer a serendipitous model (to molecular biologists) tha
t may have relevance to subsequent application in other areas of psych
iatry and psychology.