ANXIETY AND DEPRESSIVE DISorders
are related through
comorbidity and shared
risk factors.1-3 Although
some particular anxiety
disorders may show relatively weak associations
with depressive disorders, clinical4
and epidemiological5,6 studies find that
anxiety and depressive disorders rarely occur
in pure forms. Factor analytic approaches
suggest that these data reflect the
influence of a higher-order “internalizing”
factor.7-10 In the process of revising
DSM-IV,11,12 these findings have stimulated
calls for rethinking of diagnostic
classes13,14 based on data regarding similarities
and differences in risk factors.14