Background. In unselected samples, the diagnosis of major
depression (MD) is not highly reliable.
It is not known if occasion-specific influences on reliability index
familial risk factors for MD, or
how reliability is associated with risk for co-morbid anxiety disorders.Methods. An unselected sample of 847 female twin pairs
was interviewed twice, 5 years apart, about
their lifetime history (LTH) of MD, generalized anxiety disorder (GAD)
and panic disorder (PD).
Familial influences on reliability were examined using structural equation
models. Logistic
regression was used to identify clinical features that predict
reliable diagnosis. Co-morbidity was characterized using the continuation
ratio test.Results. The reliability of a LTH of MD over 5 years
was fair (κ=0·43). There was no evidence for
occasion-specific familial influences on reliability, and heritability
of reliably diagnosed MD was
estimated at 66%. Subjects with unreliably diagnosed MD reported fewer
symptoms and, if
diagnosed with MD only at the first interview, less impairment and
help seeking, or, if diagnosed
with MD only at the second interview, fewer episodes and a longer
illness. A history of co-morbid
GAD or PD is more prevalent among subjects with reliably diagnosed MD.Conclusions. A diagnosis of MD based on a single
psychiatric interview incorporates a substantial
amount of measurement error but there is no evidence that transient influences
on recall and
diagnosis index familial risk for MD. Quantitative indices of risk for
MD based on multiple
interviews should reflect both the characteristics of MD and the temporal
order of positive
diagnoses.
Altered Intrinsic Functional Brain Architecture in Children at Familial Risk of Major Depression
