Consistent with our findings, an earlier study using a clinical sample found that both a high symptom count and treatment seeking predicted AD diagnoses (Culverhouse et al., 2005). In general, reliability for psychiatric disorders is higher in clinical samples, explaining why reliability was higher among the subjects who had been in treatment for their AD. Higher reliability found in clinical samples may arise because more severe disorders are more easily recollected. Reliably diagnosed LTH of major depression has earlier been found to be predicted by disease severeness, treatment seeking (Foley et al., 1998; Kendler et al., 1993, 2001), and duration of episode (Kendler et al., 2001). Given that persons who report LTH-AD consistently on different occasions are more likely to be true cases, the covariates found are of importance to both clinical practice and clinical studies when ascertaining the diagnostic status of patients and subjects.
