Relation between duration and severity in bereavement-related depression

Prolonged duration is commonly used as an indicator that bereavement-related depression (BRD) is pathological. DSM-IV replaced the traditional 1-year pathology cut-point by a 2-month cut-point. Yet, little evidence exists regarding the validity of these cut-points in indicating increased BRD severity. This study evaluated the validity of the 2-month and 1-year cut-points in differentiating less severe from more severe BRDs in a nationally representative U.S. sample.

National Comorbidity Survey respondents with BRD's (n = 152) lasting 0-8, 9-52 and >52 weeks were evaluated for depression severity using six severity indicators. Cut-point validity was established by discontinuities in severity levels between durations below and above the cut-point.

Bereavement-related depressions of >52-week duration were significantly higher than 9- to 52-week BRDs on four of six severity indicators and on a cumulative overall severity measure of mean number of severity indicators per person, whereas ≤8-week and 9- to 52-week durational categories differed on one severity indicator and not on overall severity. Additional analyses using durations 0-12, 13-26, 27-52 and >52 weeks suggested that alternative <52-week cut-points also lack validity.

The traditional 1-year cut-point validly identifies increasing BRD severity; DSM's 2-month cut-point does not. Duration does not indicate increasing BRD severity before 1 year. Research using the 2-month cut-point may yield misleading results.