Background: DSM-IV diagnosis of major depressive disorder includes a requirement that symptoms result in significant clinical distress or impairment. This criterion is difficult to assess and is often overlooked. This study examines the use of the Sheehan Disability Scale as a possible method of assessing impairment, as well as the relationship between functioning and discontinuation of antidepressant medication.
Method: Patients (N = 272) receiving antidepressant therapy due to an episode of major depressive disorder were asked to complete an antidepressant compliance questionnaire. Patients were telephoned monthly while they continued on antidepressant therapy, up to 6 months. During each call, the Sheehan Disability Scale was administered.
Results: Of patients referred to this study, 94.8% met DSM-IV criteria of at least 5 symptoms of major depressive disorder. Most patients had initial scores ranging from 5 to 8 on all 3 Sheehan disability subscales (occupational, social, and family functioning); 72% of patients had at least moderate impairment (scores > or = 4) on all 3 subscales. After 8 weeks of treatment, 42% of patients had scores < 4 on all 3 subscales (recovery); after 24 weeks, 64% of patients had scores < 4 on all 3 subscales. Dropout risk in men was related to improvement in occupational, social, and family functioning, whereas dropout risk in women was related only to improvement in family functioning.
Conclusion: The Sheehan Disability Scale can be valuable in assessing impairment and thus in correctly diagnosing major depressive disorder. We suggest that scores of 4 or more (moderate impairment) on all 3 subscales indicate sufficient impairment for a strict diagnosis of major depressive disorder. Functional symptoms continued to improve for up to 24 weeks on antidepressant therapy, suggesting 6 months or more of therapy is necessary for maximum functional improvement. Premature discontinuation of antidepressant therapy is more likely to occur in women who experience significant improvement in family functioning or men who experience significant improvement in any functional area.