Severity of Depression and Magnitude of Productivity Loss

In their study on 771 currently employed depressed patients, Beck et al demonstrated a relation between the severity of depression and work function: with every 1-point increase in PHQ-9 score, patients experience an additional mean productivity loss of 1,65%. This is an important finding from a well done study. However, we have some remarks about the interpretation of the findings. After all, the authors state: ‘Employers may find it beneficial to invest in effective treatments for depressed employees across the continuum of depression severity.’ So, treat depression in order to restore work function. 1. This study is a correlation study. Depression severity and work function have been measured at the same time. Consequently, no statements can be made about the direction of the relation between the variables. Implicitly, the authors acknowledge that depression severity is the cause and productivity loss the consequence. Wouldn’t the reverse be possible too? Patients lose productivity, for example caused by bad circumstances or too much pressure on their job, and consequently become depressed? And wouldn’t then the advice be totally different? In that case employers should invest in working conditions instead of sending workers to physicians. Oversimplified: is the patient the problem or the working environment? 2. The authors state that ‘Fortunately, high-quality depression treatment has been found to reduce symptoms, and to be cost-effective.’ They refer to the study by Wang et al.1 Unfortunately, the conclusions of this study are based on calculations with a hypothetical cohort. We doubt if the conclusions of this referred study justify the statement of Beck et al. Moreover, the effectiveness of antidepressants is not very high, considering primary care trials: for example, from every 100 depressed patients treated with an SSRI about 80-85 will not have any benefit from taking the antidepressant.2 Moreover, trials using active placebo’s show even smaller effects. Finally, in the real world the benefit of the antidepressants will be lower than in the optimized conditions during RCTs.3 3. In this study work function has been measured in relation to depression severity in patients being treated for depression. Many patients experience side effects when taking antidepressants, certainly in the first period, and these were newly treated patients. Side effects might also lead to work loss, however this possibility is not discussed at all. We believe that it would be interesting to look at this correlation too.

References 1. Wang PS, Patrick A, Avorn J et al. The costs and benefits of enhanced depression care to employers. Arch Gen Psychiatry 2006;63:1345-53 2. Arroll B, Elley CR, Fishman T, Goodyear-Smith FA, Kenealy T, Blashki G et al. Antidepressants versus placebo for depression in primary care. Cochrane Database of Systematic Reviews 2009, Issue 3. 3. Lucassen P, van Rijswijk E, van Weel-Baumgarten E, olde Hartman T. Making fewer depression diagnoses: beneficial for patients? Ment Health Fam Med 2008;5:161-5

Competing interests:   None declared