Workplace burden of Depression magnified by co-morbid anxiety and fatigue

Depression, well known to reduce workplace productivity, causes significantly greater productivity declines when accompanied by common co-occurring conditions such as fatigue, sleep problems or anxiety, according to a large new study presented at the American Psychiatric Association's 160th Annual Meeting in San Diego. The study also showed that co-occurring fatigue or sleep problems significantly increased depression-related healthcare costs.

In the study, which used an integrated database of healthcare claims and surveys of almost 14,000 employees at two large U.S. companies, researchers analyzed data on healthcare spending and presenteeism (i.e., employees' estimates of their own productivity while at work) to assess the impact of depression and other chronic conditions.

At one of the companies, depression in the absence of anxiety or fatigue/sleep disturbance was associated with a 3.5 percent reduction in the presenteeism score, equivalent to seven to eight full-time workdays per year. Depression with anxiety or fatigue/sleep disturbance was associated with larger negative effects (6-8 percent reduction in average presenteeism score), and having depression with both anxiety and fatigue/sleep problems was associated with a 13.2 percent reduction.

Overall, among the ten most prevalent physical and mental conditions measured, depression had the single largest negative effect on work productivity. That effect was magnified when fatigue, sleep problems and anxiety - conditions that often co-occur with depression - were also present. Further, while depression had significant adverse effects on productivity in the absence of other co-morbid conditions, effects of these other conditions in the absence of depression were not as pronounced.

Painful conditions also had large effects. However, when the effect of each condition was examined while controlling for comorbid depression, the independent effect of the condition was diminished.

Employees experiencing depression had average annual costs in excess of both employer sample averages (US$4,132 and US$3,504 compared to US$3,286 and US$2,653, respectively). Employees who reported experiencing fatigue or sleep problems with depression had significantly higher average annual costs than those with depression alone (US$6,665 and US$5,306). (All results noted above statistically significant, p<0.05). Although having anxiety with depression was associated with lower rating of work performance, direct healthcare costs were not significantly different from costs of employees with depression alone.

"While depression itself has a significant economic impact, the negative effect on both workplace productivity and healthcare costs can be considerably increased when employees who are depressed also suffer from other conditions," said Ronald C. Kessler, Ph.D., Professor of Health Care Policy, Harvard Medical School, Boston, Mass. "These findings suggest we should aim to identify and minimize multiple factors associated with depression early to reduce this burden."

Kessler R, White LA, Birnbaum H, et al.
Pathways on Work Productivity.
APA Annual Meeting, 2007 May 21.