Depression is a major public health concern, with a wide range of symptoms, including hopelessness, fatigue, impaired concentration, feelings of inadequacy, as well as slowed thought and movement processing (APA 2013).

These symptoms not only impact upon an individuals’ personal life, but can impair social functioning and the ability to work (Hirschfeld 2000, Lerner 2008).

Within the US, depression was related to 27.2 lost workdays per ill worker per year, and a total of $36.6 billion capital lost in the US labour force (Kessler, 2006).

A new Cochrane systematic review and meta-analysis aims to evaluate the effectiveness of the current interventions available for reducing workplace disability in depressive disorder (Nieuwenhuijsen et al, 2014).

Methods

The authors searched the following databases between January 2006 and January 2014: CENTRAL, MEDLINE, psychINFO, EMBASE, and CINAHL. Studies were included if they were:

• Randomised controlled trials (RCT) or cluster RCTs
• Participants were adults (17+)
• Participants were from occupational health, primary care, or outpatient care settings
• Depressive criteria met diagnostic criteria, was assessed by a self-reported symptom scale, or by a clinical rated instrument.

Studies were excluded if participants had a primary diagnosis of a psychiatric disorder other than depressive disorder including bipolar depression and depression with psychotic tendencies.

The authors included both workplace (modify the task or hours) and clinical (antidepressant, psychological, or exercise) interventions, and the primary outcome examined was the number of illness-related absences from work during follow up (Nieuwenhuijsen et al, 2014).

Results

The original search yielded a total of 11,776 studies, and resulted in a full text assessment of 73 studies. 50 studies were excluded at the full-text stage- resulting in 1 study included in qualitative synthesis only, and 22 studies included within the meta-analysis.

Overall there were 20 RCTs and 3 Cluster RCTs, totalling 6,278 participants ranging from 20-200 participants between studies. 7 studies recruited from primary care settings, 10 from outpatient, 2 from occupational health, 1 from a managed care setting, and 1 was conducted in a community mental health centre (Nieuwenhuijsen et al, 2014).

Work directed interventions

5 work-directed interventions were identified:

• There was moderate evidence that a work-directed intervention plus a clinical intervention reduced sick days when compared to clinical intervention alone or a work intervention alone
• There was low evidence that an occupational therapy and return to work program was beneficial over occupational care as usual

Antidepressants

6 studies investigated and compared the effectiveness of different antidepressant use, including SSRI, SNRI, TCA, MAO, and placebo:

• There was no difference between SSRIs and TCAs in reducing sickness absence, while another study found low quality evidence that either TCAs or MAOs reduced absences over placebo
• Overall, the results of this category were inconsistent

Psychological therapies

• There was moderate evidence of online or telephone CBT against occupational care as usual for reduction of absences
• Two studies displayed no evidence that community health nurse interventions helped any more than care-as-usual

Psychological therapies combined with antidepressants

• Two studies found that enhanced primary care did not decrease sick days over 4-12 months, and another longer term study found similar results
• However, there was high quality evidence that a telephone outreach management program can be effective in reducing sick leave compared to care-as-usual

Exercise

• There was low quality evidence that exercise was more effective than relaxing in sickness absence reduction
• However, there was moderate evidence that aerobic exercise was not more effective than relation or stretching

Discussion

This review evaluated a number of RCTs investigating work or clinical interventions. However, in each category, there was a large amount of variation between the studies and very few studies per category making comparisons difficult.

There was moderate evidence that work-directed interventions combined with a clinical intervention reduced sick leave, and that primary or occupational care combined with CBT also reduced absences. Additionally, there was evidence that a telephone outreach management program with medication reduced absences from work compared to care as usual.

This suggests the need for more research on work-directed interventions to be paired with clinical care, as they have the potential to reduce illness-related absences, but there are currently limited studies evaluating these interventions (Nieuwenhuijsen et al, 2014).

Links

Nieuwenhuijsen K, Faber B, Verbeek JH, Neumeyer-Gromen A, Hees HL, Verhoeven AC, van der Feltz-Cornelis CM, Bültmann U. Interventions to improve return to work in depressed people. Cochrane Database of Systematic Reviews 2014, Issue 12. Art. No.: CD006237. DOI: 10.1002/14651858.CD006237.pub3.

American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. Arlington, VA: American Psychiatric Association, 2013.

Hirschfeld RM, Montgomery SA, Keller MB, Kasper S, Schatzberg AF, Moller HJ, et al. Social functioning in depression: a review. Journal of Clinical Psychiatry 2000; 61 (4):268–75. [PubMed abstract]

Lerner D, Henke RM. What does research tell us about depression, job performance, and work productivity? (PDF) Journal of Occupational and Environmental Medicine 2008; 50(4):401–10.

Kessler RC, Akiskal HS, Ames M, Birnbaum H, Greenberg P, Hirschfeld RM, et al. Prevalence and effects of mood disorders on work performance in a nationally representative sample of U.S. workers. American Journal of Psychiatry 2006; 163(9):1561–8.