Patients with chronic pain who also have depression are more likely to be prescribed opioids, but evidence suggests that opioids can increase the risk of developing depression.
To understand this risk, researchers from the Saint Louis University School of Medicine, Missouri, analysed data from more than 100,000 patients who were new opioid users without current depression. They found that the duration, but not dosage, of opioid analgesic use was linked to an increased risk of new-onset depression. The risk increased by as much as 105% in patients who took opioids for more than 90 days compared with those taking them for a maximum of 30 days.
Writing in the Annals of Family Medicine (2016;14:54–62)
, the researchers say that prescribers should not assume that newly reported depression is caused by pain itself and should counsel patients on these risks.
 Scherrer J, Salas J, Copeland L et al. Prescription opioid duration, dose, and increased risk of depression in 3 large patient populations. Annals of Family Medicine 2016;14:54–62. doi: 10.1370/afm.1885