The association between chronic pain and depression has long been recognized—as many as 75% to 80% of patients with chronic pain also suffer from depression. Although it is commonly thought that depression is secondary to pain, in fact, pain is one of the most common presenting symptoms of clinical depression.
It is also well known that opioids are central nervous system depressants, and while unlikely to cause depression on their own, they can precipitate depression in those who are already prone to it and exacerbate it in those already experiencing it.
Previous studies have reported that patients with chronic pain and depression are more likely to receive opioids than those who aren’t depressed, and use them for longer periods. A new study examined whether opioid dose is correlated with level of depression in patients with chronic low back pain.1
The study followed 355 patients over a 2-year period, obtaining data on levels of pain and depression, amount of opioid use, and function as measured by the health-related quality-of-life questionnaire.
Daily morphine-equivalent doses of opioids greater than 50 mg were associated with a significantly increased risk of depression; this correlation remained intact even after pain severity was taken into account. Furthermore, worsening depression was associated with an escalated dose of opioids. The authors of the study interpreted these results as an indication that treatment of depression in patients with chronic pain may result in reduction of opioid doses.
The results of this study are not unexpected. As previously mentioned, opioids are central nervous system depressants, so it makes sense that there may be a corresponding risk of precipitating or exacerbating depression as opioid dosage increases.
The linkage between opioids and depression is obviously a concern in any age group. There are certain patients, however, for whom there are special concerns about increasing the risk of depression because of circumstances that might make its treatment more difficult. One of these groups is women who may become pregnant during their use of opioids.
A new study from the CDC indicates that opioids are being overprescribed for women of reproductive age (ages 15 to 44 years).2
The study used databases from 2008 to 2012 and found that 39% of women in this age group who were covered by Medicaid and 28% of those covered by private insurers filled at least one opioid prescription each year during this period.2
Considering that this is an age group that one would expect to be in relatively good health and therefore not suffer many conditions that would cause pain requiring an opioid, these results add to existing concerns that these drugs are being overprescribed. Furthermore, the fact that the women received the prescriptions during each of the years surveyed indicates that this wasn’t being done simply for a one-time or transient problem.
What was of special concern to the authors was the possibility of pregnancy while the opioids were being used.2
Opioids and Expecting
Two studies published in 2014 also raised concerns about the overprescription of opioids for pregnant women. The first study found that in over 14% of women with private insurance, an opioid was prescribed at some point during pregnancy.3 The second study found that almost 22% of those with Medicaid received such a prescription.4
Neither study looked specifically at problems associated with opioid use during pregnancy but there is a recognized association between opioid use and congenital defects, including neural tube and heart defects, as well as neonatal abstinence syndrome, in which the infant experiences withdrawal symptoms because of the mother’s opioid use.
What we know very little about—and these studies do not address—is whether opioids may be associated with depression both during pregnancy and in the postpartum period.
An estimated 10% to 20% of women experience major depression during pregnancy with similar estimates for postpartum depression. There is ongoing debate about weighing the benefits of medication management of depression during pregnancy against possible risk to the fetus from antidepressants. Obviously health care professionals would want to do whatever is possible to avoid precipitating or exacerbating depression that might increase the need for antidepressant treatment. If opioids may pose such a risk, this is an additional reason why we should be more judicious in their use.
Although the issue of direct damage to the child isn’t relevant to the management of postpartum depression, we want to avoid any intervention that might precipitate this disorder as it can interfere with care of the child as well as cause suffering for the new mother and the rest of the family.
There is a need for studies that determine the relationship between opioid use and dosage and depression during pregnancy. However, in prescribing opioids for women who may become pregnant, physicians need to be aware of the drugs’ depressant effects and that there may be a connection between the drugs and mood.
Obviously we shouldn't deny opioid analgesics to those who need them. Before they are prescribed, however, we need to weigh many factors including the consequences of their use should a woman become pregnant while taking them.
1. Scherrer JF, Salas J, Lustman PJ, et al. Change in opioid dose and change in depression in a longitudinal primary care patient cohort. Pain. 2015;156:348-355.
2. Ailes EC, Dawson AL, Lind JN, et al. Opioid prescription claims among women of reproductive age—United States, 2008-2012. MMWR Morb Mortal Wkly Rep. 2015;64:37-41.
3. Bateman BT, Hernandez-Diaz S, Rathmell JP, et al. Patterns of opioid utilization in pregnancy in a large cohort of commercial insurance beneficiaries in the United States. Anesthesiology. 2014;120:1216-1224.
4. Desai RJ, Hernandez-Diaz S, Bateman BT, Huybrechts KF. Increase in prescription opioid use during pregnancy among Medicaid-enrolled women. Obstet Gynecol. 2014;123:997-1002.