Patients with no history of substance abuse who had severe depression were three times more likely to misuse their opioid medications, according to study results.
“Depressed patients may use opioids to treat stress and insomnia, as well as pain,” study researcher Mark D. Sullivan, MD, PhD, told Healio.com. “This may lead them to overuse their opioids.”
Sullivan, along with Alicia Grattan, MD, of the department of psychiatry and behavioral sciences at the University of Washington School of Medicine, and colleagues interviewed 1,334 patients on chronic opioid therapy for noncancer pain who had no history of substance abuse. The researchers asked participants about self-medicating for symptoms other than pain, self-increasing doses and giving or receiving opioids from others. Depression was assessed using the eight-item Patient Health Questionnaire, and participants were asked to rate their pain on a scale from 0 to 10, in which 0 is “no pain” and 10 is “pain as bad as could be.”
Participants with moderate and severe depression were 1.75 (P=.031) and 2.42 (P=.001) times more likely, respectively, to misuse their opioid medications for nonpain symptoms than were participants who were not depressed, data showed. Participants with mild, moderate and severe depression were 1.93 (P<.001), 2.89 (P<.001) and 3.13 (P<.001) times more likely, respectively, to use more opioids than prescribed, compared with those who were not depressed. There was no statistically significant association between depression and giving or receiving opioids from others. The average pain severity of the participants ranged most frequently from 3 to 5.
Among participants who self-medicated for symptoms other than pain, 36.9% had no depressive symptoms, 40.2% had mild depressive symptoms, 47.2% had moderate depressive symptoms and 51.8% had severe depressive symptoms. Among those who did not adhere to the prescribed dosage, 27.3% had no depressive symptoms, compared with 42.6%, 54.3% and 57.7% of participants who had mild, moderate and severe depressive symptoms, respectively.
The researchers said finding a definitive causal relationship between opioid misuse and depression is difficult with this cross-sectional study, but it is possible that depression promotes opioid misuse and that opioid misuse promotes depression by increasing apathy and lethargy.
“Alternatively, opioids are known to have independent anxiolytic and mood-altering properties that may prompt misuse in depressed patients,” they wrote. “Historically, opioids have been used to treat psychological distress (mania and melancholia), as well as physical pain, and more recently studies have suggested using opioids for treatment-resistant depression and anxiety.”
However, Sullivan and colleagues advised clinicians to be alert to the risk of patients with depressive symptoms using their opioids to relieve those symptoms.
“At this point, it is not clear whether opioids are substituting for, or even disrupting, the appropriate treatment of depression,” they wrote. “Although patients and perhaps clinicians may think that relieving pain with opioid medications will also alleviate symptoms of depression, there is no evidence from controlled trials that opioids are adequate treatment for depression.
Disclosure: The researchers report no relevant financial disclosures.