Prescription Opioid Use Increases Risks for Mood and Anxiety Disorders

Many observational studies have linked prescription opioid use with depression and anxiety, but clinicians, who often focus on the hypothesis that depression and anxiety increase use of these medications, are less convinced that prescription opioids may themselves cause depression. To clarify issues of cause and effect in a design closely resembling a randomized, controlled trial, researchers conducted a Mendelian randomization study in 737,473 patients of European ancestry from two genome-wide association studies. This approach enabled the researchers to use randomly distributed genetic proxies of mood and anxiety disorders, the use of opioids and nonopioid analgesics, and the presence of chronic pain — and link them to clinical constructs…