Session VIII - General Interest
Sat., 10/12/13 Topics of General Interest, PAPER #90, 12:59 pm OTA 2013
Anxiety and Depression in the Etiology of Chronic Pain: Results from a Two-Year Cohort Study of Trauma Patients
Renan C. Castillo, PhD1; Stephen T. Wegener, PhD2; Sara E. Heins, BA1;
Jennifer A. Haythornthwaite2; Ellen J. MacKenzie, PhD1; Michael J. Bosse, MD3;
the LEAP (Lower Extremity Assessment Project) Study Group;
1Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA;
2Johns Hopkins Medicine, Baltimore, Maryland, USA;
3Carolinas Medical Center, Charlotte, North Carolina, USA
Background/Purpose: Millions of Americans experience chronic pain. While chronic pain can often be linked to prior trauma, the risk factors for persistence following acute pain have just recently begun to receive attention. Numerous studies have shown that both acute and chronic pain increase risk for depression and anxiety, and a causal relationship has been hypothesized. The purpose of this study is to describe a structural model to explain the temporal relationships between pain, anxiety, and depression.
Methods: Patients (N = 545) from a longitudinal study of severe lower extremity trauma were followed at baseline, 3, 6, 12, and 24 months postinjury using a visual analog pain scale and the depression and anxiety scales of the Brief Symptom Inventory. Structural equation modeling (SEM) techniques were used to study temporal relationships between these three sets of longitudinal variables, presented as standardized regression weights (SRW). Multiple imputation techniques were used to account for missing data.
Results: A single structural model that included pain intensity, anxiety, and depression at all four time points yielded model fit measures indicating an excellent fit. Pain had weak effects on depression during the first year postinjury (3-6 months SRW = 0.07, P = 0.05; 6-12 months SRW = 0.06, P = 0.10), but did not predict depression beyond a year. Similarly, pain had weak effects on anxiety during the first year postinjury (3-6 months SRW = 0.05, P = 0.21; 6-12 months SRW = 0.08, P = 0.03). Depression did not predict pain over any of the time periods. In contrast, anxiety predicted pain over all three time periods, and the standardized regression weights for these relationships nearly doubled over this time span (3-6 months SRW = 0.11, P = 0.012; 6-12 months SRW = 0.14, P = 0.0065; 12-24 months SRW = 0.18, P <0.0001). These effects were independent of the effects of each parameter measured at the previous time point (eg, pain at 3 months predicting pain at 6 months).
Conclusion: The results support the hypothesis that in the early phase following trauma, pain elicits anxiety and depression. These effects are smaller, however, than the effect of anxiety on pain over this time period. In the late (or chronic) phase, the effect of anxiety on pain nearly doubles, and is the only causal effect observed. These results provide further evidence that negative mood, specifically anxiety, has an etiological role in the persistence of acute pain.Alphabetical Disclosure Listing
• The FDA has not cleared this drug and/or medical device for the use described in this presentation (i.e., the drug or medical device is being discussed for an “off label” use). ◆FDA information not available at time of printing. Δ OTA Grant.