Temporal Associations between Substance Use and Somatic Symptoms in the Daily Lives of People with Fibromyalgia

Abstract

Compared to the general population, a higher prevalence of substance use has been found among people with fibromyalgia (FM), but little is known about factors related to use of psychoactive stimulants and depressants. Somatic symptoms that are common to the condition could relate to the substance use, either in response to symptom occurrence or to prevent symptom onset. To address these unanswered questions, we examined the temporal associations between substance use (alcohol, nicotine, caffeine, and cannabis) and somatic symptoms (pain, mental fatigue, and physical fatigue) in the daily lives of adults with FM. Adults with FM (N=50; mean age=45±SD; 88% female, 86% white) completed ecological momentary assessments of substance use, pain intensity, and physical/mental fatigue via a smartphone app 5X/day for eight days. Linear-mixed effects models showed that use of nicotine and cannabis were positively associated with concurrent mental fatigue (respectively; B=12.08; p=0.003, B=6.93; p=0.02); in contrast caffeine consumption was negatively associated with concurrent mental fatigue B=-4.28; p=0.000. Of the substances examined, only caffeine use showed a significant contemporaneous association with physical fatigue (B= -4.85; p=0.000) and pain (B= -2.79; p=0.003). For temporal effects results, substance use was not related to later fatigue or pain ratings. However, higher level of pain intensity predicted higher odds of later cannabis use (B= 0.027; p<0.001). Findings indicated that only alcohol use showed no concurrent/temporal associations with somatic symptoms in FM. When participants reported caffeine use, they also reported lower mental fatigue, physical fatigue, and pain. Mental fatigue was higher when people reported use of nicotine or cannabis. In terms of symptoms predicting later substance use, only increased pain was related to later cannabis use. These findings may inform individualized interventions for symptom management and/or problems related to use of psychoactive substances. National Institute of Arthritis and Musculoskeletal and Skin Diseases of the NIH (grant K01-AR-064275).