Somatic symptom disorder (SSD) is defined as having one or more chronic somatic symptoms that are distressing or disruptive of daily life, as indicated by disproportionate and dysfunctional cognitive, emotional, and behavioral responses. For example, someone with SSD may present with chronic pain, bowel disruptions, or fatigue that is accompanied by anxiety, catastrophic thinking, and behavioral avoidance. The prevalence of SSD is 5 to 7% in the general population (1) and up to 17% in primary care (2). SSD tends to be chronic—up to 90% of patients have symptoms beyond 5 years (3)—and disruptive—the somatic symptoms in people with SSD are associated with psychiatric comorbidity and functional disability such as work impairment or early retirement (4).

One promising treatment for SSD is Emotional Awareness and Expression Therapy (EAET) (5). EAET includes psychoeducation about the central nervous system control of pain and other somatic symptoms, exploration of links between somatic symptoms and unresolved trauma, emotional processing of trauma and conflict, reattribution of somatic symptoms to emotional and brain-based processes, the development of a self-soothing capacity using self-compassion, and encouragement to improve adaptive interpersonal communication. EAET has been tested in randomized controlled trials (RCTs) for people with fibromyalgia (6), irritable bowel syndrome (7), urogenital pain (8), medically unexplained symptoms (9), and musculoskeletal pain (10, 11) and found to be superior to treatment as usual, education controls, and even cognitive behavioral therapy (CBT) (6, 10, 11). In our original RCT, which forms the basis for this follow-up study, an Internet-delivered version of EAET (I-EAET) was superior to a waitlist control in reducing somatic symptoms and pain intensity at post-treatment (small to medium effect size). It also showed superiority for somatic symptoms at the 4-month follow-up, response rates for somatic symptoms at follow-up, and also for depression and anxiety at post-treatment, but not at follow-up. (12). In other clinical trials of EAET, treatment effects have been maintained at short-term follow-up assessments, ranging from 2 to 6 months, but the effects of EAET in any modality after 6 months have not been studied. The purpose of the current secondary analyses was to examine whether the effects of I-EAET at post-treatment of our earlier trial were maintained at 12-month follow-up (12). Because the waitlist condition was offered I-EAET after the 4-month follow-up, the current analyses are within the I-EAET condition only and do not include a control condition.

This is the first study to assess whether somatic symptom reduction at the end of EAET was maintained at 12-month follow-up. The significant post-treatment reductions in somatic symptoms for our participants who received I-EAET were largely maintained 12 months later, with a medium effect size, and the percentage of responders (50% or more reduction in somatic symptoms) was also maintained. The small trend toward increased somatic symptoms between post-treatment and 12-month follow-up was non-significant. The effect on pain severity at 12-month follow-up, however, was no longer significant. On secondary measures, treatment effects were originally not significant at post-treatment, and the 12-month follow-up reflected a return of anxiety and depression. The average levels of depression and anxiety at pre-treatment were, however, only in the mild range, and post-traumatic symptoms were in the subclinical range; these low levels on these measures likely limited improvement.

These results provide preliminary evidence that I-EAET has positive effects 12 months after treatment, at least on reducing somatic symptoms. One might compare these results with those of internet-cognitive behavioral therapy (I-CBT) for similar populations. The effects of I-CBT on pain, compared to controls at post-treatment, are small (22), and the few studies of I-CBT that have 12-month follow-ups have inconsistent results—two studies showed maintained benefits within-condition (23, 24), the third study had a small effect size within-group but not compared to the control condition (25). There is evidence for deterioration over time for people with chronic pain who are untreated (3), whereas the current study found that the positive effect of I-EAET on somatic symptoms was largely maintained. However, we still know too little about what works for people with somatic symptoms in the long-term, and I-EAET and I-CBT have never been directly compared in a trial.

This study has several limitations. Most importantly, these analyses at 12-month follow-up with only within-condition were not compared to a control condition because the original waitlist control participants were offered I-EAET 4 months post-treatment. This lack of a control group precludes concluding that the treatment itself led to the maintenance of improvements. We also do not know what other treatments participants might have obtained over the follow-up period, although the availability of effective treatments for SSD is limited. Moreover, it remains unclear whether the effects of I-EAET observed at the 12-month follow-up are generalizable to other forms of EAET, such as face-to-face individual therapy or group formats. Further, the small sample size limits the statistical power of the study to detect significant effects. Future studies should include control conditions and direct comparisons to other active treatments (e.g., internet-CBT) and have larger samples.

In conclusion, this study provides preliminary evidence that I-EAET has positive effects on somatic symptoms (although not other measures) for people with SSD at 12-month follow-up.