Persistent physical symptoms (PPS) are common, disabling, and associated with high health care use, yet effective and scalable psychological treatments remain limited. Internet-administrated self-help programs may improve access to care. Asynchronous Internet-administered Emotional Awareness and Expression Therapy (I-EAET) with therapist guidance has been shown to reduce somatic symptoms in PPS, but the added value of the of therapist is unclear. Therefore, adults with PPS (N = 154) were randomized to guided (n = 76) or unguided (n = 78) I-EAET. Both formats comprised 10 self-help modules over 10 weeks, focusing on increasing emotional awareness, addressing unresolved conflicts, and fostering adaptive expression of avoided feelings. Guided participants received weekly written therapist feedback, whereas unguided participants had only technical support. Somatic symptom severity (PHQ-15) was assessed weekly and analyzed using linear mixed-effects models. Results showed that both groups improved significantly over time, but the group × time interaction was not significant, indicating no clear advantage of therapist guidance. However, at post-treatment, guided I-EAET was associated with a small effect size benefit in PHQ-15 scores (d = -0.21) and a higher proportion of responders (47.2% vs. 29.6%) than unguided I-EAET. Secondary outcomes (PHQ-9, GAD-7, PCL-5, DERS-16) also showed small, mostly non-significant differences favoring guidance. These small group differences were attenuated at 10-week follow-up. Taken together these findings indicate that guided and unguided I-EAET yield largely comparable outcomes for persistent physical symptoms. As the study was not powered to detect small between-group effects, these findings should be interpreted cautiously and require confirmation in adequately powered trials.

OBJECTIVE:Difficulties in emotional processing are implicated in the development and maintenance of Somatic Symptom Disorder (SSD) and may represent a target for therapeutic change. This study examined whether session-level emotional processing, operationalized as "rise in complex feelings", predicts subsequent reductions in somatic symptoms during online Intensive Short-Term Dynamic Psychotherapy (ISTDP) for treatment-resistant SSD. METHODS:Twenty-five participants with moderate to severe SSD and non-response across two prior intervention phases received up to 16 sessions of online ISTDP (M = 14.1) delivered by 17 therapists. After each session, therapists rated rise in complex feelings (0-6), reflecting emotional processing within the therapeutic relationship. Somatic symptom severity was assessed weekly using the Patient Health Questionnaire-15 (PHQ-15). Lagged multilevel models tested whether rise predicted the subsequent PHQ-15 assessment, with person-mean centering isolating within-person effects. A one-sided test evaluated the a priori directional hypothesis. RESULTS:Higher-than-usual rise in complex feelings was associated with lower somatic symptom severity at the subsequent assessment (b = -0.22, 95% CI [-0.43, -0.02], one-sided p = .016, two-sided p = .032). The association was robust across sensitivity analyses, including reverse temporal ordering. Adjustment for patient-rated emotional activation and therapeutic alliance only modestly attenuated the estimate. The association was observed within-person; between-person differences in average rise were unrelated to symptom outcomes (b = -0.03, p = .809). CONCLUSIONS:Session-level emotional processing was associated with subsequent reductions in somatic symptoms in online ISTDP, providing preliminary evidence that emotional processing may represent a session-level marker of symptom change in SSD.

Psychodynamic therapies emphasize the healing potential of emotional awareness and relational presence. In online therapy, the therapist’s presence becomes transformed - mediated by written words and digital distance. This exploratory qualitative study examined how participants with Somatic Symptom Disorder (SSD) experienced therapist presence versus absence in Internet-based Emotional Awareness and Expression Therapy (I-EAET), an online psychodynamic treatment designed to help patients engage with avoided emotions linked to physical symptoms. Semi-structured interviews were conducted with ten participants who had completed either a guided or unguided version of I-EAET as part of a randomized controlled trial. Data were analysed using reflexive thematic analysis. The participants described that therapist contact was experienced as both supportive and limited: written guidance provided containment, motivation, and validation, but there was an absence of immediacy and emotional resonance. Working without a therapist was described as fostering autonomy and self-reflection, yet often evoked feelings of isolation. Across conditions, participants described a movement between dependence and independence, containment and solitude. Clinical implications include tailoring the level of therapist involvement to patients’ relational needs and emotion-regulation capacities.

INTRODUCTION:Somatic symptom disorder (SSD) is associated with substantial impairment and high healthcare use, particularly among patients with chronic symptoms, psychiatric comorbidity, and poor response to standard interventions. Intensive short-term dynamic psychotherapy (ISTDP) is a promising emotion-focused approach, but evidence in treatment-resistant SSD remains limited. METHODS:In this interrupted time-series study, 25 SSD patients who showed no improvement across two empirically supported online interventions in the preceding project year received up to 16 sessions (M = 14.1) of online ISTDP. Piecewise multilevel modeling compared PHQ-15 trajectories across 60 weeks before and 21 weeks after start of ISTDP. Secondary measures (PHQ-9, GAD-7, PCL-5, DERS-16) were administered pre-, post-, and at 12-week follow-up. RESULTS:PHQ-15 trajectories were stable or slightly worsening during the pretreatment year but declined significantly after ISTDP began, corresponding to a large estimated slope difference (d = 1.08) at the end of the treatment phase. Among completers (n = 22), 59% achieved minimal clinically meaningful improvement (≥3 PHQ-15 points), 27% showed ≥30% reduction, and 14% met recovery criteria. Secondary outcomes showed significant pre-post improvements in depression (d = 0.68) and anxiety (d = 0.42), while trauma symptoms and emotion regulation showed small, non-significant changes (d ≤ 0.30). Gains were largely maintained at 12-week follow-up. Emotional responses to treatment were common, but serious adverse events rare and dropout low. CONCLUSIONS:Online ISTDP appears feasible and effective for SSD patients who do not benefit from lower intensity interventions and may represent a useful next step in stepped-care pathways for complex, treatment-resistant presentations.

SUMMARY The predominant transdiagnostic perspective on persistent physical symptoms (PPS), as described by Felton et al in this journal, is largely shaped by cognitive–behavioural models. This commentary advocates expanding this perspective to include greater focus on a psychodynamic model that addresses interpersonal and emotional processes associated with the development and maintenance of PPS.

ObjectiveWe examined whether the treatment effects from a previous RCT of Internet-delivered Emotional Awareness and Expression Therapy (I-EAET) for somatic symptom disorder were maintained 12 months after treatment.Method12-month assessments of self-reported somatic symptoms, pain severity, and several secondary outcomes were compared with baseline and post-treatment levels within the I-EAET condition only, given that the waitlist control condition had already received treatment. Twenty-eight out of the original 37 participants (76%) in the I-EAET condition provided follow-up data.ResultsThe beneficial effects of I-EAET on somatic symptoms observed at post-treatment were maintained at the 12-month follow-up (d = -0.22, 95% CI: -0.72 to 0.28), as well as for pain intensity (d = -0.02, 95% CI: -0.52 to 0.48). From pre-treatment to 12-month follow-up, there was a medium effect on somatic symptoms (d = 0.74, 95% CI 0.23 to 1.24), and a small, non-significant effect for pain intensity (d = 0.43, 95% CI -0.06 to 0.93). Response rates (at least 50% symptom reduction) at 12-month follow-up were 25% for somatic symptoms, and 12% for pain intensity.ConclusionI-EAET seems to have positive long-term effects for somatic symptom disorder. Larger studies with controls and comparisons to other treatments are needed.

Functional Somatic Disorders (FSD) present a significant challenge in the health-care system, characterized by persistent, distressing physical symptoms without sufficient medical or psychiatric explanations. This conceptual analysis explores the psychodynamic approach to understanding emotional factors influencing FSD, proposing a new psychological specifier. While current diagnostic frameworks, such as DSM-5’s Somatic Symptom Disorder (SSD) and ICD-11’s Bodily Distress Disorder (BDD), incorporate psychological components, they do not fully address emotional dynamics. This paper advocates for integrating emotional factors into diagnostic criteria. The proposed specifier focuses on emotional factors such as unresolved grief, trauma, and unmet needs, which can exacerbate or cause somatic symptoms. Six signs indicative of emotional influence on somatic symptoms are discussed, emphasizing a collaborative investigative approach. Incorporating this specifier could enhance diagnostic accuracy, treatment planning, and patient outcomes by acknowledging the interplay between emotional and physical health.

There is a growing interest in clinical interventions targeting emotion regulation difficulties across mental health conditions. Experiential dynamic therapies (EDTs) are transdiagnostic, affect-focused, short-term psychodynamic therapy models that emphasize in-session emotional processing. This review provides a 10-year update on the efficacy of EDTs for mood, anxiety, personality and somatic symptom disorders in adults and children/adolescents. A comprehensive search identified 57 randomized controlled trials (n = 4330) conducted in Western (k = 38; n = 3178) and non-Western countries (k = 19; n = 1152) between 1978 and 2024. Random-effects meta-analyses on primary outcomes indicated large, significant effects for EDTs compared to inactive controls at post-treatment (Hedge's g = -0.96; k = 41) and follow-up (g = -1.11; k = 20). Compared to active controls, effects were small and non-significant post-treatment (g = -0.17; k = 27) but became significant at follow-up (g = -0.40; k = 19), suggesting a potential modest long-term advantage of EDTs. Despite substantial heterogeneity (I2 > 75%), results remained robust in sensitivity analyses. Moderator analyses revealed few significant findings, indicating relative consistency across diagnostic groups, treatment formats and active comparators. Non-Western and lower quality studies reported larger effects compared to inactive, but not active, controls. While cautious interpretation is warranted due to unexplained heterogeneity, findings support EDTs as efficacious transdiagnostic interventions for emotional disorders, with sustained benefits over time. Future research should prioritize large-scale, methodologically rigorous trials that explore mechanisms of change, optimize treatment delivery and identify moderators of long-term outcomes.

Although case studies support the notion of three anxiety pathways in Intensive Short-Term Dynamic Psychotherapy (ISTDP), empirical research remains scarce, highlighting the need to investigate how somatic symptoms cluster in line with ISTDP’s anxiety pathway theory using validated measures. This study therefore explored the clustering of self-reported somatic symptoms in 550 patients with persistent physical symptoms (PPS) from three previous randomized controlled trials, examining their potential alignment with the theory of unconscious anxiety and its discharge pathways, as proposed in ISTDP. Using the Patient Health Questionnaire-15 (PHQ-15), an exploratory factor analysis identified three symptom clusters—musculoskeletal, gastrointestinal, and cardiopulmonary—that together explained 40.1% of the variance. This three-factor structure, validated through confirmatory factor analysis, partially aligned with ISTDP’s conceptual anxiety pathways, though limitations were noted in capturing cognitive-perceptual disturbances. These findings suggest that self-reported symptom assessment can complement clinician-led methods in identifying anxiety-related symptom clusters, warranting further development of self-report tools within psychodynamic assessment frameworks.

Persistent physical symptoms (PPS), including (primary) pain, can, according to Emotional Awareness and Expression Therapy (EAET), be precipitated, perpetuated, and prolonged by emotional processes related to unresolved trauma and psychosocial conflicts. EAET is a novel, short-term, psychodynamic- and emotion-focused psychological treatment that targets these etiological factors, intending to substantially reduce or eliminate pain and/or somatic symptoms. This article provides an overview of EAET’s theoretical background, core treatment principles, and empirical evidence from randomized controlled trials (RCTs) in alleviating somatic symptoms in people with PPS. Moreover, the potential of EAET and future research directions are discussed. We report a selective literature review synthesizing the foundations and treatment characteristics of EAET and the findings from RCTs investigating EAET since 2017. Grounded in psychodynamic theory, with influences from affective neuroscience and emotion-focused therapy, the core treatment principles are reframing symptom explanations, fostering emotional processing, and facilitating corrective interpersonal experiences. EAET has been implemented in various formats, including individual therapy, group therapy, and internet-administered self-help. Since 2017, seven RCTs have been published, demonstrating efficacy in reducing symptoms, which appears superior to cognitive–behavioral therapy. EAET is particularly effective for treating chronic (primary) pain conditions such as fibromyalgia and musculoskeletal pain. However, further studies are required to evaluate its long-term efficacy, determine patient characteristics associated with positive outcomes, and better understand its most active mechanisms.

OBJECTIVE:This randomized cross-over trial aimed to compare the effects of a one-session emotion-focused intervention, the Life Stress Interview (LSI), with a Basic Assessment of Psychiatric Symptoms (BAS) condition for patients with persistent physical symptoms (PPS). METHODS:One hundred eighty-nine participants (n=189), predominantly middle-aged females with high psychiatric comorbidity and persistent somatic symptoms, were randomly assigned to receive both LSI and BAS in varying order. Symptom change over time and interaction effects were analyzed using linear mixed models. RESULTS:Both conditions led to significant reductions in somatic symptoms (PHQ-15; B =-0.51, 95% CI=-0.76, -0.26) and psychiatric distress over time, but no significant differences between LSI and BAS were observed. However, significant Sequence×Treatment interaction effects indicated that administering LSI first rather than second resulted in a steeper decline in somatic symptoms (PHQ-15: B =0.57, 95% CI=0.15, 1.00) and post-traumatic symptoms (PCL-5: B =1.85, 95% CI=0.05, 3.64), whereas the timing of BAS had little effect on outcome. CONCLUSION:Our finding that the LSI does not yield more symptom reduction in patients with PPS than a comparison diagnostic interview raises questions about the LSI's unique value, although the observed sequence effect suggests that the LSI may enhance symptom improvement when followed by a psychiatric assessment. Moreover, both brief interventions appear to contribute to symptom reduction. A limitation is that prior psychotherapy experience may have reduced the LSI's impact, and emotional processing during interviews was not assessed. Further research should explore how LSI can be integrated with other interventions to meet the diverse needs of patients with PPS.

During the last years, a number of trials on internet-delivered psychodynamic treatment (IPDT) have shown promising results. In this article we discuss whether two important facets of psychodynamic therapy, that of the therapeutic relationship (especially the transference) and that of emotional processing, are applicable and useful in IPDT. We argue that the therapist role in IPDT does not need to be mainly a supportive one. In this article we try to illustrate that working with the transference relationship and facilitating deep emotional processing is possible in IPDT, potentially adding to the effect of solely taking a supportive stance in guiding through the self-help material. We argue that unguided treatments might make less sense when based on psychodynamic theory due to the lack of a therapeutic relationship and conclude by stating that future research on IPDT could use dismantling designs to establish what therapeutic techniques that are associated with change.

Objective: Somatic symptom disorder (SSD) is commonly encountered in health care settings. Cognitivebehavioural treatments have been most extensively studied, but they tend to have small effects of temporary duration. Emotional awareness and expression therapy (EAET) is a newly developed treatment for SSD, targeting emotional processing of trauma and conflict as a mechanism of symptom change. In an earlier uncontrolled study of self-guided, internet-administrated EAET (I-EAET), we found substantial reductions in somatic symptoms, prompting the need for a randomized controlled trial of I-EAET.Methods: We conducted a 2-arm RCT, comparing 10-week I-EAET (n = 37) to a waitlist control (WL; n = 37). Primary outcomes were reductions of somatic symptoms (PHQ-15) and pain intensity (BPI-4) at post-treatment, with a 4-month evaluation of effect duration. We also analysed emotional processing (EPS-25) and depression (PHQ-9) as possible mediators of I-EAET's effects.Results: Compared to controls, I-EAET significantly reduced somatic symptoms at both post-treatment and followup. I-EAET also reduced pain, depression, insomnia, and anxiety at post-treatment, but these effects were not retained at follow-up. As hypothesized, a facet of emotional processing partially mediated the treatment effect on somatic symptoms, even when controlling for depression.Conclusions: Although treatment effects were smaller than in the previous uncontrolled trial, I-EAET is a promising treatment for SSD, with a minority of patients (around 20%) experiencing substantial clinical improvement. The benefits of I-EAET are partially mediated by improved emotional processing. Future research should identify and target patients who respond best to I-EAET and develop tailored treatment to enhance treatment effects. (Preregistered at clinicaltrials.gov: NCT04751825.)

The 25-item Emotional Processing Scale (EPS) can be used with clinical populations, but there is little research on its psychometric properties (factor structure, test–retest reliability, and validity) in individuals with psychiatric symptoms. We administered the EPS-25 to a large sample of people (N = 512) with elevated psychiatric symptoms. We used confirmatory factor analysis to evaluate three a priori models from previous research and then evaluated discriminant and convergent validity against measures of alexithymia (Toronto Alexithymia Scale-20), depressive symptoms (Patient Health Questionaire-9), and anxiety symptoms (Generalized Anxiety Disorder-7). None of the a priori models achieved acceptable fit, and subsequent exploratory factor analysis did not yield a clear factor solution for the 25 items. A 5-factor model did, however, achieve acceptable fit when we retained only 15 items, and this solution was replicated in a validation sample. Convergent and discriminant validity for this revised version, the EPS-15, was r = − 0.19 to 0.46 vs. TAS-20, r = 0.07− 0.25 vs. PHQ-9, and r = 0.29− 0.57 vs. GAD-7. Test–retest reliability was acceptable (ICC = 0.73). This study strengthens the case for the reliability and validity of the 5-factor structure of the EPS but suggest that only 15 items should be retained. Future studies should further examine the reliability and validity of the EPS-15.

What has been included under the umbrella term “Functional somatic syndromes” (FSS) has varied over the years. Diagnoses such as “somatoform” and “somatic symptom disorders,” as well as “medically unexplained symptoms,” have been included in FSS (1). Although there is no complete consensus, FSS usually comprise of conditions such as fibromyalgia, irritable bowel syndrome (IBS), and chronic fatigue syndrome (CFS) (2). A characteristic of FSS is persistent physical symptoms that lead to impairment or disability and that disrupt the capacity to take part in daily life. Although FSS are believed to be caused by a complex interaction of biological and psychosocial factors (3), the conditions are not medically explained in terms of well-Understood or established pathophysiological mechanisms. Cognitive behavioral therapy (CBT) has become the gold standard psychological treatment for FSS. Several meta-analyses have shown a small to moderate effect in patients with FSS (4–7). Even though the small to moderate effect is robust, in the sense that results have been replicated both within and across conditions, there is limited research on treatment mechanisms (8). That is, CBT has an effect, but why the effect takes place is not firmly established. Traditional CBT rests on the idea that changing cognitions and behaviors in FSS will decrease somatic symptoms (9). Specifically, changing so-called dysfunctional illness beliefs “are of paramount importance for treatment (success)” (10). According to a review of Windgassen et al. (11), there is a “clear indication” that “cognitive change is important for reducing symptom severity.” Put simply, a patient who, for example, believes that “something is wrong with my body” or claims a physical attribution such as “I have a chronic infection, that is why I feel fatigued,” will not easily get well. There are some merits to this position. In a review of CBT for IBS, four out of five studies found cognitions to mediate the effect of treatment on symptom severity (11). In another review of CBT for CFS, three different types of illness perceptions (fatigue as something aversive, activity as potentially dangerous to health, and a symptom preoccupation with fatigue) were found to potentially perpetuate CFS symptoms (12). Although there is a value in the position that changing cognition is of “paramount importance” to reduce symptoms in FSS, we argue that this idea is a simplification and leaves several questions unanswered. In the following, we provide two major arguments against this position.

Objective: The aim of this study was to investigate emotional processing as a potential mediator in therapist-guided, internet-based Emotional Awareness and Expression Therapy (I-EAET) for somatic symptom disorder, using data from a previously published pilot study. Methods: Participants (N = 52) engaged in a 9-week I-EAET treatment. Before treatment and each week during treatment (i.e., 10 weekly measurements), emotional processing was assessed with the Emotional Processing Scale-25 (EPS-25), which contains five subscales, and somatic symptoms were assessed with the Patient Health Questionnaire-15 (PHQ-15). Results: Mediation analyses using linear mixed models showed that two EPS-25 subscales-Signs of Unprocessed Emotions and Impoverished Emotional Experience-were uniquely associated with somatic symptom reduction. The proportion of the mediated effect was 0.49, indicating that about half of the total association of the PHQ-15 with symptoms was accounted for by the two EPS-25 subscales. Conclusion: This preliminary mediation analysis suggests that improved emotional processing is associated with change in somatic symptoms in I-EAET. However, randomized controlled and comparison trials are needed to establish that I-EAET creates the change in emotional processing and that such changes are specific to I-EAET.

Background: There is growing evidence that trauma, psychosocial conflict, and difficulties with emotional processing contribute to centralized somatic symptoms. Emotional Awareness and Expression Therapy (EAET) was developed to address these factors and reduce symptoms, and EAET has shown efficacy in face-to-face formats. No trial of an internet-delivered EAET (I-EAET) exists, however, so we developed such an intervention and conducted an uncontrolled feasibility and potential efficacy trial of I-EAET for patients with Somatic Symptom Disorder (SSD) with centralized symptoms (SSD-CS).Method: After screening potential participants, a sample of 52 patients (50 women, two men; age M = 49.6, SD = 11.9) diagnosed with SSD-CS initiated treatment. I-EAET consisted of nine weekly modules focused on psychoeducation, emotional awareness and exposure, and anxiety regulation with self-compassion. Therapists communicated with each patient by email for about 20 min per week during treatment, answering questions and giving feedback on homework assignments. Patients completed measures of somatic symptoms, depression, anxiety, trauma-related symptoms, and functional disability before treatment and again at post-treatment and 4-month follow-up.Results: A large reduction in somatic symptoms (PHQ-15) occurred pre-to post-treatment (d = 1.13; 95% CI: 0.84–1.47) which was fully maintained at 4-month follow-up (d = 1.19; 95% CI: 0.88–1.56). Twenty-three percent of the patients at post-treatment and 27% at follow-up achieved a 50% or greater reduction in somatic symptoms, and about 70% achieved a minimally important clinical difference. In addition, at post-treatment, there were small to medium reductions (d's from 0.33 to 0.72) in anxiety (GAD-7), depression (PHQ-9), trauma-related symptoms (PCL-5), and functional disability (Sheehan Disability Scale). For all of these secondary outcomes, improvements were slightly to substantially larger at follow-up than at post-treatment (d's from 0.46 to 0.80).Conclusion: I-EAET appears to be a feasible treatment for adults with SSD and centralized symptoms, resulting in substantial and durable improvement not only in somatic symptoms but in other psychiatric symptoms and functioning. Controlled trials are needed determine the effects of I-EAET specifically and how this approach compares to face-to-face EAET and to other internet-delivered treatments, such as cognitive-behavioral interventions. Research should also identify treatment responders and mechanisms of change in EAET.Clinical Trial Registration:www.ClinicalTrials.gov, identifier: NCT04122846.

Patients with Myalgic encephalomyelitis/Chronic fatigue syndrome (ME/CFS) suffer from both subjective and objective poor sleep. Unrefreshing sleep is one of the diagnostic criteria in ME/CFS. Our studies indicate even increased parameters of alexithymia and decreased level of emotional awareness (LEAS) in ME/CFS patients as compared to healthy controls. This indicates difficulties in emotional regulation, however, the reasons for that are not known. To investigate if there is an association between objective sleep parameters with alexithymia and LEAS. 20 patients (5 men and 15 women) of age 43 (12) with BMI 24 (3) fulfill TAS-20 which measures alexithymia and LEAS. Sleep parameters were investigated by full-night polysomnography (PSG) at university hospital if investigation was motivated due to increased daytime sleepiness or other clinical indications. The use of clinical data for scientific analysis was considered by the regional ethical review board in Stockholm (Ref. no. 2014/300-31) and approved by Danderyd University Hospital (DS2014-0447). Written informed consent was obtained from all participants. Patients had overall impaired parameters in PSG as compared to norms. Spearman correlation analysis showed that difficulties to identify feelings in TAS-20 and total TAS-20 correlated negatively with sleep stages 3–4 (−0.632, p = .005 and −0.634, p = .005, respectively). LEAS correlated negatively with number of arousals (−0.6, p = .005). Results indicate that sleep stages responsible for emotional regulation are impaired in patients with ME/CFS. Shorter deep sleep is associated with higher alexithymia, especially in identifying feelings. Number of arousals might negatively affect emotional awareness and should be treated if possible.

Clinically, there is an overlap of several symptoms of chronic fatigue syndrome (CFS) and autism spectrum disorder (ASD), including fatigue; brain "fog"; cognitive impairments; increased sensitivity to sound, light, and odour; increased pain and tenderness; and impaired emotional contact. Adults with CFS (n = 59) or ASD (n = 50) and healthy controls (HC; n = 53) were assessed with the Autism-Spectrum Quotient (AQ) in a cross-sectional study. Non-parametric analysis was used to compare AQ scores among the groups. Univariate analysis of variance (ANCOVA) was used to identify if age, sex, or diagnostic group influenced the differences in scores. Patients with ASD scored significantly higher on the AQ than the CFS group and the HC group. No differences in AQ scores were found between the CFS and HC groups. AQ results were influenced by the diagnostic group but not by age or sex, according to ANCOVA. Despite clinical observations of symptom overlap between ASD and CFS, adult patients with CFS report few autistic traits in the self-report instrument, the AQ. The choice of instrument to assess autistic traits may influence the results.