STPP for Functional Somatic Disorders 1 Short-term Psychodynamic Psychotherapy for Functional Somatic Disorders: A Meta-analysis of Randomized Controlled Trials Running Head: STPP for Functional Somatic Disorders

Introduction: Functional somatic disorders (FSD) are common and costly, thereby driving the need for the development of effective brief treatment options. Short-term Psychodynamic Psychotherapy (STPP) is one candidate treatment method. Objective: To review and metaanalyse, where possible, randomized controlled trials (RCTs) of STPP for FSD. Methods: Following a systematic search of the literature, we performed a meta-analysis of available groups of RCTs of the effects of STPP on a range of outcomes at post-treatment, mediumand longterm follow-up. Results: In meta-analyses of 17 RCTs, STPP significantly outperformed minimal treatment, treatment-as-usual or waitlist controls on somatic symptom measures at all time frames, with small to large magnitude effect sizes. Descriptive reviews of five RCTs suggest that STPP performed at least as well as other bona fide psychological therapies. Limitations of this meta-analysis include small samples of studies and possible publication bias. Conclusions: STPP is a valid treatment option for diverse FSD conditions resulting in somatic symptom reductions that persist over time. STPP should be included in FSD treatment guidelines. STPP for Functional Somatic Disorders 3 Short-term Psychodynamic Psychotherapy for Functional Somatic Disorders: A Meta-analysis of Randomized Controlled Trials Introduction Functional somatic disorders (FSD) are a collection of conditions with distressing symptoms related to functional impairments in neurobiological systems implicated in pain and emotion regulation. FSD is an umbrella term that includes somatoform disorders, psychophysiological disorders, so-called medically unexplained symptoms, and most conditions under the rubric of DSM-5 somatic symptom and related disorders [1]. These conditions account for up to one-half of primary care visits and medical consultations as well as an excess of hospital days, medications, investigations, and disability costs [2-4]. Given the major health system and patient burden of these disorders coupled with access limitations to public mental health services, the establishment of efficacious short-term therapies is of prime importance [5]. Short-term psychodynamic psychotherapies (STPP) are treatments of 40 or fewer sessions that emphasize psychodynamic concepts and techniques. These interventions share a focus on emotional and relational processes that are linked to developmental deficits, unresolved conflicts, and past adverse experiences. These methods commonly use the triangle of conflict linking feelings, anxiety and defenses, and the triangle of person linking past, current and therapeutic relationship experiences [6]. The methods also emphasize unconscious content in terms of thoughts, fantasies and feelings tied to adverse life events. The range of techniques used in STPP include supportive techniques, interpretation, challenge to defenses, efforts to develop insight, and efforts to experience and express unprocessed feelings related to adverse events and psychological conflicts (See Figure 1). These treatment elements are distinguishable from cognitive behavioral therapy techniques [7]. For these reasons, STPP is considered a type of therapy that is distinct and can be studied as a collection even while technical treatment details vary among STPP subtypes [8]. Some forms of STPP, such as Intensive Short-term Dynamic Psychotherapy (ISTDP) [9, 10] and Emotional Awareness and Expression Therapy (EAET) [11] emphasize helping the patient to somatically experience and process unconscious feelings to correct emotion dysregulation underlying somatic symptoms in FSD [12] while other methods such as Time Limited Dynamic Psychotherapy [13], Luborsky’s Supportive Expressive Therapy STPP for Functional Somatic Disorders 4 [14] and Malan’s Short-term Dynamic Psychotherapy [6] emphasize building insight into unconscious processes more so than emotional experiencing. STPP methods have been studied in over 250 randomized controlled trials for a wide range of conditions [15]. STPP has been found efficacious for depression [16], anxiety [17], personality disorders [18] and common mental disorders in general [8]. In 2009, we reported on 23 trials of STPP for mixed somatic conditions and found it to be effective and superior to controls, with moderate to large treatment effects that tended to be sustained or increase at follow-up [19]. That meta-analysis, however, included only 7 RCTs of FSD, whereas the others were uncontrolled or non-randomized studies, and some examined clear somatic diseases such as Crohn’s disease [20] and rheumatoid arthritis [21] rather than FSD. Alongside RCTs, meta-analyses are currently placed at a high level of evidence and are commonly used to inform treatment guidelines, despite the fact that meta-analysis is controversial because of limitations in this research method [22]. Where possible, clinical expertise integrated with a review of the literature may be more clinically useful. Along this line, Henningsen and colleagues recently reviewed the literature on FSD and concluded that emotional factors including adverse childhood experiences, attachment disorders, personality disorders and problems identifying emotions are risk factors for FSD [23]. They also concluded that treatments such as STPP, which focus on the emotional impacts of childhood adversity and personality dysfunction, may be clinically useful [23]. Given these recommendations and the need for a current estimate of the impact of STPP on FSD, here we provide an updated review and meta-analysis. In this review, we included only RCTs and excluded studies of somatic conditions or diseases with known structural pathology. We meta-analyzed RCTs that compared STPP to treatment-as-usual/waiting list/minimal treatment and targeted somatic symptoms as the primary outcome at three separate follow-up time-points used in previous STPP meta-analyses [8]: shortterm (<3 months), medium-term (3-9 months) and long-term (>9 months). We also conducted meta-analyses of subgroups of RCTs based on certain methodological features, treatment characteristics, or disorder types to determine the effects of STPP in more homogeneous samples. Finally, we provide a brief descriptive review of RCTs that compared STPP to bona fide comparator psychological interventions. STPP for Functional Somatic Disorders 5