Mental Health Disorders in Ultra Endurance Athletes per ICD-11 Classifications: A Review of an Overlooked Community in Sports Psychiatry

ntroduction: Although research suggests that exercise bene ts mental health, psychiatric disorders have been acknowledged in the ultra-endurance-athlete population. At present, the mental- health consequences of high-volume training associated with ultra-endurance sports are not well understood. Methods: We conducted a narrative review summarizing primary observations about mental disorders per ICD-11 criteria in ultra-endurance athletes using a keyword search in Scopus and PubMed. Results: We identi ed 25 papers discussing ICD-11-classi ed psychiatric disorders such as depression, anxiety, eating disorders, attention-de cit/hyperactivity disorder, and schizophrenia in ultra-endurance athletes. Discussion: Although evidence is limited, available papers indicate that there is a sizable incidence of mental-health issues and composite psychopathological vulnerabilities in this community. We contend that ultra-endurance athletes may represent a different, though similar, demographic than elite and/or professional athletes, as they often engage in high-volume training with similarly high motivation. This can have regulatory implications, which we also highlight. Conclusion: Mental illness in ultra-endurance athletes is an underrepresented topic in sports medicine, though psychiatric disorders may be especially prevalent in this population. Further inquiry is necessary to inform athletes and healthcare practitioners about the possible

elite and/or professional athletes, as they often engage in high-volume training with similarly high motivation. This can have regulatory implications, which we also highlight. Conclusion: Mental illness in ultra-endurance athletes is an underrepresented topic in sports medicine, though psychiatric disorders may be especially prevalent in this population. Further inquiry is necessary to inform athletes and healthcare practitioners about the possible mental-health implications associated with participation in ultra-endurance sports. Keywords: ultra-endurance athletes; sports psychiatry; mental disorders; training volume; ICD-11; endocrine dysfunction 1. Introduction There is evidence of increased psychiatric disorders in the ultra-endurance-athlete (UEA) population, despite the known mental-health bene ts of exercise [1]. Anecdotally, it could be argued that mental illness is a commonly recognized feature of the UEA com- munity [2]. Mental-health improvements have been noted in individuals exercising at moderate yet consistent volumes [3–6]. Resistance exercise has been known to improve brain structure, function, and connectivity through regulation of neurotrophic factors [7]. Speci cally, brain-derived neurotrophic factor (BDNP) may have antidepressant effects [8], suggesting some measure of exercise can help prevent psychiatric issues [9]. However, discussion of UEA training volumes indicates that they are exercising beyond moderation, as high-volume training is a necessary characteristic of participation in ultra-endurance sports (UESs) like ultramarathon, Ironman triathlon, mountain sports, endurance cycling, or endurance swimming [10]. Although there is no speci c de nition of UES races, they typically span durations over six hours or over several days and appropriate training includes continual addition of volume [11]. Accordingly, our criteria for UEAs follows the classi cations proposed by Scheer and Knechtle and Nicolaidis [10,11]—that is, athletes Sports2023,11, 52.

Sports2023,11, 52 2 of 15 training for ultramarathons of any distance over 42 km or other ultra-distance events lasting six hours or more. Investigations show that psychiatric issues may result from multiple hours of competition in an intra-race situation or from wider circumstantial paradigms, like the COVID-19 pandemic [12,13]. Although they provide useful insights, we believe that these studies do not fully capture the intrinsic psychological pro le of the athlete, independent of external and contextual factors. In the limited investigations available, high-volume training is associated with a decrease in athlete well-being and a decline in mood [14–18]. Despite indications of psychiatric issues and the publication of a review article intro- ducing this topic [1], there have been no formalized efforts to collate extant information to create an of cial mental-health statement about this community. This contrasts with other sporting domains, where researchers have developed guidelines for both high-performance athletes [19] and elite athletes [20]. Correspondingly, there are minimal regulatory interven- tions around mental health in UEAs, particularly as UESs are heterogeneous and involve multiple stakeholders internationally. This is distinct from more established sporting dis- ciplines that may be subject to greater scrutiny and emphasize mental health initiatives, such as those addressed by the formulation of organizations like the International Olympic Committee Mental Health Working Group [21]. A UEA may be elite or recreational, though they might be training at similar levels of volume and intensity and can be driven by similar intensity of motivation as high- performance athletes [22,23]. Recreational athletes may experience additional pressures associated with balancing heavy training loads with professional and familial responsibili- ties without the bene t of a support team [24]. Additionally, it is acknowledged within the community that UEAs often drift from one sport to another, as their physical capabilities, motivations, and interests draw them to complementary challenges. First-hand opinions support this; for instance, the Ironman world-champion triathlete, Sika Henry, has observed these patterns [25]. To the authors' knowledge, detailed research into these considerations is limited and comprehensive evidence on the prevalence of mental disorders in UEAs is scarce. Moreover, it is not

sport to another, as their physical capabilities, motivations, and interests draw them to complementary challenges. First-hand opinions support this; for instance, the Ironman world-champion triathlete, Sika Henry, has observed these patterns [25]. To the authors' knowledge, detailed research into these considerations is limited and comprehensive evidence on the prevalence of mental disorders in UEAs is scarce. Moreover, it is not well understood whether there are athletes that gravitate toward UESs speci cally with the intention of ameliorating preexisting psychiatric symptoms or whether participation in UESs incurs neuropsychological change such that mental disorder de- velops [1]. There has been broad media coverage of UEAs who use participation in their sport to manage existing symptoms related to post-traumatic stress disorder (PTSD), attention-de cit/hyperactivity disorder (ADHD), autism-spectrum disorder (ASD), and alcohol-use disorder [26–30]. Alternatively, preliminary neurological work into UEAs suggests that high-volume training affects neurotransmitter balance, contributing to risk factors for mental-health issues [31]. Resulting 5-HTTPLR polymorphism may be correlated with severe depression and has links with increased amygdala activation in situations of anger [31,32]. Moreover, the COMT val 158 met polymorphism critical to the regulation of dopamine may also be prevalent in UEAs, causing athletes to be more prone to novelty- seeking behavior, which has been associated with bipolar disorder, ADHD, psychosis, substance-use disorders, and suicide [33]. Given the forensic–psychiatric implications of potentially increased emotional reactivity, this lack of information is again concerning [34]. More generally, both onset possibilities would create similar, though unique, considerations in the UEA community requiring additional education and possible tailored interventions. To address these knowledge gaps, we performed a narrative review to synthesize cur- rent literature about mental disorder in UEAs. We summarized our results and thematized psychiatric symptoms per diagnostic classi cations from the ICD-11 (as distinct from the DSM-V) and focused our search on the World Health Organization's (WHO) list of the most prevalent mental disorders [35–37]. Based on the evidence we collated, we discuss our ndings and their relevance for UEAs in the broader framework of sports medicine and sports psychiatry.

distinct from the DSM-V) and focused our search on the World Health Organization's (WHO) list of the most prevalent mental disorders [35–37]. Based on the evidence we collated, we discuss our ndings and their relevance for UEAs in the broader framework of sports medicine and sports psychiatry.

Sports2023,11, 52 3 of 15 2. Methodology We searched two academic databases in November 2022, Scopus and PubMed, for scholarly materials on UEAs and mental disorders as classi ed within ICD-11 diagnostic domains [35]. No timeframe parameters for published materials were adopted in our methodology. The search was conducted using the terms “ultra-endurance athlete,” “ul- trarunner,” “ultramarathoner,” “endurance cyclist,” “triathlete,” “mental disorder,” and “mental illness,” along with terms from the WHO's list of the most common mental disor- ders: “depression,” “anxiety,” “bipolar,” “post-traumatic stress disorder,” “schizophrenia,” “eating disorder,” “attention-de cit/hyperactivity disorder,” and “autism” [36]. Subse- quently, we manually added pertinent articles from applicable reference lists. Following this, we removed papers that did not report primary empirical observations (e.g., review articles), duplicates, and those not written in the English language. Furthermore, we ex- cluded samples that did not ful ll our de nition of ultra-endurance sports as delineated above and where this could not be de nitively determined from cohort descriptions. In addition, we omitted papers designed to reveal mental-disorder concerns exclusively due to other contextual factors, like the COVID-19 pandemic, or psychiatric and psychological issues speci cally resulting from in-competition conditions. 3. Results Per our search criteria, we identi ed 25 papers that show evidence of mental disorder in UEAs. Studies included in our review are summarized in Table with an outline of their methods, instrumentation, and results. Table 1.Summary of Reviewed Studies. Reference Year Sample Size Relevant ICD-11 Classi cations Description of Findings Morgan et al. [14] 1987 n= 400 Depression Summary of 10-year study of endurance swimmers evaluated for mood using Pro le of Mood States (POMS) over a 6-month training block. In all years, mood decreased during the highest-volume training period. A total of 80% were diagnosed with clinical depression. Morgan et al. [15] 1988 n= 12 Depression Swimmers assessed daily with POMS during a 12-day high-volume block. As training volume increased, sense of well-being and mood decreased, depression increased. DeBate and Wethington [38] 2001 n= 583 Eating disorder Triathletes assessed for disordered eating using Eating Attitudes Test-26 (EAT-26). A total of 28% of females, 11% males

with clinical depression. Morgan et al. [15] 1988 n= 12 Depression Swimmers assessed daily with POMS during a 12-day high-volume block. As training volume increased, sense of well-being and mood decreased, depression increased. DeBate and Wethington [38] 2001 n= 583 Eating disorder Triathletes assessed for disordered eating using Eating Attitudes Test-26 (EAT-26). A total of 28% of females, 11% males at risk for eating disorder (ED). Evidence of preoccupation with food/weight, calorie control. A total of 100% of participants express body dissatisfaction using Body Test Material. Blaydon and Lindner [39] 2002 n= 203 Eating disorder Triathletes assessed for EXD and ED using Exercise Dependence Questionnaire (EDQ) and EAT. A total of 30.6% of cohort at risk for primary EXD, 21.6% at risk for secondary EXD, 12.3% at risk for ED.

Sports2023,11, 52 4 of 15 Table 1.Cont. Reference Year Sample Size Relevant ICD-11 Classi cations Description of Findings Harrison et al. [40] 2003 n= 33 Depression Study designed to evaluate the effect of triathlon race on depression using Beck Depression Inventory II. A total of 21% of participants were diagnosed with, and 12% in treatment for, mood disorders. Depression score not associated with mood during race. Kiraly and Joy [41] 2003 n= 1 Depression, psychosis Case study of male Ironman triathlete with ED, depression, and psychosis. Yates et al. [42] 2003 n= 190 Eating disorder, anxiety disorder, fear-related disorder Ultra-endurance runners, cyclists, and paddlers examined for ED using Exercise Orientation Questionnaire (EOQ) and self-report of psychiatric symptoms. Risk of ED found in 12% runners, 14% cyclists, and 18% paddlers. Self-loathing was associated with ED symptoms for the entire group (F(1) = 4.8,p< 0.05) and for females speci cally (F(1) = 9.30,p< 0.001). More anxiety/panic symptoms were found in paddlers (c2 = 7.91, p< 0.01). Paddlers had higher self-loathing scores than cyclists (F(2) = 6.91,p< 0.01). The most anxiety/panic symptoms were reported by the female-only paddler group (c2(1) = 10.27,p< 0.001) than the other groups. Millet and Groslambert [18] 2005 n= 4 Anxiety disorder Elite triathletes evaluated for fatigue and anxiety using a questionnaire unique to the study over a 40-week training block. Increased training loads were correlated to higher anxiety and fatigue. Hoch et al. [43] 2007 n= 15 Eating disorder Study of disordered eating measured by EAT-26 and bone-mineral density measured by dual-energy x-ray absorptiometry in club triathletes. A total of 60% in caloric de cit, 40% with history of amenorrhea. Riebl et al. [44] 2007 n= 61 Eating disorder Male cyclists were assessed for ED using EAT-26 and Survey of Eating Disorder Among Cyclists (SEDAC). Risk of ED found in 19.7%. A total of 45.9% of cyclists believed ED to be common in cycling. Axelsen [45] 2009 n= 1 Eating disorder Autoethnographic case report of one female triathlete with anorexia nervosa. Magee et al. [46] 2016 n= 345 Eating disorder, depression Study designed to reveal correlations between exercise

Survey of Eating Disorder Among Cyclists (SEDAC). Risk of ED found in 19.7%. A total of 45.9% of cyclists believed ED to be common in cycling. Axelsen [45] 2009 n= 1 Eating disorder Autoethnographic case report of one female triathlete with anorexia nervosa. Magee et al. [46] 2016 n= 345 Eating disorder, depression Study designed to reveal correlations between exercise dependence (EXD), eating patterns as measured by the Three Factor Eating Questionnaire (TFEQ), and psychological distress/depression symptoms as measured by the Kessler 6 Scale in Ironman triathletes. Exercise Dependence Scale (EDS) used to nd 30% participants at risk and symptomatic of EXD.

Sports2023,11, 52 5 of 15 Table 1.Cont. Reference Year Sample Size Relevant ICD-11 Classi cations Description of Findings Sanhuenza et al. [47] 2016 n= 192 Anxiety disorder, alcohol-use disorder Triathletes were assessed by psychiatric interview (MINI international neuropsychiatric interview, 5.0), genotyping analysis of ACE rs1799752 (I/D), and serotonin transporter 5HTT (5-HTTLPR). Anxiety disorder was a risk for 44.3% of total participants and 57% of Inferior Performance (IP) group. IP showed higher frequency of polymorphisms for 5-HTTLPR, which is associated with increased anxiety; 5HT1AR-1019C > G, which is associated with anxiety disorder; and NK1R r56715729, which is associated with stress homeostasis, alcohol dependence, and alcohol abuse. Cook et al. [48] 2017 n= 179 Eating disorder Study of male cyclists used EDS, Drive for Thinness, and Leisure Time Exercise Questionnaire to nd that 8.24% were at risk and 70% were symptomatic for primary exercise dependence. A total of 1.18% were at risk and 10.59% were symptomatic for secondary exercise dependence, suggesting presence of ED. EXD more prevalent with more frequent workouts. Mayolas et al. [49] 2017 n= 859 Anxiety disorder, depression Amateur endurance cyclists assessed for exercise addiction using Exercise Addiction Inventory (EAI), Quality of Life (QoL), and anxiety and depression (Hospital Anxiety and Depression Scale). Evidence of EA found in 17% of cyclists. Lower QoL, assessed by Short Form Survey version 2.0–12, was observed in the at-risk group. EA not related to training volume. Buck et al. [50] 2018 n= 98 Depression Ultramarathoners assessed for exercise addiction and depression using EAI and PHQ-2. A total of 20% of athletes were positive for EA risk and 20% were positive for depression risk. Schüler et al. [51] 2018 n= 323 Anxiety disorder Study designed to assess predictors of exercise addiction in ultra endurance athletes using Balanced Measure of Psychological Needs Scale (BMPN), the anxiety-oriented self-control subscale of the Volitional Components Inventory, and EAI. Overall sample scored high on EAI with the mean score at cut-off for EA. Torstveit et al. [52] 2019 n= 53 Eating disorder Exercise dependence, measured by EDS, correlated with higher training volume in male cyclists and triathletes. Those at

athletes using Balanced Measure of Psychological Needs Scale (BMPN), the anxiety-oriented self-control subscale of the Volitional Components Inventory, and EAI. Overall sample scored high on EAI with the mean score at cut-off for EA. Torstveit et al. [52] 2019 n= 53 Eating disorder Exercise dependence, measured by EDS, correlated with higher training volume in male cyclists and triathletes. Those at risk for EXD were also at risk for ED, measured by the ED Examination Questionnaire (EDE-Q), and showed evidence of low energy availability.

Sports2023,11, 52 6 of 15 Table 1.Cont. Reference Year Sample Size Relevant ICD-11 Classi cations Description of Findings Hauck et al. [53] 2020 n= 1022 Eating disorder In a study of amateur endurance athletes, the prevalence of food addiction, measured by the Yale Food Addiction Scale 2.0, was 6.2%. Prevalence of ED, measured by the Eating Disorder Diagnostic Scale (EDDS), was 6.5%. Prevalence of exercise addiction, measured by the Questionnaire to Diagnose Exercise Dependence in Endurance Sports (FESA), was 30.5%. Results unrelated to the number of training hours per week. Muros et al. [54] 2020 n= 4037 Eating disorder Study of endurance cyclists and triathletes found 17.9% at risk for ED measured by the revised restraint scale (RRS), SCOFF questionnaire, and Mediterranean Diet Adherence Screener (MEDAS); higher in females and cyclists, lower in males and triathletes. Bueno-Antequera et al. [55] 2022 n= 330 Alcohol-use disorder Amateur endurance cyclists assessed for exercise addiction using EAI, QoL, using Health Survey 2.0. EXD risk found in 64% of males and 60% females. Lower mental QoL and increased alcohol use was found in 14.8% of participants. Cook and Dobbin [56] 2022 n= 36 Eating disorder Male cyclists assessed for ED risk using the Sports Nutrition Knowledge Questionnaire (SNKQ) and Brief Eating Disorder in Athletes Questionnaire (BEDA-Q). Risk for ED was high in 11% of group and negatively correlated with understanding of nutrition (r= 0.55,p= 0.006). Koppenburg et al. [57] 2022 n= 122 Eating disorder Female cyclists were assessed for ED risk (EAT-26). A total of 32% were found to be at risk and 80% percent of those surveyed believed cycling to be associated with high ED risk. Colledge et al. [58] 2022 n= 123 Depression High-performance athletes were assessed for EXD using the EXD Scale, evidence of childhood trauma using the Childhood Trauma Questionnaire (CTQ), ADHD using the Homburger ADHS Skalen für Erwachsene (HASE), and depression using the BDI. EXD risk found in 23.6% and those with EXD had higher likelihood of depression (t(121) = 4.944, p< 0.001), ADHD (t(121) = 2.915,p= 0.004), and childhood trauma (t(121) = 2.297, p= 0.024). Høeg et al.

A review of mental health disorders in ultra-endurance athletes, focusing on ICD-11 classifications.