Table 1.

Summary of Reviewed Studies.

Reference	Year	Sample Size	Relevant ICD-11 Classifications	Description of Findings
Morgan et al. [14]	1987	n = 400	Depression	Summary of 10-year study of endurance swimmers evaluated for mood using Profile 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 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.
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 specifically (F(1) = 9.30, p < 0.001). More anxiety/panic symptoms were found in paddlers (χ2 = 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 (χ2(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 deficit, 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 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 find 30% participants at risk and symptomatic of EXD.
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 find 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 risk for EXD were also at risk for ED, measured by the ED Examination Questionnaire (EDE-Q), and showed evidence of low energy availability.
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. [59]	2022	n = 123	Eating disorder	Ultramarathoners assessed using proprietary survey consisting of questions from Female Athlete Triad Screening Questionnaire and Eating Disorder Examination Questionnaire. Risk of ED found in 44.5% of males and 63.5% females. Evidence of bone-stress injury (BSI) found in 37.5% of females and 20.5% of males using dual-energy X-ray absorptiometry (DXA).