Due to the serious consequences for quality of life and functioning, the occurrence of mental disorders in general and occupational populations have been intensively investigated in the past decade (Krueger et al., 1998; Lahelma et al., 2015). Symptoms related to distress, anxiety/depression or substance abuse/dependence--typically referred to as symptoms of common mental disorders (CMD)--are more frequently reported in young adults than at any other stage of the lifespan (American Psychiatric Association, 2013; Krueger et al., 1998; Korten and Henderson, 2000; King et al., 2008;). In sport, a recent literature study has shown that young elite athletes are confronted with 640 distinct stressors related to different issues such as leadership and personal issues, cultural and team issues, logistical and environmental issues, and performance and personal issues (Arnold and Fletcher, 2012). Consequently, the report of the occurrence of symptoms related to CMD among elite athletes during their sport career is not surprising (Gulliver et al., 2015; Schaal et al., 2011; Shuer and Dietrich, 1997; Walker et al., 2007). For example, 17% of French Olympic athletes reported having encountered mental problems in the past while nearly 45% of Australian elite athletes reported having experienced symptoms of CMD (Gulliver et al., 2015; Schaal et al., 2011).
In European football (soccer), scientific information about the occurrence of symptoms related to CMD among professional footballers across different European countries remains scarce (Gouttebarge and Aoki, 2014). This contrasts with the extensive amount of information available on the occurrence of musculoskeletal injuries among football players. In 2013, a pilot study among male professional footballers revealed that symptoms related to CMD were as prevalent as in other populations, ranging from 10% for distress to 19% for adverse alcohol use, and 26% for anxiety/depression (Gouttebarge et al., 2015a). These findings were recently supported in a large international study that demonstrated male professional footballers reported CMD symptoms that ranged from 9% for adverse alcohol use to 38% for anxiety/depression (Gouttebarge et al., 2015b; 2015c). In these studies, significant associations were found between symptoms related to CMD and both life events and career dissatisfaction (Gouttebarge et al., 2015a; 2015b). At the present time, a study on symptoms related to CMD among European professional footballers from different countries has not been published; nor is there one about the potential relation of these outcomes with major life events and career dissatisfaction. Accordingly, the aims of the present study were: (i) to determine the prevalence of symptoms related to CMD (distress, anxiety/depression, sleeping disturbance, adverse alcohol behaviour, adverse nutrition behaviour) in professional footballers from five European countries; and (ii) to explore associations of the outcome measures under study with life events and career dissatisfaction among professional footballers from five European countries.
This study was based on a cross-sectional design involving the baseline questionnaires from an on-going observational prospective cohort study.
Study setting and participants
Participants were professional footballers from five European countries: Finland, France, Norway, Spain and Sweden. Inclusion criteria were: (i) being a member, as an active player, of the national players' union from either Finland, France, Norway, Spain or Sweden. This means committing significant time to football training and competing at the highest and second highest professional football level within one of these countries; (ii) being 18 years or older; (iii) being male; and (iv) being able to read and comprehend texts fluently in either English, French or Spanish. With regard to the second aim of the study and with a preferred sample size requirement of 50 times the number of the independent variable (Woodward, 2013), the intended sample size was set at 50 participants per country. The World Players' Union (FIFPro) asked the national players' unions in Finland, France, Norway, Spain and Sweden to select potential participants from their members' lists at random (random numbers being provided by the responsible researcher). Potential participants were identified and invited between April and September 2014 to participate in the study by the national players' unions, procedures being blinded to the responsible researchers for reasons of privacy and confidentiality.
Symptoms related to common mental disorders
Distress: Distress in the previous four weeks was measured using the Distress Screener (3 items scored on a 3point scale), which is based on the four-dimensional symptom questionnaire (4DSQ) (Braam et al. 2009; Terluin et al., 2006). The 4DSQ, i.e. Distress Screener, has been validated in several languages, including English, French and Spanish (test-retest coefficients [greater than or equal to] 0.89; criterion-related validity: Area Under ROC Curve [greater than or equal to] 0.79) (Terluin et al., 2006; Braam et al. 2009). A total score ranging from 0 to 6 was obtained by summing up the answers on the three items, a score of 4 or above indicating the presence of distress (Braam et al. 2009; Terluin et al., 2006).
Anxiety/depression: The 12-item General Health Questionnaire (GHQ-12) was used to assess psychological symptoms related to anxiety/depression in the previous four weeks (Goldberg et al., 1997). The GHQ-12 has been validated in several languages, including English, French and Spanish (criterion-related validity: sensitivity [greater than or equal to] 0.70, specificity [greater than or equal to] 0.75, Area Under ROC Curve [greater than or equal to] 0.83) (Goldberg et al., 1997). Based on the traditional scoring system, a total score ranging from 0 to 12 was calculated by summing up the answers on the 12 items, with a score of 2 or above indicating signs of anxiety/depression (Area Under Curve = 0.88) (Goldberg et al., 1997).
Sleeping disturbance: Based on the PROMIS (short form), sleep disturbance in the previous four weeks was assessed through two single questions scored on a 4-point scale (0 for favourable answers, 1 for unfavourable answers) (Yu et al., 2011). The PROMIS has been validated in several languages, including English, French and Spanish (construct validity: product-moment correlations [greater than or equal to] 0.96), (for detailed information, see www..nihpromis.org). A total score ranging from 0 to 2 was obtained by summing up the answers to the two questions, a score of 1 or above indicating the presence of sleep disturbance (www..nihpromis.org).
Adverse alcohol behaviour: Current level of alcohol consumption was detected using the 3-item AUDIT-C (Dawson et al., 2005). The AUDIT-C has been validated in several languages, including English, French and Spanish (criterion-related validity: Area Under ROC Curve 0.70-0.97) (Dawson et al., 2005; De Meneses-Gaya et al., 2009). A total score ranging from 0 to 12 was obtained by summing up the answers on the three items, a score of 5 or above indicating the presence of adverse alcohol behaviour (Dawson et al., 2005).
Adverse nutrition behaviour: Current eating habits were examined using four statements validated in English and Dutch (e.g., 'I eat regularly throughout the day'), each to be answered by the number of days per week (from 0 to 7) (Van der Veer et al., 2011). Consuming healthy meals fewer than five days per week and eating regularly throughout the day fewer than three days per week and having breakfast before 10:30 fewer than three days per week and having a final meal before 20:30 fewer than three days per week was reported as adverse nutrition behaviour (Van der Veer et al., 2011).
Life events (LE): Based on the validated Social Athletic Readjustment Rating Scale, the occurrence of life events (e.g. 'Death of spouse', 'Change in financial state') was explored by 13 single questions (yes or no) (Bramwell et al., 1975). We chose to explore the occurrence of life events either in the previous six months (LE6) as one might assume that some life events (for instance 'conflict with coach/trainer') might be more relevant if they occurred recently rather than three years ago. Two scores (LE6) were calculated by summing up the life events occurred.
Career dissatisfaction: Professional football career dissatisfaction was explored through the validated Green-haus scale (e.g. 'I am satisfied with the success I have achieved in my career') (5 items on a 5-point scale) (Greenhaus et al., 1990). A total score ranging from 5 to 25 was obtained by summing up the answers to the five items, a lower score indicating a higher level of dissatisfaction.
Based on the stressors and outcome measures under study, an electronic questionnaire was set up (FluidSurveys[TM]) in English...