in the substance - related disorders section , the diagnostic and statistical manual of mental disorders , fifth edition , dsm-5 , includes only gambling disorder as form of addiction that does not involve ingestion of substance , reflecting evidence that this repetitive behavior activates reward systems as well as drugs of abuse [ 2 , 3 ] .
it is noteworthy that in clinical practice we observe a clustering of different excessive and repetitive behaviors , with symptoms that appear comparable to those produced by gambling , involving hedonistic ( e.g. ,  sex addiction  ) or nurturant motives ( e.g. ,  exercise addiction ,   shopping addiction ,  and  internet addiction  ) .
actually , these addictive behaviors , although showing strong neural similarities to substance addiction , are not included in any official recognized medical or psychological frameworks because there is not enough peer - reviewed evidence to establish diagnostic criteria .
regular and moderate physical activity plays a lead role in the maintenance of health and in disease prevention .
for instance , it can reduce the risk of cardiovascular diseases , diabetes , colon and breast cancer [ 810 ] , and depression and anxiety [ 11 , 12 ] .
moreover , adequate levels of physical activity will decrease the risk of a hip or vertebral fracture and help in weight control .
exercise is a subcategory of physical activity that is planned , structured , and repetitive with the aim of improving or maintaining one or more components of physical fitness .
habitual exercise shows significant benefits for both physical and mental well - being in adults , children , and teenagers . even in mental disorders ,
future modern therapeutic approaches should include physical exercise as part of multimodal intervention programs aimed to improve psychopathology and cognitive symptoms .
the term  exercise addiction  was first used to underlie the beneficial aspects of habitual exercise in contrast to drug or alcohol abuse or other self - destructive behaviors .
positive  addiction because of its beneficial effects on well - being , until it was clear that , in many cases , overtraining and overexercise were associated with increased susceptibility to injuries or with sociooccupational dysfunctioning .
morgan   labeled cases of extreme overuse of exercise as new forms of  negative  addiction .
exercise addiction could turn the positive psychosocial effects of regular physical activity into a detrimental activity when affected subjects experience overpowering drives .
this conceptualization is in line with the theory of the long - term negative effect of any type of addiction , since addictions may alter the subjective experience of the self and are often seen as a failure of self - regulation .
szabo reported that addicted exercisers could experience deprivation symptoms with strong adverse effects on subjective states and well - being .
it is almost well known that addictive behaviors do not develop abruptly ; rather they evolve through a process made up of several stages . according to the theoretical model of behavioral addictions [ 20 , 21 ] ,
exercise addiction should include the following components : salience , when exercise becomes the most important thing , mood modification , occurring when people adopt a coping strategy to regulate emotions , tolerance , a physiological increase of the amount of exercise required to reduce craving , withdrawal , as manifested by anhedonia and anxiety when gym activity is suddenly reduced , conflicts between the addicted person and others , and relapse , the tendency to repeated reversions to earlier patterns of the activity .
another important aspect to consider is the distinction between primary exercise addiction when the exercise itself is the main aim and secondary exercise addiction that is generally a consequence of an eating disorder and serves the purpose of weight control .
some authors argue that exercise addiction does not exist in absence of an eating disorder , whereas others suggest the hypothesis that exercise addiction is separate from eating disorders , although it may share some of concerns about body and performance .
research about the association between exercise addiction and eating disorders has definitely shown conflicting results .
as other addictive behaviors , exercise addiction should also be differentiated from compulsions and impulse control disorders .
addicted subjects are egosyntonic and enjoy what they are doing , whereas obsessive - compulsive subjects are egodystonic and dislike their obsessions although they feel compelled by them [ 25 , 26 ] .
the prevalence of exercise addicted in general population is about 3% . among italian adolescents a rate of prevalence of 8.5% of exercise addiction
the overall negative consequences of exercise addiction suggest the need to identify possible risk factors for the development of the disorder ; among these factors , self - esteem in behavioral addictions was explored in cross - sectional and longitudinal studies that have shown an association between internet addiction and low self - esteem   but its direct role in development of exercise addiction has never been investigated . 

carter et al . suggested that trait anxiety and obsessive - compulsiveness were associated with a higher commitment to exercise and narcissism with greater physical activity .
narcissistic traits have been also found in substance - addicted adolescents , and high cooccurrence rates of substance and alcohol abuse and dependence have been found in adults with narcissistic personality disorder .
moreover , longitudinal studies have shown that narcissistic personality disorder in adolescents could be a predictor of subsequent substance use disorder .
the aim of this study was to expand on these previous findings assessing narcissistic traits and self - esteem in a sample of gym attenders .
we hypothesized that self - esteem and narcissism may have a role in the development of exercise addiction .
150 consecutive gym attenders , recruited in fitness centers , were asked to participate in the study .
the study was introduced to the participants as an investigation into attitudes and beliefs about exercise activity and personality .
data were collected using a sociodemographic questionnaire ; we evaluated the frequency of physical activity assessing the number of the days in the week with more of 3 hours of exercise in the fitness center .
the exercise addiction inventory ( eai )   was used to identify subjects at risk for exercise addiction .
eai is a self - report , six - item questionnaire with a five - point likert response option ranging from 1  strongly disagree  to 5  strongly agree . 
the measure is based upon the six components of exercise addiction according to griffiths et al . .
the narcissistic personality inventory ( npi ) [ 37 , 38 ] was used to estimate narcissistic components .
npi is a 40-item self - report questionnaire based on dsm - iv - tr criteria for narcissistic personality disorder .
it identifies seven factors ( authority , exhibitionism , superiority , entitlement , exploitativeness , self - sufficiency , and vanity ) associated with narcissistic traits .
the coopersmith self - esteem inventory ( sei )   was used to assess self - esteem on the basis of attitudes toward oneself and others and personal interests .
respondents are asked to state whether 50 favorable or unfavorable aspects of a person are  like me  or  not like me .  data
obtained from the study underwent check and quality control and , subsequently , descriptive and inferential statistical analysis .
t - test was used to compare age , numbers of days per week of exercise activity , self - esteem , and narcissistic components between groups ; noncontinuous data were expressed as percentages and chi - square analysis was used to test gender distribution .
effect size was provided by using cohen 's d statistic and was considered small when being lower than 0.50 , moderate when ranging from 0.50 to 0.79 , and large when being equal to or greater than 0.80 .
all the variables that reached statistical significance underwent correlational analyses ; a linear regression analysis was further performed in order to evaluate the association between narcissistic features , self - esteem , and exercises ' characteristics . a stepwise method
statistical analyses were performed using statistical package for the social sciences  spss 21.0 software ( spss inc . , chicago , il , usa ) .
from a total sample of 150 gym attenders , 120 subjects completed the study . based on eai total score , a high ea risk group ( hea : n = 51 , mean age = 29.7 ) was identified .
low ea risk group ( lea ) was formed by 69 subjects ( mean age = 32.2 ) .
the prevalence rate of ea risk in gym attenders was 42.5% ; no gender differences in the rate of risk for exercise addiction were found ( table 1 ) .
hea subjects reported significantly lower sei total score ( mean = 32.2 versus 36.4 ) and higher npi total score ( mean = 20.2 versus 14.6 ) than lea group , as shown in table 2 .
narcissism ,   self - sufficiency ,   superiority ,   exhibitionism , 
 exploitativeness ,  and  vanity  scores , and small in sei total score .
all the variables that reached statistical significance ( days per week exercise , as dependent variables , and self - esteem , narcissism total score , and three narcissism factors scores , as independent variables ) were analysed in a linear regression model . as a block
, the 5 predictors accounted for 15.4% of the total variance in exercise frequency ( f = 2.537 ; df = 5 ; p = 0.039 ) ( table 3 ) .
furthermore , stepwise regression analysis provided two models : in the first one ( table 4 ) self - esteem , authority , superiority , and exploitativeness were excluded and only narcissism resulted in a predictor of exercise frequency ( f = 6.2 ;  df = 1 ;  p = 0.015 ) , accounting for the 7.9% of the variance ; the second one ( table 5 ) indicated that narcissism and self - esteem as a block ( f = 5.66 ;  df = 2 ;  p = 0.006 ) were good predictors of days per week exercise , whereas other scales did not give a significant additional contribution to the prediction of exercise frequency .
the present study was designed to evaluate narcissistic traits and self - esteem in a sample of high ea risk subjects compared with ea low risk controls .
the results obtained showed that specific narcissistic traits were associated with the risk for exercise addiction .
this is congruent with previous findings showing that highly committed exercisers had substantially higher levels of narcissism with greater physical activity than less committed exercisers .
the role of narcissism in development of addiction has been addressed since freud , who considered substance use as a narcissistic object choice in which substance itself represents an oral extension of the ego . in general
the fulfilling of narcissistic drives is mediated by repetitive behaviors that assure omnipotence and provide protection against the potential lack of gratification or admiration .
the association between narcissism and addiction raises the following question : which is the object , the substance , or the activity to which the narcissistic subject should become addicted ? according to morf and rhodewalt , in narcissistic persons , the focus of addiction might be on the grandiose view of self , not on the approval from others .
if the admiration of other people is not the goal in itself , narcissism may be characterized by cognitive distortions that exaggerate the importance of the self , even without receiving confirmation from others . within this context
this attitude has been defined as  narcissistic myopia  , a condition in which social skills and interpersonal judgment are neglected , whereas only the desire for admiration is cognitively processed . in such context ,
narcissistic features ( superiority , authority , and exploitativeness ) may become themselves addictive craving behaviors .
narcissistic subjects also seem highly susceptible to tolerance , since they continuously need to increase the search for claims and triumphs , and to withdrawal , since they show emotional symptoms when receiving something different from the admiration they seek .
have explored the relationship between exercise identity and exercise dependence , according to the assumption that exercise identity promotes behaviors consistent with the perceived role of the exerciser .
they found that  exercise beliefs ,  a component of exercise identity , were significantly associated with the odds of experiencing dependence symptoms , whereby  exercise role identity , 
the other component of exercise identity , was not significantly associated with the same odds . moreover , the authors suggested the need for further research examining other factors possibly related to exercise addiction , such as identity , affect , self - esteem , and self - efficacy .
our results showed that hea subjects were characterized by lower self - esteem when compared with lea subjects .
this result extends to exercise addiction previous findings on the role of low self - esteem in the development of other addictions , as internet or online game addiction .
low self - esteem was also found in an italian sample of subjects affected by exercise dependence .
hall et al .   argued that social prescribed perfectionism had a direct positive effect on exercise addiction and , as perfectionism is linked with contingent self - worth , labile self - esteem may mediate the relationship between unconditional self - acceptance and exercise dependence .
first of all , the cross - sectional design does not allow considering changes over time .
furthermore , to evaluate concomitant psychopathological symptoms , such as eating disorders or muscle dysmorphia , it would have been more accurate to perform a clinical interview
. finally , although the frequency of exercise may not be directly related to the risk for exercise addiction , since professional athletes exercise more often and longer than subjects at risk for exercise addiction , we selected 
days per week  as the dependent variable in the regression analysis . other models may have a stronger rationale to be tested .
the first aim of this study was the assessment of prevalence of the risk of exercise addiction among clients of fitness centers ; congruently to previous data , we found high rates of prevalence : forty - two percent of the regular clients were high risk - exercise addicted according to eai score
. nevertheless , despite the significant prevalence rates found in research , no specific diagnostic criteria for this condition were established . since high and intense exercise levels , such as substances of abuse , may display their effect acting on reward pathways , it would be suitable to better understand this condition , taking into account possible vulnerability factors . according to previous studies that have indirectly and separately examined narcissism and self - esteem in behavioral addictions , the present study confirms the direct and combined role of both labile self - esteem and high narcissism in the development of exercise addiction as predictive factors towards addiction , once that regular exercise initiation occurs .
although it is well recognized that regular exercise is associated with a variety of positive outcomes , the early identification of a peculiar personality profile characterized by  addictive orientation  may have a role in discriminating those vulnerable subjects who are at risk for developing exercise addiction .
furthermore , it should be borne in mind that exercise , such as other rewarding behaviors , may present a potential misuse / abuse feature beyond physical , psychical , and social benefits .
multidisciplinary trained health care providers ( physiatrists , psychologists , and psychiatrists ) should carefully identify potential overexercise conditions in order to prevent the potential risk of exercise addiction .
 the aim of this study was to assess the risk of exercise addiction ( ea ) in fitness clubs and to identify possible factors in the development of the disorder . 
 the exercise addiction inventory ( eai ) , the narcissistic personality inventory ( npi ) , and the coopersmith self - esteem inventory ( sei ) were administered to a sample of 150 consecutive gym attenders recruited in fitness centers . 
 based on eai total score , high ea risk group ( hea n = 51 ) and a low ea risk group ( lea n = 69 ) were identified . 
 hea reported significantly higher total score ( mean = 20.2 versus 14.6 ) on the npi scale and lower total score ( mean = 32.2 versus 36.4 ) on the sei scale than lea . 
 a stepwise regression analysis indicated that only narcissism and self - esteem total scores ( f = 5.66 ; df = 2 ; p = 0.006 ) were good predictors of days per week exercise . 
 the present study confirms the direct and combined role of both labile self - esteem and high narcissism in the development of exercise addiction as predictive factors towards the risk of addiction . 
 multidisciplinary trained health care providers ( physiatrists , psychologists , and psychiatrists ) should carefully identify potential overexercise conditions in order to prevent the potential risk of exercise addiction . 
1. Introduction
2. Method
3. Results
4. Discussion
5. Conclusions