the prevalence of obesity in children and adolescents is increasing world - wide , notably in developing countries . now - a - days , this problem has become one of the important concerns about general health at the global level . obesity in childhood and adolescence has different effects on mental health , including symptoms of anxiety , depression , insomnia , social isolation etc . , in turn , these conditions would have negative consequences on social relationships and learning issues . some studies documented higher prevalence of mental disorders as depression and anxiety in obese than in normal - weight individuals . in contrast , the prevalence of mental disorders is increasing in children around the world ; this can be due to the escalating trend of childhood obesity . due to the importance of mental health , it is considered as part of the world health organization global school - based health survey ( who - gshs ) . similar to most other developing countries , iran is facing double burden of nutritional disorders . some studies in iran have considered the relationship of overweight and obesity with mental disorders . although most studies in western countries found a higher prevalence of psychiatric disorders in overweight children and adolescents , but studies conducted in two cities in iran did not document the relationship of body mass index ( bmi ) with depression and anxiety in iranian students . because of diversity in the cultural and socioeconomic background in different regions of iran , it is necessary to extrapolate such investigations in different parts of the country to help in designing and implementing health promotion programs . this nationwide study aims to assess the relationship of excess weight with some mental disorders in iranian students by using the who - gshs questionnaire . this nationwide cross - sectional study was conducted as part of the third national survey of a school - based surveillance system entitled the childhood and adolescence surveillance and prevention of adult non - communicable disease - iii study . after explanation of the study aims and methods , verbal assent was obtained from students and written informed consent from their parents . this study was conducted in 2009 - 2010 among 5570 students , aged range from 10 to 18 years . they were selected by random cluster sampling from urban and rural areas of 27 provinces in iran . the questions related to the mental distress are presented in appendix i. trained health professionals conducted the physical examination under standard protocols and by using calibrated instruments . bmi was calculated as weight ( kg ) divided by height squared ( m ) . continuous variables are expressed as mean ( standard deviation [ sd ] ) and categorical variables are presented as number ( percentage ) . logistic regression analysis was used to assess the association of obesity and overweight with mental disorders . continuous variables are expressed as mean ( standard deviation [ sd ] ) and categorical variables are presented as number ( percentage ) . logistic regression analysis was used to assess the association of obesity and overweight with mental disorders . their mean sd age was 14.7 ( 2.4 ) years , without significant difference in terms of gender . table 1 shows the frequency of anxiety according to gender and bmi categories . according to their self - report , 3182 ( 58.7% ) students had anxiety , which consisted of 1417 ( 53.1% ) girls and 1765 ( 64.7% ) boys . no significant association was documented neither between overweight and anxiety ( odds ratio [ or ] : 0.86 , 95% confidence interval [ ci ] : 0.68 - 1.09 ) , nor between obesity and anxiety ( or : 1.11 , 95% ci : 0.88 - 1.40 ) . frequency of self - reported anxiety among iranian adolescents by gender and weight status : the caspian - iii study as can be seen in table 2 , 3389 ( 62.6% ) of students reported to have depression , they consisted of 1643 ( 61.1% ) girls and 1746 ( 64.3% ) boys reported to have depression . there was no significant relationship between overweight and depression ( or : 1.11 , 95% ci : 0.86 - 1.43 ) and between an obesity and depression ( or : 1.01 , 95% ci : 0.79 - 1.29 ) . the self - reported frequency of insomnia among students is presented in table 3 . it shows that 2618 ( 49.4% ) of students consisting of 1285 ( 49.1% ) girls and 1333 ( 49.7% ) boys had insomnia . no significant relationship was found neither between overweight and insomnia ( or : 1.17 , 95% ci : , 0.91 - 1.51 ) , nor between obesity and insomnia ( or : 0.91 , 95% ci : 0.71 - 1.17 ) . frequency of self - reported depression among iranian students by gender and weight status : the caspian - iii study frequency of self - reported insomnia among iranian students by gender and weight status : the caspian - iii study this study , which is the first nationwide study of its kind in iran , showed that overweight and obesity were not associated with depression , anxiety and insomnia in iranian adolescents . contrary to our findings , several studies in western countries have documented higher prevalence of these mental disorders in overweight and obese individuals . these differences could be because of social and cultural differences , especially the attitude of friends , family members and the community to obesity and obese person in various societies . similar to previous studies in iran , our findings propose that overweight and obesity in adolescence are well - accepted by the community and therefore the overweight or obese person is not under pressure by parents and peers . some previous studies have suggested that obese children , who are mocked by their friends , would experience some negative feelings including shame , isolation and depression . moreover , these studies proposed that pressure and sneap imposed by parents is increased in overweight and children and adolescents . it is also suggested that depression might lead to unhealthy behaviors and in turn might result in overweight and obesity . the current study showed that anxiety and depression are more prevalent in boys than in girls . some previous studies reported higher prevalence of such disorders in 12 - 18-year old girls and 10 - 12-year old boys . they suggested that such differences might be because of hormonal changes during puberty . in another study , depression was reported to be more prevalent in girls with 15 - 18 years of age and boys aged 10 - 14 years . further studies shall be conducted about the effects of various items including genetic , environmental , cultural , social and nutritional factors on gender differences documented by various studies about the psychiatric distress during adolescence . the present study did not find any significant difference in the prevalence of insomnia according to gender and weight status . some studies documented higher prevalence of insomnia in girls and obese individuals . in our study , the prevalence of depression and anxiety was more than a previous study in iran , however , our finding is consistent with some other studies . study limitations and strengths : the main limitations of this study are its cross - sectional setting and using self - reported data on psychiatric distress among adolescents . the main strengths are the novelty in the region , recruiting a large sample size of adolescents from diverse parts of the country , as well as using an internationally accepted questionnaire . we did not find significant relationship between excess weight and psychological distress in iranian students . this can be because of positive attitude of iranian families toward fatness in childhood and adolescence .
background : excess weight may be associated with mental distress and this relationship varies according to the socio - cultural background of different populations . 
 this study aims to assess the relationship of overweight and obesity with some psychological disorders in a nationally representative sample of iranian adolescents.methods:this nationwide study was conducted in 2009 - 2010 among 5570 students , aged 10 - 18 years , living in 27 provinces in iran . 
 data were collected by using the translated and validated questionnaire of the world health organization global school - based health survey.results:data of 5528 students ( 49.7% girls ) were complete for this study . 
 their mean age was 14.7 ( 2.4 ) years . 
 overall 7.9% of participants were overweight and 8.8% were obese . 
 58.7% of students had anxiety , without significant association of overweight ( odds ratio [ or ] : 0.86 , 95% confidence interval [ ci ] : 0.68 - 1.09 ) and obesity ( or : 1.11 , 95% ci : 0.88 - 1.40 ) with an anxiety . 
 nearly 62.6% of students reported to have depression , there was no significant relationship between overweight ( or : 1.11 , 95% ci : 0.86 - 1.43 ) obesity and ( or : 1.01 , 95% ci : 0.79 - 1.29 ) with the depression . 
 about 49.4% of students had insomnia , without significant association of overweight ( or : 1.17 , 95% ci : , 0.91 - 1.51 ) and obesity ( or : 0.91 , 95% ci : 0.71 - 1.17 ) with the insomnia.conclusions:in iranian adolescents , excess weight did not increase the risk of psychological distress . 
 this finding might be due to the positive attitude of family and peers to fatness in adolescence .