a systematic review of literature was performed to identify the prevalence of adhd in iranian children and adolescents ( up to 18 years old ) from 1977 . inclusion criteria were : 1 ) conducting a study by generalizability of the produced data to the population of the same age ; 2 ) using valid instruments to assess adhd diagnosis or symptoms ; and 3 ) presenting a prevalence of adhd or attention deficit and / or hyperactivity symptoms . pubmed , isi web of science , psychinfo , iranpsych , iranmedex , irandoc were searched . irandoc , iranmedex and iranpsych are iranian databases of which the last one is especially for psychiatry and psychology literature . key words for search were : prevalence , rate , attention deficit , hyperactivity , adhd , behavioral problems , impulsivity , iran , tehran ( and names of other cities which have universities ) , conners rating scale , rutter rating scale , wender utah rating scale . all iranian psychiatry and psychology journals were reviewed by hand searching to identify published but not indexed articles . all the booklets of iranian psychiatry , psychology , and epidemiology congress were reviewed in hand searching . gray literature review was performed to identify final reports of research projects , desertions , and theses not published . irandoc and iranmedex were searched for final reports up to 2003 after that searched by hand searching . 80 ( 60 in farsi and 20 in english ) papers were screened in electronic and hand search by title and abstract ; of which 64 ( 45 in farsi and 19 in english ) were rejected as they were either unrelated or repeated in some sources . in the gray literature search , 57 final reports were screened by abstract ; of which 50 were rejected or deleted . it should be noted that we deleted some of the reports as some universities refused to give us the full text of the final reports . quality assessment was performed on full texts of 13 papers and 7 final reports which were approved in the last stage . for quality assessment quality assessment checklist for prevalence studies  which assesses sampling , measurement and analysis method of studies : does the study design yield a sample of respondents representative of defined target group , do the survey instruments yield reliable and valid measures of adhd and other key concepts ( also for translated version ) , and were special features of the sampling design accounted for in the analysis or subgroups prevalence rates reported ? they reviewed each article and report , and if they both approved an article or a report , we accepted the material ; but if one of them rejected the material , a third person reviewed it again . in quality assessment , 10 papers and 5 final reports were accepted . some papers were excluded due to not reporting the prevalence or lack of randomization in sampling . due to so many heterogeneities in instruments and in the rate of reported prevalence , we did not conduct analysis , and described the results in tables and graphs . pubmed , isi web of science , psychinfo , iranpsych , iranmedex , irandoc were searched . irandoc , iranmedex and iranpsych are iranian databases of which the last one is especially for psychiatry and psychology literature . key words for search were : prevalence , rate , attention deficit , hyperactivity , adhd , behavioral problems , impulsivity , iran , tehran ( and names of other cities which have universities ) , conners rating scale , rutter rating scale , wender utah rating scale . all iranian psychiatry and psychology journals were reviewed by hand searching to identify published but not indexed articles . all the booklets of iranian psychiatry , psychology , and epidemiology congress were reviewed in hand searching . gray literature review was performed to identify final reports of research projects , desertions , and theses not published . irandoc and iranmedex were searched for final reports up to 2003 after that searched by hand searching . 80 ( 60 in farsi and 20 in english ) papers were screened in electronic and hand search by title and abstract ; of which 64 ( 45 in farsi and 19 in english ) were rejected as they were either unrelated or repeated in some sources . in the gray literature search , 57 final reports were screened by abstract ; of which 50 were rejected or deleted . it should be noted that we deleted some of the reports as some universities refused to give us the full text of the final reports . quality assessment was performed on full texts of 13 papers and 7 final reports which were approved in the last stage . for quality assessment , we used quality assessment checklist for prevalence studies  which assesses sampling , measurement and analysis method of studies : does the study design yield a sample of respondents representative of defined target group , do the survey instruments yield reliable and valid measures of adhd and other key concepts ( also for translated version ) , and were special features of the sampling design accounted for in the analysis or subgroups prevalence rates reported ? they reviewed each article and report , and if they both approved an article or a report , we accepted the material ; but if one of them rejected the material , a third person reviewed it again . in quality assessment , 10 papers and 5 final reports were accepted . some papers were excluded due to not reporting the prevalence or lack of randomization in sampling . due to so many heterogeneities in instruments and in the rate of reported prevalence , we did not conduct analysis , and described the results in tables and graphs . however , 3 studies have been conducted on preschool - aged children and only one study addressed university students . the instruments of studies were conners ( teacher and parents ) , rutter ( teacher and parents ) , and csi-4 ( teacher and parents ) questionnaire . conners for parents has 48 questions and its cut off point is 15(chronbach 's alpha:%91 ) . conner for teachers has 28 questions and its cut off point is 15(chronbach 's alpha:%96 ) . characteristics of studies included in the analyses reliability of rutter test by test - retest is % 90 and its validity is % 76.7(p=0.001 ) . reliability of csi-4 for parents is % 87 and for teachers is % 89 and its cut off is 6 . it has facial validity and its sensitivity is % 62 with the specificity of%83.it should be noted that conners , rutter and csi-4 calculate adhd according to their scoring system . what is obtained from these scales tehran has the most prevalence rate of adhd , while sanandaj has the least prevalence . it can be related to more social stigma and less access to psychiatric consultation in cities like sanandaj . figure 2 shows the prevalence of hyperactive type of adhd in girls and boys . the prevalence of hyperactive type of adhd in girls and boys the prevalence of inattentive type of adhd in girls and boys . we have conducted a systematic review of studies addressing prevalence rates of adhd in iran . our results should be interpreted with caution because of the large variability found in all the conducted analyses . probably the different prevalence rates across studies could be accounted for by different methodologies ( 8 , 13 , 14 ) . methodological features were coded for each study , including sample size , response rate , information source ( e.g. , parents , teachers , children ) , and whether diagnosis followed the dsm or not . according to dsm , it is possible to diagnose a child who shows symptoms in only one dimension . some impairing symptoms , but not all , must be shown at home and at school . unfortunately , many of iranian studies have only used rating scales to diagnose adhd in the children . moreover , different rating scales have been used by such as conners , rutter and csi-4 . there was not any representative community sample in our studies , and this affects the reported prevalence rate . an analysis of epidemiological studies in the usa found that community samples gave higher prevalence rates than school samples ( mean prevalence : 10.3% for community samples vs. 6.9% for school samples ) ( 15 , 16 ) . it is generally agreed that the prevalence of adhd is significantly higher in boys than in girls , especially in children . thus , the ratio of males to females in the sample population can affect the apparent prevalence and may need to be taken into account . for example , three studies have shown decreases in the prevalence with increasing age over the age range 10 - 20 years ( 17 ) , 8 - 15 years ( 18 ) , and 6 - 14 years ( 19 ) . thus , even within studies conducted on children , the age range of the sample is likely to affect the apparent prevalence . most of the studies in our country have been conducted in school - aged children . although analysis were done in similar age groups , but the heterogeneity did not decrease . supporting this conclusion , a multisite trial study reported that using a uniform diagnostic protocol yields adhd patients who are highly similar across clinics in africa , australia , europe , and north america ( 20 ) . it is difficult to make exact comparisons between studies because the estimated prevalence is highly influenced by the means of assessment and the type of sample recruited . it is necessary to take these factors into account when comparing data from different studies . one limitation of the literature we reviewed is the reliance of many studies on rating scale measures rather than interviews with patients and parents . unlike rating scale methods , interview - based procedures come close to reproduce the results one might expect from a clinical evaluation and are better able to incorporate the impairment and pervasiveness criteria of the dsm diagnoses of adhd . as discussed by hartman et al ( 21 ) , it is possible that improved operational symptoms could lead to increased measurement precision and a better assessment of the validity of diagnostic categories . the other limitation was that some studies had reported only the mean score of the indexes . theses figures could not be accounted because it was not clear how many subjects were above the cutoff point .
objectiveattention - deficit / hyperactivity disorder ( adhd ) is the most common neurobehavioral disorder of childhood . 
 children with adhd may experience significant functional problems . our objective was to examine the prevalence of adhd and its subtypes in iran.methodspubmed , 
 isi web of science , psychinfo , iranpsych , iranmedex , irandoc were searched . 
 irandoc , iranmedex and iranpsych are iranian databases of which the last one is especially for psychiatry and psychology literature.inclusion criteria were : conducting studies by random sampling , using valid instruments to assess adhd diagnosis or symptoms , and presenting a prevalence of adhd or attention deficit and / or hyperactivity symptoms.resultsafter quality assessment , 16 studies were accepted . 
 their estimation of prevalence was different as different scales were used . 
 hyperactive type was more prevalent in boys , and inattentive type was more prevalent in girls.conclusionbeing aware of the epidemiology of adhd in iran helps us to make improvements in planning the allocation of funds for mental health services . using one instrument in studying the prevalence of adhd in a population may lead to more precise estimations .