although studies on the effects of children s use of computers are still undetermined , some initial studies showed positive and negative effects in this regard .
children commonly use computers for playing games , completing school assignments , sending / receiving e - mails , and connecting to the internet .
this may sometimes interfere with other activities such as homework or normal social interchange ( 1 ) .
studies showed that internet addiction positively correlated with depression , novelty seeking , harm avoidance , and reward dependence . on the other hand , internet addiction negatively correlated with persistence , self - directness , cooperativeness , and self - transcendence .
in several studies it was demonstrated that significant factors affecting internet addiction were depression , gender , novelty seeking , and self - transcendence ( 2 , 3 ) .
computer game addiction is excessive or compulsive use of the internet , computer , and video games that may interfere with daily life .
it is not clear whether internet and video game playing meets the diagnostic criteria of diagnostic and statistical manual of mental disorders , 4 edition ( dsm - iv ) ( 4 ) .
previous studies about internet addiction have investigated several associated psychological variables such as shyness , loneliness , self - consciousness , anxiety , depression , and interpersonal relations ( 5 ) .
some studies revealed a significant association between internet addiction and depressive symptoms in adolescents and high school students .
many investigations suggest the necessity of the evaluation of the potential underlying depression in the treatment of internet - addicted adolescents ( 6 ) . moreover , the level of internet addiction correlated positively with the level of depression and suicidal ideation among high school students . based upon several studies ,
there were significant positive correlations among internet addiction , depression , and suicidal ideation in adolescents ( 7 ) .
kim et al . showed that the levels of depression and suicide ideation were highest in the internet - addicts group than other students .
they advised future studies to investigate the direct relationship between psychological health problems and internet dependency ( 8) . in this study we tried to investigate the prevalence of internet , computer games , and dvd and video addiction among high school students in southern iran , shiraz , and its relation to depression and anxiety
during the years 2008 and 2009 and in a cross - sectional study 1020 high school students ( males and females ) were selected randomly by area and cluster sampling from different areas of shiraz in southern iran .
an informed consent was received from each participant and they were assured of the confidentiality of the data .  
the students were given a full explanation of the reasons for the implementation of the study and were informed that their responses would be confidential .
they were asked to express their personal comments and recommendations at the end of the interview .
special attention was paid to ensure that the students clearly understand the instructions of the interview .
in addition , they were asked not to say their name or student number in order to encourage them to provide more open and honest answers .
demographic data ( age , sex , and economic status according to income of the family ) , duration of internet usage , computer games playing , tv and satellite watching , dvd and video cd usage , and the reasons of the usages were asked at the interviews .  
the students were interviewed for addiction , generalized anxiety disorder , and major depressive disorder according to the dsm - iv criteria . 

mild depression : decreased mood , presence of anxiety symptoms , and increased symptoms in the afternoon , without suicidal idea . 
 moderate depression : decreased activity , depressed mood , agitation , decreased energy , and decreased concentration , sense of guilt , hypochondriacs , sleep disturbance , depersonalization symptoms , decreased appetite , and decreased sexual activities .  

dependent : dysfunctional , and withdrawal symptoms ( restlessness , anxiety , decreased concentration , insomnia , irritability , fatigue , and craving ) after discontinuing . 

the obtained data were analyzed using descriptive indices and the analytic methods of the chi - squared and pearson regression .
the data were analyzed with statistical package for social sciences ( spss ) for windows15.0 ( chicago , il .
277 students ( 27.2% ) were in the first year of high school , 242 ( 23.7% ) were students of the second year , and 501 ( 49.1% ) were in the third year of high school .
140 students ( 13.7% ) had low economic status ( defined as family monthly income of less than 3000000 rials income ) , 807 ( 79.1% ) had moderate economic status ( 3000000 - 1000000 rials income per month ) , and 62 ( 6.1% ) had high economic status ( more than 10,000,000 rials income per month ) . 

table 1 shows the prevalence of depression and anxiety among students according to sex , economic state , and internet , computer , or dvd usage , and history of medical disease .  
13 students ( 1.3% ) were computer games abusers , and 634 students ( 85% ) reported playing computer games for amusement .
215 ( 21.1% ) of student did not use dvd or video cd . 1 student ( 0.1% )
was dvd or video cd abuser , and 576 students ( 77.7% ) reported using dvd or video cd for amusement . 22 ( 2.2% ) students did not watch tv or satellite ,
4 students were abusers , and 190 ( 18.6% ) students were dependent to tv or satellite .
455 ( 53.6% ) students reported watching tv or satellite for film and football , and 306 ( 36.2% ) for amusement .
94 students ( 9.2% ) had medical problems , and 71 ( 7% ) used some medications regularly .
prevalence of anxiety and depression were significantly higher in females ( p < 0.05 ) .
the prevalence of anxiety and depression was significantly lower in students of the third year compared to other grades ( p < 0.05 ) .
the prevalence of anxiety was significantly higher in students with lower family monthly income status ( p < 0.05 ) .
the prevalence of depression was significantly higher in students with lower economic status ( p < 0.05 ) .
the prevalence of depression was significantly higher in students who were internet abusers or dependents ( p < 0.05 ) , but we did not detect a significant relation between anxiety and internet usage .  
the prevalence of anxiety was significantly higher in the students who used the internet for chatting , amusement ( such as downloading music , films , and pictures ) , and reading the news compared to the students who used the internet for other reasons ( p < 0.05 ) .
there was no significant correlation between depression and reason of internet use among the students .
the prevalence of anxiety and depression were significantly higher in students who were computer games abusers or dependents ( p < 0.05 ) .
the prevalence of anxiety and depression did not show a relationship with the reason of playing computer games .
the prevalence of anxiety was significantly higher in students who were dvd or video cd dependents(p < 0.05 ) .
the prevalence of depression did not relate to the level of dvd or video cd use .
students who used dvd or video cd for resting had higher levels of anxiety and depression ( p < 0.05 ) .
the prevalence of depression and anxiety did not relate to the usage of tv or satellite ( p < 0.05 ) .
students who watched tv or satellite for film , football , and music had lower levels of anxiety ( p < 0.05 ) . students who watched tv or satellite for film and football had lower levels of depression ( p < 0.05 ) .
the students who used some medications regularly or had medical problems had higher rates of depression and anxiety ( p < 0.05 ) .
the problem of excessive computer and internet usage is increasing more rapidly and it can occur together with other kinds of addiction .
the causes of internet addiction do not have only habitual bases , but also demographic and socioeconomic aspects .
the behaviors related to internet addiction may be a symptom of depressive disorders in adolescents ( 9 - 11 ) .
prevalence of depression and anxiety among students according to sex , economic state , and internet , computer , or dvd usage , and history of medical disease batthyany et al . reported excessive computer playing and internet usage corresponding to addictive behaviors were found in 12.3% of the adolescents in austria ( 12 ) .
. showed the rate of internet addiction in the high school students to be about 7% which was more prevalent among males ( 13 ) .
hur in study on korean adolescents reported significant correlations among internet addiction , depression , and suicidal ideation ( 14 ) .
ha et al . found that almost one third of subjects in their study diagnosed as internet addicts had a significant level of depressive symptoms that required psychiatric intervention ( 15 ) .
these users use the internet to such an extent that it interferes with their academic studies and they are very much preoccupied with it .
it is still very much a matter of debate whether internet addiction is a distinct disorder or a behavioral problem secondary to another disorder .
suggested that internet communication with people can alleviate depression , at least among socially isolated and moderately depressed populations such as college students ( 11 ) .
they added that the behaviors related to internet addiction may be a symptom of depressive disorders in adolescents .  
educationists and parents should try to understand the root causes of any isolation in the youth .
it is alarming that excessive internet users are more likely to report having felt sad or depressed most of the days in the past year .
they opined that the possible co - morbidity of major depressive disorder among internet - dependent adolescents could be explained by the internalizing tendency of the adolescents .
internalized depressive adolescents can escape from the reality or problems of the real world by losing themselves in the cyber world .
purposeful activities on the internet , which are focused , for example on academics - related research or discussing a project online , can be completed in relatively shorter periods of time through good planning .
however , use of the internet for entertainment may not have a time limit and some activities like multi - player games can be highly compulsive .
parental rules in such situations can set the limit , and thereby reduce excessive use and limit negative outcomes .
the rate of internet , computer games , and dvd addiction in our study were significantly lower than reports from other parts of the world .
the prevalence of anxiety was significantly higher in students who did not use the internet .
these abnormal results may be due to lower economic states among the students who did not use the internet .  
the prevalence of anxiety was significantly higher in the students who used internet for chat , amusement , and news .
similar to other studies , the prevalence of anxiety and depression was significantly higher in students who were computer game abusers or dependents , although it did not have any relation with the reason of playing of the computer games .  
for example , ha et al . reported that one third of subjects in their study diagnosed as internet addicts had a significant level of depressive symptoms that required psychiatric intervention ( 15 ) .
while internet addiction is a new phenomenon , it has already become a subject of numerous studies . on the other hand ,
it is a very complicated problem and it is difficult to state whether it is more accurate to treat the problem totally as an addiction or not ( 15 - 17 ) . in summary , it can be concluded that the results presented in this study are for the most part in accordance with those of other authors and other studies on this subject .
some differences could be the result of different conditions , instruments , and differences in the number and structure of the studied group .
ja conceived and designed the evaluation and helped to draft the manuscript and its revision and re - evaluated the clinical data .
aa participated in the evaluation and collection of the clinical data , and helped to draft the manuscript .
agh participated in conceiving and designing the evaluation and helped to draft the manuscript and re - evaluated the clinical data .
mkh , zkh , and zgh participated in the evaluation and collected the clinical data .

 declaration of interest : none . 
 citation : ahmadi j , amiri a , ghanizadeh a , khademalhosseini m , khademalhosseini z , gholami z , et al
. prevalence of addiction to the internet , computer games , dvd and video and its relationship to anxiety and depression in a sample of iranian high school students .
 
 objective : the objective of this study was to assess the prevalence of addiction to the internet , computer games , dvd , and video and its relationship to anxiety and depression in a sample of iranian high school students . 
 
 methods : in this cross - sectional study 1020 high school students ( males and females ) were selected randomly from different areas of shiraz city in southern iran . 
 they were interviewed according to the diagnostic and statistical manual of mental disorders , 4th ed ( dsm - iv ) criteria . 
 
 results : about 50% of the students were females , 277 students ( 27.2% ) were studying in the first year of high school , 242 ( 23.7% ) were in the second year , and others in the third year . 
 the prevalence of anxiety was significantly higher in females than in males ( p < 0.05 ) . 
 the prevalence of anxiety was lower among students of the third year ( p < 0.05 ) . 
 the prevalence of depression was significantly higher in students with lower economic status defined as family monthly income . 
 internet dependence was seen only in 5 students . 
 the prevalence of anxiety was significantly higher in the students who used internet for chatting , amusement , and reading news ( p < 0.05 ) . 
 the prevalence of anxiety was significantly higher in students who were dvd or video cd dependents ( p < 0.05 ) . 
 the students who used especial drugs or had especial diseases had higher rates of depression and anxiety ( p < 0.05 ) . 
 
 conclusion : internet addiction may cause depression and anxiety in high school students . 
 it seems necessary to develop an internet addiction prevention program for adolescents taking into account the psychological factors such as depression and internet use habits . 
Introduction
Materials and Methods
Results
Discussion
Conclusion
Authors' contributions
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