Table 2.

The characteristics of including papers and the finding and extracted results

First author, date of publication, country	Type of study	Characteristics of participants (age, sample size, gender)	Time spent consuming media and reported frequency of violent content	Type of aggressive behaviors or violence and type of media	Main result	Finding
Marina Verlinden, 2014, Netherlands[21]	population-based cohort	5389, boy and girl Teacher report of bullying involvement (n=3423) mean=6.8 years±3.03 months. Peer/self-report of bullying involvement (n=1176) mean=7.6 years±8.95 months	Low= <1 hour, high>1 h, mid-low and mid high=the probabilities of watching>1 h of TV daily increased between ages 2-4 and were considerably lower at age 5 years. In Teacher report of bullying involvement group: 42% mid-low and in Peer/self-report of bullying involvement group 44.2% mid-low	Bully, Victim/TV	High television exposure class was associated with elevated risks of bullying and victimization. Also, in both teacher- and child-reported data, children in the high television exposure class were more likely to be a bully-victim (OR=2.11, 95% CI: 1.42-3.13 and OR=3.68, 95% CI: 1.75-7.74 respectively).	The association between television viewing time through ages 2-5 and bullying involvement in early elementary school is confounded by maternal and child socio-demographic characteristics.
Jennifer A. Manganello, 2009, US[20]	prospective cohort study	3128 mothers, boy and girl 0.30 to 50 months (mean, 36 months)	About two-thirds (65%) of mothers reported that their index child watched more than 2 h of TV per day (mean, 3.2 [SD, 2.3]; median, 3; range, 0-24 h). After subtracting direct child TV exposure, there was an average of 5.2 hours of additional household TV use on a typical day (SD, 5.7; median, 3; range, 0-24 h)	Aggressive behavior/TV	Direct child TV exposure (β = 0.16, P 0.001) and household TV use (β = 0.09, P 0.001) were also significantly associated with childhood aggression, even when controlling for other factors.	Three-year-old children exposed to more TV, both directly and indirectly, are at increased risk for exhibiting aggressive behavior. Further research is essential to determine whether pediatric recommendations concerning TV and children should include limits for general household TV use
Maxine M. Denniston, 2011, GA[19]	cross-sectional	14041 students. in grades nine through 12	> 3 hours/day	Interpersonal violence, alcohol and drug use/watching TV and playing computer or video games	Overall, 35.4% (95% CI=33.1%-37.7%) of students reported frequent television (TV) use and 24.9% (95% CI=22.9%-27.0%) reported frequent computer/video game use. A number of risk behaviors, including involvement in physical fights and initiation of alcohol use before age 13, were significantly associated with frequent TV use or frequent computer/video game use, even after controlling for sex, race/ethnicity and grade.	Findings highlight the need for additional research to better understand the mechanisms by which electronic media exposure and health-risk behaviors are associated and for the development of strategies that seek to understand how the content and context (e.g., watching with peers, having computer in common area) of media use influence risk behaviors among youth
ELIF N ÖZMERT, 2011, Turkey[22]	cross-sectional survey	581 (332 female, 249 male). 13.5±0.7 (12-16 years).	The mean duration of TV viewing was 2.32±1.77 hours/day according to parents and 2.08±1.41 hours/day according to self-report	Aggressive behavior/TV	The linear regression analysis revealed a statistically significant relation between socioeconomic status (P=0.019) and aggressive behavior score of CBCL (P=0.016) and parent reported TV viewing hours. Self-reported TV viewing for more than 2 h was significantly associated with social problem score (OR 1.17; 95% CI: 1.016-1.349; P=0.030) and having a TV in bedroom (OR: 1.70; 95% CI: 1.065-2.731, P=0.026).	The linear regression analysis for family reported TV viewing hours revealed significance for socio-economic status (P=0.019) and aggressive problem score (P=0.016). Binary logistic analysis for self-reported TV viewing for more than 2 hours was associated significantly with social problem score (OR 1.17, 95 % CI 1.016-1.349; P=0.030) and having a TV in bedroom (OR 1.706, 95% CI: 1.065-2.731, P=0.026).
Ian Janssen, 2012, Canada[23]	prospective cohort	9,672 Canadian youth in grades 6-10 and a 1-year longitudinal sample of 1,861 youth in grades 9-10.	The median weekly screen time values were 17 h for television, 9 h for computer, and 7 h for video games in the cross-sectional sample. The corresponding values were 16 h, 14 h, and 4.5 h for the longitudinal sample.	physical fights and/or episodes of physical bullying/watching television, playing video games, and using a computer	In the cross-sectional sample, computer use was associated with violence independent of television and video game use. Video game use was associated with violence in girls but not boys. Television use was not associated with violence after controlling for the other screen time measures. In the longitudinal sample, video game use was a significant predictor of violence after controlling for the other screen time measures.	Computer and video game use were the screen time measures most strongly related to violence in this large sample of youth.
EMIL G. M. 1997, Netherlands[24]	cross-sectional survey	346 children consisted of 175 girls and 171 boys 0.7th and 8th grade from seven elementary schools mean=11.5 years	About 70% of the children played videogames at least once in the week concerned. Only 16 children (5%) had played videogames every day of the week. Of the children in our study, 3% indicated that their time playing videogames averages more than 2 hr per day. About 6% played between 1 and 2 hr per day, 14% played between 30 min and 1 hr per day, and 48% played less than 30 min per day on average	sticking out their tongues, telling lies, and fighting/video games	There was no significant relationship between the amount of time children spent on videogames and aggressive behavior. A negative relationship between time spent playing videogames and social behavior was found; however, this relationship did not appear in separate analyses for boys and girls	there was no significant relationship between judgments on the amount of aggressive behavior and the amount of time a child spent playing videogames
S. Liliana Escobar-Chaves, 2002, USA.[25]	cross-sectional survey	5,831 students 49.9%males and 50.1% females’. from 11 to 16 years mean age: 13.2.	Only 5% of the students played video games four or more hours during the week, and 9% played four or more hours during the weekend. Both during the weekdays and the weekends, boys were four times more likely than girls to play four or more hours of video games.	teasing, pushing, name-calling, hitting, encouraging students to fight, kicking, threatening to hurt or hit, and getting angry easily/video games	A linear relationship was observed between the time spent playing video games and aggression scores. Higher aggression scores were significantly associated with heavier video playing for boys and girls (P<0.0001). The more students played video games, the more they fought at school (P<0.0001).	Higher aggression scores were significantly associated with heavier weekday video game playing (F (4, 5103) = 73.6, P<0.0001) as well as with heavier weekend video game playing (F (4, 5083) = 48.5, P<0.0001).
Mukaddes Demirok, 2012, Turkey[26]	cross-sectional survey	Four hundred : 231 male and 169 female students. ages of 15-18 (M=16.2, SD=0.90).	Thirty-one per cent (n=131) played every day, while 43% (n=180) played 3-4 days a week. Only 11.8% of students (n=49) played one day a week, 5.3% (n=23) one day a fortnight, and 4% (n=17) less than once a fortnight.	Expressing anger. These dimensions include ‘Anger Control’ (8 items, α = 0.87), ‘Anger-Out’ (8 items, α = 0.91) and ‘Anger-In’ (8 items, α = 0.90)./played computer games	The results showed that students who played computer games for 30 minutes a day reported a lower level of trait anger compared to others. They also reported less external aggression.	It was found that students who played computer games for 2-3 h a day scored higher on expressed anger than those who played for less than half an hour a day.
Cheryl K. Olson, 2009, USA[27]	cross-sectional survey	1069 male and females/8th grade	not reported	Delinquent behaviors (damaging property for fun, stealing from a store, skipping school, or getting in trouble with the police) and physical aggression (hitting or beating up someone, or getting in physical fights)/‘‘computer games, video games and handheld games	Even after controlling for a variety of possible confounding variables, exposure to M-rated games remained a strongly significant predictor of engaging in bullying and physical aggression. Further, this relationship was dose-related: each additional day-per-week category of exposure to M-rated games increased the probability of bullying behavior by 45%.	M-rated game dose predicted greater risk for bullying (P<0.01) and physical fights (P<0.001), but not for delinquent behaviors or being a victim of bullies. When analyzed separately, these associations became weaker for boys and stronger for girls.
Jeffrey G. Johnson, 2002, USA[28]	a community-based longitudinal investigation	707 families with a child (51% male). ages of 1 and 10, The mean age of the youths was 5.8 (SD=3) in 1975, 13.8 (SD=3) in 1983, 16.2 (SD=3) in 1985-86, 22.1 (SD=3) in 1991-93, and 30.0 (SD=3) in 2000.	from <1 h to 1 to 3 hours per day of television viewing	Assault or physical fights resulting in injury, Robbery, threats to injure someone, or weapon used to commit a crime, Any aggressive act against another person/Television viewing	Aggressive behaviors at mean age 14 were not associated with subsequent television viewing after the covariates were controlled statistically. However, youths who committed assaults or participated in fights resulting in injury at mean age 16 spent significantly more time watching television at mean age 22 than did the remainder of the youths in the sample (2=10.94; df=2; P=0.004).	There was a significant association between the amount of time spent watching television during adolescence and early adulthood and the likelihood of subsequent aggressive acts against others.
Oene Wiegman, 1998, Netherlands[29]	cross-sectional	278 (144 girls and 134 boys). seventh and eighth :average age children was 11.5	About 70 per cent of the children indicated that they played video games at least once in the week concerned. Only 17 children (6 per cent) had been playing video games every day of the week.	sticking out their tongue, telling lies and fighting/playing video games	No significant difference was found between the group of heavy players, moderate players and non-players.	No significant relationship was found between video game use in general and aggressive behavior.
Linda Heath, 1986, USA[30]	case - control	93 males (48 males incarcerated for violent crimes and 45 non incarcerated). retrospective television viewing: 8, 10, and 12 years, the time of our interviews: between 18 and 25 years of age.	Inmates reported viewing an average of ten violent television programs a week, and the comparison sample of respondents reported viewing an average of eight violent shows a week. Inmates watched a mean of 33 programs per week, while the comparison group mean was 28 programs per week. The pattern of results in regard to nonviolent programming was also in this direction, with inmates reporting watching 23 programs per week, compared with 19 programs per week for the control group.	Murder, rape, robbery , sexual or physical assault/TV	Results show that the extent of a respondent’s reported television viewing was not, in and of itself, predictive of violent criminal acts.	The television exposure variables (total viewing, violence viewing, and nonviolence viewing) enter all of the discriminant equations, but none of the equations provides particularly strong predictions of violent behavior.
MARK I. SINGER, 1998, USA[31]	cross-sectional	2245 students, (50.9%were boys). mean=11±1.8	Most students (66%) watched 3 or more hours of television per day. In addition, more than one third (36%) of students reported watching 5 or more hours of television per day.	threatening others, slapping, punching, hitting beating-up, attacking someone with a knife/TV	A linear trend was noted beginning at 1 to 2 hours, with a sharp increase between 5 to 6 hours and more than 6 hours of television viewing per day. Categories of 5 to 6 hours and lower were collapsed into a single category (0) and a point biserial correlation was calculated, resulting in a coefficient of 0.19 (P<0.00l).	children who report watching greater amounts of television per day will report higher levels of violent behaviors than children who report watching lesser amounts of television per day.
Vincent Busch, 2013, Netherlands.[32]	cross-sectional survey	(N=2425). Mean in years: Boys=13.7, Girls=13.9. Total=13.8. (range 11-18 years).	Watching TV (>14h/week):boys=271 (25.9%), girls=324 (24.5%), total 595 (25.1%). Internet Use>14/week):boys=288 (27.3%), girls=340 (25.5%), total=628 (26.3%). Video Game Playing (>14/week):boys 48 (4.6%), girls=8 (0.6%), total=56 (2.3)	Bullying/Watching TV, Internet Use, Video Game Playing	Screen time was associated with bullying, being bullied.	Screen time was of significant importance to adolescent health. Behavioral interrelatedness caused significant confounding in the studied relations when behaviors were analyzed separately compared to a multi-behavioral approach, which speaks for more multi-behavioral analyses in future studies.
RoyaKelishadi, 2015, Iran[33]	cross-sectional	13,486 children and adolescents (50.8% boys ). aged 6-18 years, Mean (SD) age was 12.47 (3.36) years	(>2 hrs/≤2 hrs)	physical fights, bullying and being bullied/Watching TV, Using a computer, Screen activity	The risk of physical fighting and quarrels increased by 29% (OR 1.29, 95% CI 1.19-1.40) with watching TV for 0.2 hr/day, by 38% (OR 1.38, 95% CI 1.21-1.57) with leisure time computer work of 0.2 h/day, and by 42% (OR 1.42, 95% CI 1.28-1.58) with the total screen time of 0.2 hr/day. Watching TV or leisure time spent on a computer or total screen time of 0.2 hr/day increased the risk of bullying by 30% (OR 1.30, 95% CI 1.18-1.43), 57% (1.57, 95% CI 1.34-1.85) and 62% (OR 1.62, 95% CI 1.43-1.83).	Prolonged leisure time spent on screen activities is associated with violent and aggressive behavior in children and adolescents. In addition to the duration of screen time, the association is likely to be explained also by the media content.
Lindsay A, 2013, New Zealand[34]	cross-sectional	5 to 15 years	more than 1 to 2 hours of television each day	antisocial behavior/TV	Excessive television viewing in childhood and adolescence is associated with increased antisocial behavior in early adulthood. The findings are consistent with a causal association and support the American Academy of Pediatrics recommendation that children should watch no more than 1 to 2 h of television each day.	Young adults who had spent more time watching television during childhood and adolescence were significantly more likely to have a criminal conviction, a diagnosis of antisocial personality disorder, and more aggressive personality traits compared with those who viewed less television.
Kamila B, 2007, Maryland[35]	Prospective longitudinal study	2707 children whose mothers completed telephone interviews at both 30 to 33 months and 5.5 years and reported television exposure at both time points. at 30-33 months and 5.5 years	Sixteen percent of parents reported that their child watched 2 hours of television daily at 30 to 33 months only, 15% reported 2 hours of television daily at 5.5 years only, and 20% reported 2 hours of television daily at both times.	aggressive behavior/Television viewing daily, including videos, and having a television in the child’s bedroom	Sustained exposure is a risk factor for behavioral problems, whereas early exposure that is subsequently reduced presents no additional risk.	Sixteen percent of parents reported their child watched 2 hours of television daily at 30 to 33 months only (early exposure) and 15% reported 2 hours of television daily at 5.5 years only (concurrent exposure). A higher percentage of parents, 20%, reported that their child watched 2 hours of television daily at both times (sustained exposure).
Linda S. Pagani, 2010, Michigan[36]	Prospective longitudinal study	1314 (of 2120) children. Fourth grade (mean [SD] age, 121.83 [3.11] months).	Television exposure at 29 months was a mean (SD) of 8.82 (6.17) h for the entire week and rose to 14.85 (8.05) h per week by 53 months	Physical aggression/Television viewing	every additional hour of television exposure at 29 months corresponded to10% unit increases in victimization by classmates (95% CI, 0.01 to 0.05)	every additional hour of television exposure at 29 months corresponded to10% unit increases in victimization by classmates (95% CI, 0.01 to 0.05)
Frederick J. Zimmerman, 2005, Washington[37]	National Longitudinal Survey	1266 children (Female, % 48.7).9.19±1.66 years.	Television viewing at age 4 years, h/d=3.47±3.92	Bullies/Television viewing	Each hour of television viewed per day at age 4 years was associated with a significant odds ratio of 1.06 (95% confidence interval, 1.02-1.11) for subsequent bullying.	Exposure to television, has a significant impact on bullying in grade school.