title: The association between internet addiction and psychiatric co-morbidity: a meta-analysis.
abstract: BACKGROUND
  This study evaluates the association between Internal Addiction (IA) and psychiatric co-morbidity in the literature.
  
  
  METHODS
  Meta-analyses were conducted on cross-sectional, case-control and cohort studies which examined the relationship between IA and psychiatric co-morbidity. Selected studies were extracted from major online databases. The inclusion criteria are as follows: 1) studies conducted on human subjects; 2) IA and psychiatric co-morbidity were assessed by standardised questionnaires; and 3) availability of adequate information to calculate the effect size. Random-effects models were used to calculate the aggregate prevalence and the pooled odds ratios (OR).
  
  
  RESULTS
  Eight studies comprising 1641 patients suffering from IA and 11210 controls were included. Our analyses demonstrated a significant and positive association between IA and alcohol abuse (OR = 3.05, 95% CI = 2.14-4.37, z = 6.12, P < 0.001), attention deficit and hyperactivity (OR = 2.85, 95% CI = 2.15-3.77, z = 7.27, P < 0.001), depression (OR = 2.77, 95% CI = 2.04-3.75, z = 6.55, P < 0.001) and anxiety (OR = 2.70, 95% CI = 1.46-4.97, z = 3.18, P = 0.001).
  
  
  CONCLUSIONS
  IA is significantly associated with alcohol abuse, attention deficit and hyperactivity, depression and anxiety.
authors.forename: Roger C
authors.initials: RC
authors.lastname: Ho
authors.forename: Melvyn W B
authors.initials: MW
authors.lastname: Zhang
authors.forename: Tammy Y
authors.initials: TY
authors.lastname: Tsang
authors.forename: Anastasia H
authors.initials: AH
authors.lastname: Toh
authors.forename: Fang
authors.initials: F
authors.lastname: Pan
authors.forename: Yanxia
authors.initials: Y
authors.lastname: Lu
authors.forename: Cecilia
authors.initials: C
authors.lastname: Cheng
authors.forename: Paul S
authors.initials: PS
authors.lastname: Yip
authors.forename: Lawrence T
authors.initials: LT
authors.lastname: Lam
authors.forename: Ching-Man
authors.initials: CM
authors.lastname: Lai
authors.forename: Hiroko
authors.initials: H
authors.lastname: Watanabe
authors.affiliation: Department of Community Medicine and School of Public Health, Faculty of Medicine, University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong. kkmak@graduate.hku.hk.
authors.forename: Kwok-Kei
authors.initials: KK
authors.lastname: Mak
mesh_terms: D000437:Alcoholism / Q000453:epidemiology*; D001007:Anxiety / Q000453:epidemiology*; D001289:Attention Deficit Disorder with Hyperactivity / Q000453:epidemiology*; D016739:Behavior, Addictive / Q000453:epidemiology*; D015897:Comorbidity; D003430:Cross-Sectional Studies; D003863:Depression / Q000453:epidemiology*; D006801:Humans; D020407:Internet; D016017:Odds Ratio; D015995:Prevalence; D011795:Surveys and Questionnaires