Table 4.

Synthesis of prevalence studies.

Author	Type of population (age)	Total population	Addictive behavior	Results
Collins et al., 2011	10–17 years	1,105	Drugs, tobacco, alcohol, cannabis	The prevalence of alcohol consumption is 45%. The 35% for prescription medication, 28% for tobacco, and 17% for cannabis.
Lan and Lee, 2013	8–12 years	1,045	Internet	The 10.9% of children have an addiction to the Internet. Boys are more affected than girls. Relationship problems and depression are the most present symptoms.
Li et al., 2014	7–16 years	42 studies	Internet	The prevalence of an addiction to the Internet may vary between 2.5 and 27%. It is estimated that overall prevalence is 10%.
Li et al., 2014	7–16 years	24,013	Internet	The prevalence of Internet addiction is 6.3%. The 11.5% of elementary school students have an addiction.