meta-analysis of individual and environmental factors that influence people’s addiction tendencies

background in recent years, many studies have been conducted to establish the causes of people’s tendency to become addicted and researchers have also tried to determine the amount, importance and role of each individual and environmental factor. objectives with regard to the inconsistencies in previous research results, this study aims to use meta-analysis in order to integrate the results of different studies and investigate the impact of environmental and personal factors in people’s proclivity to addiction. materials and methods this meta-analysis uses the hunter and schmidt approach. for this purpose, 16 out of 32 studies which were acceptable in terms of their methodology, and had been conducted during an eight year period (2003 - 2010), were selected. a meta-analysis was conducted on the articles which had been collected using a standard checklist via; the internet, in person, telephone and e-mail, from universities and research centers across the country. after summarizing the results of the studies, effect sizes were calculated manually and combined based on a meta-analysis, and interpreted in accordance with a cohen’s table. results after data collection, results showed that the effect size of environmental factors in people’s tendency to addiction was 0.61 (p ≤ 0.00001), and the effect size of individual factors in people’s tendency to addiction was 0.45 (p ≤ 0.03). conclusions according to cohen’s table size, the effects were evaluated as average to high for the environmental factors and low to moderate for the individual factors in the tendency to become addicted.