The “Alcohol, Smoking and Substance Involvement
Screening Test” (ASSIST-WHO, version 3.1) criteria were included
in the questionnaire. The 8-item ASSIST-WHO obtains
information concerning drug use across the lifetime and over
the last 3 months and also obtains information concerning
drug-related problems over the last 3 months. Furthermore,
the ASSIST-WHO indicates the level of risk associated with a
respondent’s substance use and whether their use is hazardous
and likely to cause harm. The score obtained for each
assessed substance is classified into the following risk categories: “low” (occasional or non-problematic use), “moderate”
(regular use that warrants a brief intervention) or “high” (frequent
and high-risk use that warrants the referral of the user
to a specialized alcohol/drug treatment program) . Mid-range
scores on the ASSIST-WHO suggest hazardous substance use
(i.e., “moderate risk”), and higher scores suggest substance
dependence (i.e., “high risk”); however, the ASSIST-WHO is
a screening tool that lacks diagnostic criteria.20 In this study,
as the frequencies of high-risk ASSIST-WHO scores were low
for all of the drugs investigated, moderate- and high-risk
ASSIST-WHO scores were jointly assessed to describe drug
use that was hazardous.