4) Y-scale. To verify the concurrent validity of the first SAS,
Y-scale was added, consisting of 20 items and scored based on a 5-
point scale measuring Internet addiction, which was demonstrated
to have strong internal reliability [12,13]. As with the first SAS, the
term ‘‘Internet’’ in Y-scale was changed to ‘‘smartphone.’’ In this
study, the internal-consistency test result (Cronbach’s alpha) of Yscale
was 0.95.
5) Substance dependence and abuse diagnosis of DSMIV.
This scale consists of 11 items and was added to assess if the
participants conformed to the diagnosis of substance dependence
and abuse of DSM-IV. Seven items were included in substance
dependence, and four items in substance abuse [16].