Compulsive Internet Use Scale

"The Compulsive Internet Use Scale
(CIUS). The CIUS was designed to measure severity of CIU
and originates from an analysis of the criteria for Dependence
and Obsessive-Compulsive disorder as found in the
DSM-IV,9 the literature on behavioral addictions, and from
qualitative research among self-declared Internet addicts."

This was a recently published instrument that I may use: here is a link (it's a chapter in a full book, which is free)