The correct answer is C. Opioid misuse is the factor most strongly associated with gabapentin misuse. When gabapentin is administered in supratherapeutic doses (therapeutic dose range is 600 - 3600 mg/d), euphoric states can be achieved. Supratherapeutic doses of gabapentin can potentiate the effects of methadone and suboxone.

Publication reference : Evoy K et al. Abuse and misuse of pregabalin and gabapetin. Drugs. 2017 Feb 1. Eprint.
Reference URL: https://www.ncbi.nlm.nih.gov/pubmed/28144823