Objective: To compare the socio-demographic and clinical data of inmates using gabapentin for medicinal purposes and those abusing the drug. Methods: The study included inmates of the Konya E-Type Prison who used gabapentin between June 2012 and December 2014 and were admitted to the prison polyclinic. The participants were divided into two groups; those using gabapentin due to existing symptoms without any labeled indication (Group 1), and those using the medication due to disorders with labeled indications (Group 2). Both groups were investigated in terms of drug addiction, drug abuse, and gabapentin abuse according to the Diagnostic and Statistical Manual-Text Revision (DSM IV-TR). Results: Nearly all inmates (n=21) using gabapentin with off-label indications (Group 1) reported using it due to muscle pain, neuropathic pain, sleep disorder, signs of anxiety, sweating, trembling, and nausea-vomiting, whereas those using gabapentin with labeled indications (Group 2) reported using it because of their diseases, such as diabetic neuropathy and epilepsy. Alcohol/substance abuse was found higher among the first-degree relatives of those using gabapentin with off-label indications (P < 0.001). The rates of substance dependence (n=10) and substance abuse (n=13) were significantly higher in Group 1 than in Group 2 (P < 0.001). Conclusion: The inmates who were diagnosed as having drug addiction and substance abuse according to the DSM-IV-TR used gabapentin after entering prison to prevent opioid withdrawal symptoms.