From a new meta-analysis of gabapentin misuse:
Gabapentin has been presumed to have no abuse potential historically [19-23]; however, this review reports evidence to the contrary. Of the 11 population-based studies and 23 case reports included here, nearly one-third report gabapentin misuse/abuse for recreational purposes and epidemiological studies from the United States and United Kingdom estimate abuse rates between 40 and 65% just among individuals with a gabapentin prescription. Studies from the United Kingdom indicate that gabapentin has developed a prominent place as a drug of abuse; in Scottish prisons, gabapentin is among the top-requested prescription drugs of abuse . However, the rise in popularity of recreationally used gabapentin is also occurring in the United States. Smith and colleagues  describe a near 3000% increase in the use of gabapentin to get ‘high’ from 2008 to 2014 among a cohort of 503 prescription drug users in the Central Appalachian region of the United States.
Motivations for misused gabapentin can be classified largely into three basic categories: recreational (e.g. get high or substitute for more expensive drugs), self-harm and self-medication (e.g. for pain or withdrawal symptoms from other substances). The majority of case reports involved individuals who had prescriptions for gabapentin, but took higher dosages than they were prescribed. Descriptive reports on gabapentin reveal an array of subjective experiences evocative of opioids (e.g. euphoria, talkativeness, increased energy, sedation), benzodiazepines (e.g. sedation) and psychedelics (e.g. dissociation). These effects do not appear to be specific to a particular dose, and may occur well within the therapeutic range. No pattern was observed in terms of dose taken or interactions between dose and motive or dose and effects achieved, which may be explained partially by the unpredictable pharmacokinetics and non-linear bioavailability of gabapentin . To date, no carefully controlled human laboratory studies have been published that sought to examine and characterize the abuse potential profile of gabapentin in comparison to other prototypical drugs of abuse. Overall, further empirical research is obviously needed to evaluate and characterize gabapentin psychopharmacology and the risks associated with gabapentin use more clearly, especially among those using it recreationally.
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Gabapentin is relatively inexpensive and, in fact, many individuals can acquire it free of charge or at a drastically reduced price under subsidy plans [63-65]. Further, due to its widespread off-label prescribing world-wide [8, 11, 12], it is relatively easy to receive gabapentin by prescription, as illustrated by physicians and the health-care system being the primary source of misused gabapentin in the United States and United Kingdom. These factors have enabled the market to be flooded with gabapentin and it has been referred to among the drug-using population as ‘a cheap man’s high’ (personal communication). It is important that prescribers recognize the current diversion of gabapentin and dispense judiciously.