A Longitudinal Analysis of Patterns of Ketamine Use among Young Injection Drug Users

Background: Longitudinal studies of drug use can offer important insights into patterns of use, including cessation, continuation, and binging.

Methods: A sample of 69 young injection drug users (IDUs) were interviewed about ketamine use (sniffing and injecting) every three to four months over a two year period. IDUs qualified if they were between the ages of 16 and 28 years old and had injected ketamine at least once in the preceding two years.

Findings: Nearly half the sample (46.4%) reported no ketamine use during follow-up, and could be described as “experimentalists.” The remainder of the sample (53.6%) consisted of three primary groups: “sniffers only” (14.5%); “infrequent injectors” (30.4%) who injected between one and six times during follow-up; and “consistent injectors” (8.7%) who injected between nine and 41 times during follow-up. Compared to other groups, experimentalists more often had injected ketamine only once at baseline interview, initiated injection drug use with ketamine, preferred modes other than injection to administer drug of choice, and sold ketamine. In contrast, consistent injectors more often injected ketamine ten or more times at baseline interview, sniffed ketamine once or never at baseline interview, preferred injection as the primary mode to administer drug of choice, and had limited involvement in selling ketamine.

Conclusions: These findings suggest that prior drug using history – including preferred mode of administration - is an important predictor of future ketamine using patterns. Additional qualitative data will help formulate a descriptive and predictive model of patterns of ketamine use among young IDUs.