Most studies on drug use are conducted in adolescents and young adults, who are at life stages associated with the greater use of drugs. We presented data from an older cohort, which has presumably passed the experimentation age. While this contributes to the scarce literature on drug use in later parts of the lifespan, the advantages of a lifespan perspective come at the cost of having fewer current users in this older cohort. In addition, older cohorts only include the survivors among those who started drug use early in life, which may introduce attrition and other biases. A review of the literature [20] suggested that studies that involve older populations (over the age of 30 years) report weaker association of Conscientiousness-related traits and drug use.
