AbstractPurposeTo explore associations between preterm birth and use of medications in young adulthood as a proxy for different diseases.MethodsWe linked data on birth characteristics from the Medical Birth Registry of Norway (1967–1999) and the Norwegian Prescription Database (2004–2015). Individuals born as singletons during 1974–1984 and alive at the age of 31 were included (main analyses) (n = 450 555). Relative risks (RRs) with 95% confidence intervals (CIs) of using different medications were estimated by log‐binomial regression. Population attributable risk and attributable risk percentage (PAR% and AR%) due to preterm birth were calculated.ResultsIndividuals born preterm used more specific medications at age 30 than those born at term. The risks of being dispensed psychotropic medications overall and the subgroups antiepileptics, antipsychotics, anxiolytics and hypnotics were elevated in individuals born preterm. For attention‐deficit/hyperactivity disorder medications, the risk was elevated in males born extremely preterm (RR 5.8; 95%CI: 2.2–15). The risk of being dispensed antiasthmatics increased by shorter gestational ages. For psychotropic medications, PAR% was 0.6% in males and 0.7% in females at age 30; AR% was 13% in males and 17% in females. For antiasthmatics, the corresponding figures were 1.4, 1.1, 24 and 23%.ConclusionIndividuals born preterm used more psychotropic medications overall and antiasthmatics around age 30 than those born at term. The proportions using these medications increased for those born at earlier gestational ages. Those born preterm, especially before 32 weeks of gestation, should be given special attention during early adulthood regarding development of symptoms and signs of certain diseases. Copyright © 2017 John Wiley & Sons, Ltd.