Non-suicidal self-injuries (NSSI) and suicidal conduct (SC), including completed suicide, are major public health problems among adolescents and young adults. They are seen ubiquitously in both clinical and community populations. Although these two behaviors frequently co-exist, distinguishing them clearly remains complex. Indeed, the differences between NSSI and CS have been investigated more than their underlying relationships, as have the factors contributing to the transition between NSSI and CS. This narrative literature review aims to report on the current state of knowledge regarding the articulations between NSSI and CS, in light of Hamza et al.’s integrated model that proposes hypotheses of links between these behaviors. In addition to this article, our review is based on later articles or articles not cited by Hamza et al., describing cross-sectional, longitudinal, and meta-analyses targeting the links and/or differences between CADSIS and CS in adolescents and young adults aged 12 to 25 years. Based on the various findings, Hamza et al.’s model seems interesting because it incorporates common risk factors and a form of habituation to explain the frequent progression from CADSIS to CS. However, if this trajectory is frequent, it is not the rule. It would therefore be necessary to test all the links and variables that potentially mediate the CADSIS-CS relationship according to their model.