Ideation-to-action framework of suicide: a systematic review of the Integrated Motivational-Volitional model and the Three-Step Theory

The new generation of suicide models diverges from previous theories by embracing the ideation-to-action framework. Among these, the Integrated Motivational-Volitional (IMV) model and the Three Step Theory (3ST) elucidate the circumstances under which suicidal ideation arises and the subsequent transition from thoughts to behaviour. This systematic review aimed to compare the two models and assess the validity of each of their phases. Four electronic databases were searched for studies published after 2011 for the IMV model and after 2015 for the 3ST, yielding a total of 65 eligible articles. Among these, 51 focused on the IMV model, 12 on the 3ST, and two examined both models. Overall, while the IMV model was significantly more extensively studied than the 3ST, both models received partial support, which varied according to their respective phases or steps. The formation of suicidal ideation was robustly supported; however, the transition to action yielded conflicting findings, primarily due to operational and ethical challenges inherent in suicidology. Regarding the IMV model, our review underscores the necessity for further research that tests all three phases of the IMV together and addresses understudied variables, particularly the threat-to-self, motivational, and volitional moderators. The main limitations identified within the 3ST literature were largely related to the inconsistent operationalization of key variables and the use of inappropriate measurement instruments, which impeded a comprehensive assessment of the implicated factors, especially concerning pain and connectedness facets.