Several factors may predispose individuals to developing CUD. Additionally, these same individuals may have an equal predisposition to developing a comorbid mental illness [119, 150]. The addiction vulnerability hypothesis outlines pre-existing vulnerabilities that one may have to developing an addiction. There are factors, including impulsivity, genetic predisposition, epigenetic states, and overlapping neurobiology that bias an individual to not only mental illness, but also to developing SUDs, including CUD [21, 115, 139, 146]. For example, genetic studies have confirmed vulnerability models in which there are shared genetic predispositions to CUD and, for example, major depression [20, 74, 134]. It is known that CUD and mental illness are highly prevalent together. For example, one study has described how those who are addicted to cannabis, compared to non-addicted users, report mental health problems, including anxiety and depression, further emphasizing the potential comorbid vulnerability model [143]. Not only are there shared vulnerabilities, but the presence of a mental illness itself is a vulnerability factor for addiction, despite the heterogeneity across comorbidities [24, 82, 131, 138]. For example, depression and anxiety have been described as
