Sounds like you looked at this prior. Many people with substance use/abuse disorders also have underlying personality disorders. The substance use is often an easy self medicate solution. In your spare time give this a read.
https://www.mentalhelp.net/articles/the-...-disorder/
https://www.mentalhelp.net/articles/the-...-disorder/
Being told you're delusional does not necessarily mean you're mental.