Yes. According to the most recent edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), alcoholism, or alcohol use disorder (AUD), is a diagnosable mental illness.
The DSM is a book full of things that (a particular group of) academic doctors think should be considered to be illnesses. It's previously included homosexuality and "gender identity disorder" (transgenderism).
It's a not a bad source, obviously, but being in a book does not make things diseases or not.
That said, in my (medical) opinion, alcoholism and other addictions are much better to be considered (and treated) as diseases.
You minimise it as "being in a book". The book is: "a publication by the American Psychiatric Association for the classification of mental disorders". Are you part of the psychiatric field?
well thanks, you probably didn't see that what I posted was in response to the question "Are there people telling you that you’re incorrect or even mentally ill because you identify as a recovering alcoholic?"
Yes. According to the most recent edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), alcoholism, or alcohol use disorder (AUD), is a diagnosable mental illness.