What does “I never could take alcohol. I always said I was allergic to alcohol, and that’s actually a definition to alcoholism — an allergy of the body and an obsession of the mind,” mean?

See a translation

The star’s substance abuse problem was well-known, starting at only age 13 when she first started smoking marijuana, Fisher previously told The Telegraph. She said she later dabbled in drugs like cocaine and LSD. Fisher’s addiction was largely profiled in her 1987 best-selling, semi-autobiographical novel, Postcards from the Edge, which was later turned into a movie starring Meryl Streep.

“I never could take alcohol. I always said I was allergic to alcohol, and that’s actually a definition to alcoholism — an allergy of the body and an obsession of the mind,” Fisher told the Herald-Tribune in 2013. “So I didn’t do other kinds of drugs until I was about 20. Then, by the time I was 21 it was LSD. I didn’t love cocaine, but I wanted to feel any way other than the way I did, so I’d do anything.”