Grace Smith says she was able to give up alcohol, but that quitting smoking seemed impossible.
"I was living in the Lower East Side, and that's what all my friends did too - we worked really hard all day long, and we partied really hard all night. It took a real toll on me, physically and mentally."
The 34-year-old is also a regular on US television, and the author of two hypnosis books.
Born and raised in New Jersey, Grace gained a combined degree in English, business management and religious studies from Wagner College in New York. She then enrolled on a masters in human rights studies at Columbia University.
In recent years interest in Grace and her now Florida-based business has grown strongly, thanks in no small part to her presence on US TV. She has appeared on CBS's daytime health chat show The Doctors, and Sony's The Dr Oz Show.
To help train and certify more hypnotherapists, in 2016 Grace opened her own school, which is approved by both the International Association of Counselors and Therapists, and the International Hypnosis Federation.