The former Scottish Labour Party politician, who resigned in disgrace in March 2010, also plans to speak in public for the first time about his personal crisis.
Mr Purcell, who had represented the Drumchapel and Anniesland ward in Glasgow before his resignation, said he was looking forward to addressing a small conference of dentists at the Clyde Dental Centre in Glasgow on September 19.
The 41-year-old said: "I will be talking about what I have learned from the issues involved. Since it happened, I have studied a lot about depression and stress."
Mr Purcell, who helped bring the Commonwealth Games to Glasgow, added: "I'm a lot stronger now. Time is a great healer."
Purcell was a Labour high-flyer tipped as a future First Minister when his career dramatically collapsed amid claims of cocaine use and blackmail plots. He had married but later split from his wife, announcing he was gay.
Anti-corruption officers mounted an investigation into his time at the City Chambers but, last year, the Crown Office said there was insufficient evidence of criminality.
In the same month, an incident at his flat in the Merchant City resulted in a man being convicted of assault.
In court evidence, Mr Purcell was described as "very drunk" with blood on his shirt.
Mr Purcell said there was "no chance" of a return to public life.
"I've been working for quite a while now," he said. "I have been doing consultancy work, in change management."
The invitation to speak at the dentists' gathering came from a friend who runs the practice where it is being held.
The £45-a-head evening function is being hosted by Dr Robert Broadfoot and will address the issues of "stress, anxiety and professional burnout".
Advance publicity states: "At the meeting, [Steven] will discuss the factors that led to his breakdown and the steps that he took to help rebuild his life. Many dentists will be able to relate to these work-related pressures and Steven will give an insight to stress, anxiety and its management from a non-dental perspective."