Whilst I think a catalyst can help, I believe it's completely up to the individual to recognise if there is change needed. Then work to change it, if outside help is needed that's terrific but the change must come from the core of the individual.

I do think people can change, but I know of alot of people that although want to change are still stuck in the negative behaviours and can't tear themselves away.

It's too individual to cast any sort of blanket statement. Some people can give up smoking easily, some can't. Some have massive catalysts in the lives and all the help in the world but can't/won't change and others you think will NEVER change manage to do so all on their own.