This is not really a discussion topic, but I recently ran across some vids on Youtube which show presentations for psychologists / therapists on dealing with clients who have kinks. Although they aren't aimed at us, and talk about kink/BDSM in a more general way than just ageplay or ABDL, I think they might be interesting for people with interest in psychology / mental health.
BDSM & Sexual Pleasure - Dominic Davies
The Kink Paradox - DK Green
Living and Working in the Kink Communities: Professional Boundaries and Ethics - Dominic Davies
The place of kink in psychotherapy and counselling training - Henry Strick van Linschoten