I think mental health questions should be on-topic.
Certainly the description (Q&A site for physicians, doctors, medical specialists, dietitians and anyone with health-related questions
) would seem to include them. And I can't think of any good reasons to bar people with mental health questions from this site.
It would also help make the site stronger by increasing the size of the community.
Another point is that questions could be related to both "physical" and mental health. For example,
- @foregon's question:
What are the health benefits of spending time at the beach (on the sand, in the ocean, in the sun)?
- @Wossname's question:
Do different macronutrients (protein, carbohydrate, fat) have different effects on hunger?
I believe that there haven't been many mental health questions since there was a separate proposal for that when this proposal started.