I want to make a further comment in addition to the one above as regards heat and anti depressants and some other MH drugs.
As they do make one more vulnerable but the link isnt clear on the information available on the list you get with your meds.
If you look at both the list of common side effects (one in ten) and less common ones (one in a hundred) it is not alluded to. those are worth looking up but effects are very individual.
So I looked for a direct link and found that it appears to be that all these meds - as I'm sure all of us on them know - do give you a dry mouth and in fact can interfere with digestion and the TMI stuff.
But it's the far more rapid dehydration is where the link is. We are dehydrating faster than people of our age more rapidly, and therefore also symptoms like dizziness and dryer skin etc.
The answer is drink, drink, drink water. Cover up dont expose already dry skin etc.
Which we don't always want to do if not near a toilet at the right time!
As for staying on them for years unchecked it's a very bad idea. Many many MH meds are prescribed in slightly lower doses to what they not so tactfully call "the elderly".
There are also developments in terms of better more targeted drugs, new knowledge on old or new drugs, but we are entering the territory of how much specialist knowledge GP's have as compared with a psychiatrist and of course that varies.
A good example of this is Amitriptyline, once the go to drug for depression, and it worked very well for me for some time. But it was not favoured for good reasons (toxicity if overdose) and was used less but is now found with very low doses it helps a lot with chronic pain relief.