Let's get something straight...
I am a fruitcake, a nutcase, a loon, a fruitloop, a nutjob, a mentalist, a whatever other slang name for someone who's a bit off their rocker you can come up with.
A few weeks ago I was in the nuthouse, the funny farm, the loony bin or whatever else you want to call a psychiatric hospital.
During my time in the hospital (7 weeks if you're interested) and over the many years where I have had to deal with mental health issues I have met hundreds of people who are also affected. Now listen very carefully.... not one of these people are offended by any of the words and phrases above. In fact the vast majority of them use them on a daily basis to describe themselves and during my hospital stay myself and other patients laughed the most when we were talking to each other about the ridiculous things that entered our minds and how big of a loon we were.
When someone in the hospital got a bit precious about something they would be treated with empathy and it explained to them to lighten up. In no uncertain terms one day my psychologist told me "no one is thinking these things except you Gareth", imagine your worst school mistress from the 1920s and that's the tone she used. There's a time and place for treating people with kid gloves and even then you are never dishonest for the sake of someone's feelings. That does more harm than good.
I've written before about the difference between sympathy and empathy and that is again what is needed here.
In short if someone claims that you cannot joke about mental health issues the chances are that person has never actually suffered from a mental health issue and is only out to try and make themselves look good. Of course they're actually using people who do suffer to do this, which is really lovely isn't it.
If someone is actually suffering from a mental health issue and has somehow fallen under the spell of one of these charlatans and is complaining about jokes and how it's making them suffer more please put them on to me because it isn't and they are in real danger from these control freaks.
So there you have it, joke away. Or don't, after all what do I know, I'm a raving loon.