That is a problem with a lot of disabilities, not just mental health.
Someone may look fine when they are out in public for an hour but may be non functioning the other 23 hours in a day.
I agree with jammer. I look fine except to a trained therapist. After speaking for a few minutes a trained therapist can see I am very ill.
Proving invisible illness or disability is one of the greatest challenges in a society where many people have unconscious bias against anyone claiming disability benefits.
And conscious bias in many cases!!
It’s interesting the assumptions people make.
I use a walker and some people automatically assume that I am mentally challenged.