I am wondering if i could have a bit of advice. I was wondering if autism had an effect on mental health issues and vise versa and if so how do people cope with this?
When you consider having to deal with school, socialising, work, etc. undiagnosed, depression is not surprising. A diagnosis does not mean the end of depression but it is a step forward.
My diagnosis has meant that I can at last begin to do what is natural to me without having an internal argument about whether it is "right" then trying (and failing) to behave in a neurotypical way.
I agree with Trainspotter that modern society does autistic people no favours. Indeed, I would go further and modern society harms autistic people; I cannot make up my mind whether such harm is deliberate.
You may wish to read this article about mood disorders for people with autism:https://www.verywell.com/mood-disorders-and-asperger-syndrome-259943
Autism Speaks' report Autism and Health contains a section on autism and mental health. The report may be downloaded via:www.autismspeaks.org/.../autism-and-health-special-report-autism-speaks