Which nursing course should I do adult or mental health?

go for the one that you have the best vibes about. You've already answered your own question - adult nursing. Ok so there are more mental health jobs - that's because people don't want the jobs, hence more vacancies (and why would that be?). Also how can you be sure 3 years from now that that will still be the case?

it depends where you live! but if your in australia when you doing your nursing training you will cover mental health and do a prac on mental health ward, if outside australia check the nursing course to see if you do a unit in mental health and whether there is a prac on the ward or do a mental health nursing degree, where you can work with adults and mental health clients, your other options are doing a counselling or psychology course instead which gives you qualifications in mental health fields also mental health workers do work with adults as well! do talk to a career advisor and research all courses available !!!!!! good luck

Seems you should be able to find time to try both and see which is best for you. Try volunteering and getting some personal insight,

mental health