Take any degree program you want in undergraduate university, but make sure along the way you complete "pre-med" requisites.
Competition to get into Medical School is fierce. Most people don't make it. Your undergraduate degree should be something marketable — such as Engineering. Chemical Engineering traditionally slots pre-med (and pre-pharmacy) courses most easily into the curriculum.
Osteopathy school are slightly easier to got into than Medical schools. You can become a psychiatrist from Osteopathy School.
After Medical/Osteopathy school, you would again be in competition for a Psychiatry Residence.