What is the basic difference between a psychologist and psychiatrist?

Different types of: Training. Psychiatrists study medicine and then specialize in psychiatry and medication 4 psychiatric disorders. Psychologists specialize in psychology, therapy, psyche testing and mental health from BA to MA to doctorate and don't prescribe medication.

Therapy vs meds: Speaking very generally, most psychologists hold either a PhD or a PsyD degree (I hold both) and practice psychotherapy. Psychiatrists hold either an MD or a DO degree, and they prescribe psychotropic medications, and generally do not do all that much therapy these days, but years ago psychiatrists would do both.