To earn your Ph.D. in psychology, you will need 5-7 years to earn the degree. You will need to finish all of the required classes and you also will have to do an internship or residency of some sort. A Ph.D.program usually ends with a detailed and long dissertation.This paper tends to be 200-300 pages in length and can take you a year or more to complete. The lengthy dissertation is a major reason why earning your Ph.D. takes so long. To earn your Psy.D. degree, you need 4-6 years to finish the degree.ou will need to finish all of the required classes and you also will have to do an internship or residency of some sort. A Ph.D. program usually ends with a detailed and long dissertation. This paper tends to be 200-300 pages in length and can take you a year or more to complete.