The aim of this study was to increase knowledge about young adults` most common mental health diseases, what their rehabilitation is like and how the nursing personnel has felt to execute it. The purpose of this study was to find out the nursing personnel`s experiences of treating young adult mental health clients at their rehabilitation phase.

Theory of the thesis was collected from literature of this subject and previous researches. Theory is focused on young adults` most common mental health diseases, mental health rehabilitation treatment methods and nursing personnel`s resources to support young adults. The thesis approach was qualitative and the research material was gathered by using a questionare. The material was analysed by using an inductive content analysis. The inductive content analysis`s purpose is to clear the material and in that way produce new information about researching fact.

Main results were that nurses have experienced executing the rehabilitation phase nursing challenging, due to young adults` psychoactive drug using. Nursing personnel feels they can meet the young adults` needs for the most part. Family, friends and peer support are very meaningful in the order of the rehabilitation to work. Nurses brought to attention that increasing mental health working resources, preventing mental health problems, developing the existing therapyforms and lowering the chance of getting in to mental health treatment are the biggest developing needs of mental health work.