The purpose of the current thesis was to elucidate the impact of the different social withdrawal subtypes (unsociability, avoidance, shyness, isolation) on several psychological outcomes - life satisfaction, loneliness and depression - in a Norwegian sample of young adults. Social withdrawal research has mainly focused on shyness and unsociability, and mainly with children. Therefore, there is a clear gap in the knowledge regarding the differences between each subtype, and the possible effect on young adults’ psychological adjustment. The four subtypes can be categorized in a preference for solitude and preference for socialization group. An additional goal was to validate a relatively new scale for measuring social preferences, the Social Preference Scale-Revised, in a Norwegian sample for the first time. The present study was questionnaire-based, containing measures of social preferences, satisfaction with life, loneliness and depression. The sample consisted of 240 Norwegian university students. An exploratory and a confirmatory factor analysis were conducted to validate the Social Preference Scale-Revised and differentiate between the subtypes of social withdrawal. Furthermore, multiple regression analysis was used to predict the effect of social withdrawal subtypes on life satisfaction, loneliness and depression. The results of the factor analyses corresponded to a good model fit. The multiple regression analyses revealed that all subscales of social withdrawal were significant predictors of loneliness. However, only shyness and avoidance were significant predictors of satisfaction with life. Unsociability, shyness and avoidance were additionally significant predictors of depression.