The development of loneliness from mid- to late adolescence: trajectory classes, personality traits, and psychosocial functioning.

Although loneliness is a common problem across late adolescence, its developmental course has not been investigated in depth in this period of life. The present study aims to fill this gap by means of a five-wave cohort-sequential longitudinal study spanning ages 15 to 20 (N = 389). Both variable-centered (i.e., latent growth curve modeling) and person-centered (i.e., latent class growth analysis) approaches were used. Variable-centered analyses showed that loneliness generally decreased over time. Person-centered analyses pointed to considerable inter-individual differences in the development of loneliness, and identified five trajectory classes (i.e., stable low, low increasing, moderate decreasing, high increasing, and chronically high). These five trajectory classes were differentially related to personality traits at age 15 (i.e., extraversion, agreeableness, and emotional stability) and psychosocial functioning at age 20 (i.e., depressive symptoms, self-esteem, anxiety, and perceived stress). These findings underscore the additional value of studying subgroups regarding the development of loneliness.