Objectives:
The answer to the question to what extent depressive symptoms which occur in the middle and late adolescence period affect the quality of life in adulthood.

Methods:
The sample group consisted of 308 adults out of 3,445 who had participated in a 2000 study of prevalence of depressive symptoms among students. 17 years later, letters were sent to all study participants with information about the purpose of the study and an original questionnaire, with quality of life and quality of social network scales (the Collaborative Research on Ageing in Europe Social Network Index – COURAGE-SNI and WHOQOL-AGE) attached.

Results:
The presence of depressive symptoms in the untreated population of adolescents is associated, in the case of women, with poorer education and fewer opportunities to work in adulthood compared to their non-depressive peers. In contrast, the men who were not depressive in adolescence take jobs in which they are more likely to earn a high income. An analysis of the quality of life showed statistically significant differences between men and women. In the group of non-depressive men, greater satisfaction with owned financial resources was observed. In the case of adult women, those who had been depressive in adolescence declared a sense of lower overall quality of life and satisfaction with the way of spending free time, satisfaction with achievement of life goals and owned financial means. Non-depressive women presented higher quality of social networks 17 years later.

Conclusions:
Long-term observation in our prospective study supports the hypothesis of a developmental character of adolescent depression.