The aim of this study was to determine the distinctiveness of depression in the three phases of adolescence, the frequency of depression according to the age of the adolescents and the distribution of depression by gender. Also our goal was to show the comorbid conditions that are most common in adolescence, analyze their appearance according to the three phases of adolescence. The study included adolescents that were diagnosed with depression and frequented the infirmary for child and adolescent psychiatry. The data was collected from the medical documentation of the Polyclinic for rehabilitation of persons with developmental difficulties in Split. The data was entered and analyzed analytically using Microsoft Office Excel 2010. We analyzed 105 patients with depression. Regarding the distribution by gender, depression was more often found with female adolescents (52%). In early adolescence depression was more often found with boys. In median and late adolescence, depression was more often found with female adolescents. We found that the biggest frequency of depression was with adolescents aged 17. Specifically, behavioral disorders, tics and selective mutism were the most frequent of disorders in early adolescence. Behavioral disorders, psychotic depression, school phobia and stutter were the dominant disorders in median adolescence. In late adolescence we most often found behavioral disorders followed by school phobia and psychotic depression. Regarding comorbidity, 34% of the complete comorbidity was made up of addictive behavior. The second most often disorder was the depression connected with organic diseases which made up 24% of the comorbidity. 17% of the comorbidity was made out of obsessive compulsive disorder. In early adolescence, depression connected with organic diseases was most common, in the median adolescence obsessive compulsive disorder was most common and in the late adolescence addictive behavior was most common. Addictive behavior in early and median adolescence was more often found with boys and it manifested itself as computer game addiction. In late adolescence it manifested itself as substance addiction and it was more often found with female adolescents. The frequency of isolated depression was 27% compared to the depression connected with comorbidity which made up 73% of the total ddepression. Depression changes its form from early to late adolescence. It’s somewhat more frequent with female adolescents and in most cases is followed by behavioral disorders. Addictive behavior often follows depression and we must not neglect the potential differences in the addictive behavior.