To compare the motives of non-suicidal self-injurious behavior (NSSI) in terms of nosological affiliation, gender and age group.Ninety-one patients, 80 women and 11 men, aged 13-24 years old, who independently applied to the SPbSPMU consulting center, were selected. The patients were examined clinically as well as using the Russian-language adapted version of the Inventory of Statements about Self-injury. The younger subgroup consisted of 54 people under the age of 18, another group of age above 18 numbered 37 participants. At the preliminary stage, patients with schizophrenia, organic mental disorders, etc were excluded. Based on the clinical and psychopathological assessment, 3 clinical groups were identified. The first group (n=50) consisted of patients under 18 years old with different subtypes of pubertal behavioral disorders (ICD-10 F91) and patients with emotionally unstable personality disorder (F60.3). The second group is represented by patients with mild or moderate depressive episodes (F32). The third group included patients with various eating disorders.The selected groups did not differ by the age of patients, the age of onset of self-injurious behavior and its duration. There were also no differences in the leading types of NSSI depending on gender, age subgroup, or clinical diagnosis, which confirms the currently prevailing view on NSSI as a transnosological phenomenon. The motives of NSSI also did not differ depending on the nosological form. Gender and age differences in the motives of NSSI were revealed. In male patients, the motive of «sensations seeking» (p=0.037) and «peer-bonding» (p=0.036) significantly prevailed. In the younger age subgroup, the motives of «self-punishment» (p=0.032) and «peer-bonding» (p=0.026) prevail.The nosological non-specificity of NSSI, which is manifested in the similarity of the age of onset, duration, types of NSSI and motives for committing them in different disorders, allows us to consider this phenomenon as a separate dimensional characteristic of a mental illness, more dependent on internal patterns, gender and age characteristics than on its nosological affiliation.