Experts believe that adolescence is more challenging than childhood and is of critical importance. It is the period when the youth must be able to seek a philosophy for life and find an identity. Unfortunately nowadays most youths cannot learn developmental tasks successfully. The present descriptive study aims to identify pathological social-behavioral disorders and their impact on students' underachievement. The sample of the study consisted of 480 students aged between 12 and 17. Instrument of collecting data was a researcher-made likert-like questionnaire with 53 items, 15 positive and 38 negative. The face validity of the questionnaire was calculated with the Agreement coefficient formula. After calculating the consensus opinion of 20 experts, the questions whose coefficient of agreement was less than 70% were eliminated. Its reliability was also calculated as 85%, using Cronbach alpha coefficient. Results showed that the rate of disorders in both male and female students will be equal if the overall level of disorders is considered separately. However, when a certain kind of disorder is considered, some differences are visible in both groups. Disorders include incompatibility, irritability, risk acceptance, indecisiveness, irresponsibility, feeling guilty, lack of trust in others, disrespect for authorities. The impact of these disorders on underachievement is more significant in girls than that of boys.