This book presents and diagnoses one of the most serious personality disorders: Borderline Personality Disorder (BPD). It examines this disorder from a psychoanalytic perspective, drawing on clinical and practical experience. The impact and repercussions of this disorder on adolescent girls and boys are extremely serious, affecting the individual, the family, and society. This is especially true given the disorder's increasing prevalence in recent years and the significant financial burden it places on many families. Therefore, this study aims to uncover the key dynamics contributing to BPD in adolescents, understand their psychological makeup, and identify the most common symptoms, traits, and signs. The study also explores the contributing factors to BPD in adolescents aged 16-18 years (average age 17). The sample consisted of five participants: four girls and one boy. The following tools were used: in-depth clinical interviews, the Eysenck Personality Questionnaire (EPQ), the Tennessee Self-Concept Test, the Self-Esteem Test, the HTP, and the Animated Family Drawing Test. The KFD, TAT, Rorschach test, as well as free or spontaneous drawings and autobiographies of the examinees, are used using the clinical method. This then assists specialists such as psychiatrists and psychotherapists in developing specialized, effective, and precise preventive, guidance, and therapeutic programs.