Significant advances have been made over the past two decades, associated with an increase in methodologically advanced research, into the treatment of post-traumatic stress disorder (PTSD). However, interest in the topic of PTSD has not only not waned, but seems to be gaining strength. The main reason for this is the difficulty in clearly defining the phenomenon, which is related to the constant updating of the criteria for post-traumatic stress disorder in medical classifications. The search for general standards and methods of measuring this disorder in relation to the age of the patient is another area of dispute among specialists. The conceptualization of the patient’s problem, on the other hand, is based on knowledge of psychopathology, which describes the mechanisms of formation and maintenance of disorders. The accuracy of the conceptualization is linked to appropriate psychotherapeutic interventions that result in the patient’s improvement or recovery. Cognitive models of PTSD largely explain the functioning of people after traumatic life events. This paper presents the classic transaction model of stress and coping by Richard S. Lazarus and Susan Folkman, Anke Ehlers and David Clark’s cognitive model of persistent PTSD, and the cognitive model of processing trauma according to Brewin et al. In addition, cognitive-behavioral psychotherapy methods with empirically proven efficacy in the treatment of PTSD in children, adolescents and adults are reviewed. However, psychotherapy models and programs for children and adolescents with PTSD are mostly a modified version of an adult PTSD treatment and require further clinical development. In addition, due to the introduction by WHO of a new nosological entity in the form of complex PTSD, new theoretical models, diagnostics tools, and validated methods are needed to help treat this disorder