Recognizing the Unknown: A Case of Complex Posttraumatic Stress Disorder and Role of Trauma-focused Cognitive Behavioral Therapy

Abstract Complex posttraumatic stress disorder (C-PTSD) is a distinct diagnosis recognized in the International Classification of Diseases-11, characterized by core PTSD symptoms alongside disturbances in self-organization, including emotional dysregulation, negative self-concept, and interpersonal difficulties. Due to symptom overlap, C-PTSD is often misdiagnosed as emotionally unstable personality disorder (EUPD), potentially resulting in suboptimal treatment. We report the case of a 21-year-old female graduate student with a history of multiple childhood traumas. She remained high-functioning until the sudden death of her mother triggered severe psychiatric symptoms – anger outbursts, self-harm, panic-like anxiety, and sleep disturbances. Initially misdiagnosed with EUPD and treated with mood stabilizers and antidepressants without significant improvement, she was later accurately diagnosed with C-PTSD. Following this, she received trauma-focused cognitive behavioral therapy (TF-CBT). After 2 weeks of inpatient care, her PTSD Checklist for DSM-5 score reduced from 58 to 43. This case highlights the importance of diagnostic precision in guiding effective, individualized treatment. Trauma-informed approaches, combined with TF-CBT, yielded marked clinical improvement, highlighting the necessity of addressing the root psychological trauma rather than solely targeting symptomatic relief.