Effectiveness of Behavioral Activation Treatment for Schizophrenia

Inclusion Criteria: * Patients who have received a primary diagnosis of schizophrenia * Patients who are at least 18 years old and under 65 years old * Patients who show a score of 3 or higher on at least two negative symptom items in the Positive and Negative Syndrome Scale (PANSS) * The subject selection period is until December 31, 2021, from the IRB approval date. Exclusion Criteria: * Patients with a history of organic brain syndrome, epilepsy, or traumatic brain injury * Patients with comorbidities such as intellectual disability, current alcohol or other substance dependence * Patients who show a score of 5 or higher on at least two positive symptom items in the Positive and Negative Syndrome Scale (PANSS) * Patients who have received a diagnosis of major depressive disorder according to the DSM-V criteria by a specialist in psychiatry * Patients who have received psychological services including components of behavioral activation therapy * Patients who are at risk of self-harm or harm to others.