Internet-Based Cognitive Behavioral Therapy With Treatment as Usual for Generalized Anxiety Disorder and Major Depressive Disorder in Taiwan (ICBT-TW)

Inclusion Criteria: * Age between 20 and 65 years. * Diagnosis of Generalized Anxiety Disorder (GAD) confirmed by a psychiatrist. * Diagnosis of Major Depressive Disorder (MDD) confirmed by a psychiatrist, without acute suicidal risk (screened by PHQ-9 Item 9; score of 3 requires further clinical assessment to exclude active suicidal plan or recent self-harm). Exclusion Criteria: * For GAD ICBT participants * Current or past history of obsessive-compulsive disorder, panic disorder, bipolar disorder, eating disorder, schizophrenia, or substance abuse. * Severe depressive symptoms impairing daily functioning. * Current suicidal ideation. * Experiencing acute life stressors (e.g., domestic violence, ongoing treatment for serious physical illness). * Currently receiving psychological counseling or psychotherapy. * Other serious factors limiting participation (e.g., intellectual disability, significant cognitive impairment, severe vision or hearing impairment). * For MDD ICBT participants * Diagnosis of bipolar disorder, eating disorder, schizophrenia, psychotic symptoms, or substance abuse. * Current suicidal ideation or recent self-harm (PHQ-9 Item 9 score of 3 triggers further assessment; exclusion if active suicidal plan or recent self-harm present). * Experiencing acute life stressors (e.g., domestic violence, ongoing treatment for serious physical illness). * Currently receiving psychological counseling or psychotherapy. * Other serious factors lim…