Treatment Resistant Depression (TRD) is a type of depression that does not respond to traditional treatments such as antidepressant medications, psychotherapy, or other forms of therapy. People with TRD may experience symptoms such as persistent sadness, loss of interest in activities, difficulty concentrating, fatigue, and changes in appetite and sleep. Treatment options for TRD may include medications, electroconvulsive therapy, transcranial magnetic stimulation, and other forms of therapy.