Post-traumatic stress disorder (PTSD) is an anxiety disorder that can develop after experiencing a terrifying event or ordeal in which grave physical harm occurred or was threatened. People with PTSD have persistent frightening thoughts and memories about the traumatic event and may experience sleep problems, feel detached or numb, or be easily startled. Studies have shown that PTSD occurs at high rates among people with serious mental illnesses (SMI), such as bipolar disorder, schizophrenia, and major depression. Research has also proven that cognitive behavioral therapy (CBT) is an effective PTSD treatment for caucasians living in rural areas when it is administered by a PhD-level clinician. It is not clear, however, how successful this treatment will be when it is delivered to a minority population by frontline mental health clinicians in an urban setting. This study will evaluate the effectiveness of tailored CBT in treating PTSD in people with additional mental illnesses who live in urban areas of New Jersey.