The amount, idea content, visual imagery and emotional tone of dreaming can be changed by trauma. The lives of patients with PTSD is much more influenced by dreams than “normal” people. PTSD patients have dreams with greater complexity, fright and anxiety, which they recall more vividly than other people, and to which they compulsively return each night, sometimes for months, years, even decades. Patients with TBI experience shortened, fragmented REM sleep and tend to have fewer dreams.