Post-traumatic stress disorder (PTSD) was included in the DSM-III (1980), mainly due to the relatively large numbers of American combat veterans of the Vietnam War who were seeking treatment for the lingering effects of combat stress. In the 1980s, various researchers and clinicians suggested that PTSD might also accurately describe the sequelae of such traumas as child sexual abuse and domestic abuse. However, it was soon suggested that PTSD failed to account for the cluster of symptoms that were often observed in cases of prolonged abuse, particularly that which was perpetrated against children by caregivers during multiple childhood and adolescent developmental stages. Such patients were often extremely difficult to treat with established methods.