Physical abuse is an act of a person involving contact of another person intended to cause feelings of physical pain, injury, or other physical suffering or bodily harm. In most cases, children are the victims of physical abuse, but adults can also be victims, such as in a domestic context. Alternative terms sometimes used include physical assault or physical violence, and may also include sexual abuse. Physical abuse may involve more than one abuser and more than one victim. Physically abused children are at risk for later interpersonal problems involving aggressive behavior, and adolescents are at a much greater risk for substance abuse. In addition, symptoms of depression, emotional distress, and suicidal ideation are also common features of people who have been physically abused. Studies have also shown that children with a history of physical abuse may meet DSM-IV-TR criteria for posttraumatic stress disorder (PTSD). Physical abuse has been described among animals too, for example among the Adélie penguins.