Just knowing that a person is being destroyed by, most likely, someone close can be a melting pot of emotions and feelings that would force someone to invest in a complex or adopt a neurosis. .
The National Center for Post Traumatic Stress Disorder has a detailed listing on it's website (www.ncptsd.org) for sexual abuse related symptoms:.
Some children may show symptoms of PTSD (post traumatic stress disorder), including agitated behavior, frightening dreams, and repetitive play in which aspects of the abuse are expressed. Because of their sexual abuse, children may show sexual behavior or seductiveness that is inappropriate for their age. As a result of abuse, children, especially boys, tend to "act out" with behavior problems, such as cruelty to others and running away. Other children "act in" by becoming depressed or by withdrawing from friends or family. Sometimes children may try to injure themselves or attempt suicide.
Reviewing these symptoms while applying them to Freud's Wolfman unfolds many realizations. Some children may show symptoms of PTSD (post traumatic stress disorder), including agitated behavior, frightening dreams, and repetitive play in which aspects of the abuse are expressed. In this sentence one can see the frightening dream of the primal scene can, alone, be a sign that the Wolfman may have been abused like his sister. Just seeing his parents in such an intimate setting is a form of abuse, but there could lay more elsewhere. Because of their sexual abuse, children may show sexual behavior or seductiveness that is inappropriate for their age. Here one can clearly see the sister's behavior as the norm of a victim of abuse. As a result of abuse, children, especially boys, tend to "act out" with behavior problems, such as cruelty to others and running away. It is not hard to see that the young Wolfman displays such behavior with his fantasies of beating a horse and his real-life actions of killing insects.