Ms Henderson-Watt said such reactions could be prevented with counselling and proper guidance from responsible adults in the community.
Not all abused children needed on-going counselling, she said. Those that needed long-term counselling were the ones who didn't tell anyone about their abuse.
Ms Henderson-Watt said Miriam House received calls nearly every week from parents, caregivers and teachers complaining that abuse had taken place.
"We've had a big campaign about why it's not okay to have violence in our community and it attracted a huge response. Now we need a similar campaign about sexual abuse," she said.
"What's also needed is to teach our kids that it's not okay to abuse other kids because they often learn such behaviour from adults."
Ms Henderson-Watt said paedophiles would often set children up to not be believed, which would enable offending to continue until the victims mustered up enough courage to come forward.
Miriam House has provided support to some of the youngsters affected by convicted paedophile James Parker's offending.