FOR many years, Nicholas William Ryan's real mother kept drumming into her son's head "when you were born, you were a mistake".
A Rockhampton court yesterday heard how Ryan, 32, grew up believing his grandmother was his mother.
When his grandmother, who was described as Ryan's "bodyguard", died more than 20 years ago, the defendant started dabbling in alcohol, cannabis, methamphetamine and eventually heroin.
It was after her death, he discovered the woman he had called his sister was in fact his mother.
She was 12 years old when she gave birth to Ryan.
The Rockhampton District Court was the place Ryan was reminded of his tumultuous childhood after he yesterday pleaded guilty to one count of assault causing bodily harm after a drunken night out.
The court heard on February 1, 2013, Ryan and a woman were drinking at The Berserker Tavern.
About 2am, the pair made their way to the tavern beer garden and started chatting to a man from Western Australia.
Sometime after entering the garden, Ryan, the woman and the man left the tavern.
The woman was walking ahead of Ryan and their new acquaintance, when Ryan punched the man for reasons not heard in the court.
The man fell to the ground and was suspected to have hit his head on a nearby stone or rock, the court heard.
A witness called an ambulance and he was rushed to Rockhampton Hospital, where he underwent an emergency operation to have a head laceration stitched up.
He ended up with 90 stitches and staples.
Ryan's defence lawyer, Maree Willey, said her client had a horrific upbringing, marred by family members who often blamed him for doing things other relatives had done.
She said a cousin of Ryan's mother also constantly abused him.
Ryan had already served 143 days in pre-sentence custody for the incident.
Judge Paul Smith sentenced him to three years imprisonment, releasing him on parole immediately.