Gable Tostee may have Asperger's syndrome, according to a psychiatric report revealed on Friday by Brisbane's Courier-Mail.
Mr Tostee was acquitted of the murder of New Zealander Warriena Wright on Thursday. He had locked Ms Wright outside after a drunken fight - and she climbed over the railings and fell to her death. Afterwards, he walked around the city, and ordered pizza.
This wasn't the first time Mr Tostee had faced court.
In 2006, Mr Tostee was sentenced for his role making fake ID cards for teenagers so they could get into pubs. When police shut down the racket in late 2004, it's estimated he and his partner-in-crime had made AU$30,000.
In a psychiatric report presented to the court at the time, Dr Ian Curtis said Mr Tostee was a "partially disabled person" - who had a limited ability to connect with other people emotionally.
Mr Tostee was described as most likely suffering from Asperger's syndrome.
"Tostee presented as a socially distant, emotionally estranged person with whom it was impossible to establish a clear-cut rapport," the court was told.
"Dr Curtis noted that Tostee had no regular social life and was not equipped to deal in a discriminating manner with people whom he met socially."
Dr Curtis also said Mr Tostee suffered from Obsessive Compulsive Disorder.
He had "a tendency to be severely introverted and fantasy ridden so as to be relatively divorced from the knowledge of the consensus of realities that govern the lives of normal people."
The court was told Mr Tostee would need continued help.
A medical report by Dr Derek Matthew had similar findings.
"Dr Matthew concedes that he is frequently not sure what plane Tostee is thinking on and that there is an abstract quality at times in his communication," the court was told.
"(He) states that from an early age it has been observed that Tostee has above average intellect but at the same time is handicapped by behavioural problems that come partly under the umbrella of Asperger's syndrome with very marked obsessional compulsive and anxiety features."
After his court acquittal, Mr Tostee showed no emotion and refused to speak to media. Instead, he walked away, with an expressionless face.