A Salford gunman who shot dead Indian student Anuj Bidve is not a psychopath but has all the characteristics of severe Anti-social Personality Disorder, Manchester Crown Court heard yesterday.
Defence psychologist Dr Sanya Krljes told the jury in Anuj Bidve’s murder trial how she had reached the diagnosis using psychometric tests and information from childhood records.
Stapleton has said that he did not know why he killed Mr Bidve as he just lost control, and a psychological report was carried out to determine any behavioural problems.
Dr Krljes said: "Mr Stapleton has a tendency to be impulsive; bottling up his anger until it suddenly erupts."
She added: "He is quick tempered and can show anger with little or no provocation."
Describing a range of psychopathic characteristics, which include superficial charm, lack of empathy and deceit, Dr Sanya Krljes said Stapleton fell short of being psychopathic.
She added: “A consistent feature of his condition is the tendency to lie to his own advantage.”
The court was told how Stapleton had a lifelong pattern of behaviour which supported the results of the test and showed poor emotional control and extreme antisocial behaviour.
Citing data from school and police reports, Dr Krljes said that although three or more traits out of seven were needed to diagnose a mental disorder, Stapleton had met six of them.
Cross-examining, Brian Cummings QC questioned the usefulness of interview-based testing, claiming that they were 'somewhat artificial' and the defendant could easily have manipulated the results.
He argued that it was not possible to know Stapleton's state of mind at the time he killed Indian student Anuj Bidve on Boxing Day last year.
Dr Krljes agreed that no test could be completely accurate but that taken alongside other data from his childhood as well as how he came across.
She said: “He acted impulsively in the worst imaginable way.”
She did not agree with the prosecutor's assertion that Stapleton's highly impulsive behaviour was simply a way of 'getting a thrill out of something' nor that it amounted to 'attention seeking'.
She added that high scores on the sadistic aggressiveness scale showed a tendency to be abusive towards others, domineering, hostile and intimidating.
Describing people with anti-social personality disorders, she said: "They react with sudden abrupt outbursts that tend to be unexpected and unwarranted."
Mr Cummings referred to Stapleton's attack on an inmate while in custody awaiting trial saying it showed he had a capacity for calculated, controlled violence which conflicted with Dr Krljes finding of impulsivity.
Asked, by the prosecution, if his capacity for planned violence made it unlikely Stapleton had acted in an uncontrolled and impulsive way, Dr Krjles said: “It does not have to be one thing or another.”
"It's like putting a jigsaw puzzle together," she said. "I never said he was 100% impulsive."
Mr Cummings then questioned the findings that the defendant lacked empathy and was emotionally unaware saying that that his 'cocky' and 'flippant' behaviour showed that he did so for the reaction.
The psychologist said that Stapleton had told her 'he liked winding the police up' but that this was also a symptom of his personality disorder.
She said it showed that he was capable of acting to produce an effect but not of appreciating how this made people feel saying: "I don't believe he is able to put himself in another person's shoes."
Stapleton is defending a murder charge on grounds of diminished responsibility.
The case, at Manchester Crown Court, continues today.