Assessing whether a person is psychotic

Many factors are taken into account when deciding whether or not a person is psychotic, it has been noted. Professor Simone Fox of the psychology department at the University of London - founded in 1836 - and member of the British Psychological Society explained a team of mental health professionals all take part in such assessments, the BBC reports.

These can include psychiatrists, occupational therapists, nursing staff and psychologists and as well as round-the-clock monitoring, a person's medical history is also considered.

Professor Fox was speaking in response to news that Anders Behring Breivik, who has admitted to killing 77 people in July this year, has been declared psychotic by psychiatrists in Norway - meaning he is more likely to face detention in a mental institute than prison.

According to Professor Fox, analysts look at how a person is presenting on a ward, their behaviour at night and the things they say, adding: "It's to see if there's a consistent picture, because what they are saying at interview could be for the sake of a trial."