(CNN) - A federal judge ruled Wednesday that accused Arizona Safeway shooter, Jared Loughner, who has been diagnosed with paranoid schizophrenia, is not mentally competent to stand trial. What exactly does that mean?
In order to stand trial, generally it must be determined that the defendant is in touch with reality and has a rational understanding of basic concepts as they relate to the criminal process.
The judge stated Wednesday that Loughner exhibited an "irrational distrust of his lawyers" and "has delusions." These behaviors indicate that he is not lucid and prohibit him from assisting in his own defense at trial.
Mental health experts say determining competency is based on several factors.
First, a one-on-one interview is conducted with the defendant, in which questions are asked about the person's background, family and medical history, for example.
They also collect collateral evidence, which can include documents obtained during the investigation and conversations with people who had been in communication with the defendant.
In Loughner's case, many experts cite his YouTube rants about philosophical and political issues, and reports of inappropriate behaviors by acquaintances.
"Each of these things, by themselves, might not mean much. But when considered together these were certainly red flags for me in thinking about mental illness," says Patricia Zaph, a forensic psychologist with the John Jay College of Justice in New York. Zaph is not involved in the Loughner trial, but says she was not surprised by the ruling.
Finally, psychological evaluations are conducted, which often include an IQ test, and the use of a forensic assessment instrument designed to test specifically for mental illness.
What happens next?
The U.S. attorney general will take custody of Loughner and he will be taken to a hospital for further evaluation. The goal is to restore his competency enough to stand trial.
Schizophrenics have difficulty distinguishing reality from fiction, so psychotropic medications are often used to alter the process of the brains neurotransmitters and reduce symptoms, like feelings of agitation, hallucinations and delusions.
Loughner will be reevaluated again in a few months, after being treated in the federal facility.
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