CENTENNIAL — The word “sanity” has little meaning in the clinical world of mental health professionals, but it looms large in the criminal trial of James Holmes.

His attorneys and their experts say he is schizophrenic, and a psychiatrist who evaluated him on behalf of the state concluded that Holmes suffers from mental illness.

But under Colorado law, that’s not the question jurors must consider when a defendant such as Holmes pleads not guilty by reason of insanity.

For Holmes, two of the central questions are whether he knew what he was doing was legally wrong and whether he knew what he was doing was morally wrong — not whether he was mentally ill or capable of planning the attack.

“A psychiatrist who does forensic work understands the word, for example, ‘insanity’ has a much different meaning to a criminal court than it does at a cocktail party or whenever talking with other psychiatrists,” Dr. William Reid said during Holmes’ murder trial. “Psychiatrists rarely use the phrase sanity or insanity.”

Reid spent 22 hours interviewing Holmes in July as one of two state-appointed psychiatrists who were asked to determine whether he was sane or insane at the time of the shooting.

Holmes is accused of killing 12 people and injuring 70 in the July 20, 2012, attack at the Century Aurora 16 movie theater. He could face the death penalty if convicted.

During the first day of his testimony, Reid said he believes Holmes was capable of knowing that what he was doing was wrong when he opened fire inside the theater. Eighteenth Judicial District Attorney George Brauchler has said the other court-appointed psychiatrist also found Holmes was sane.

But defense attorneys say two additional experts they asked to evaluate Holmes found he was so severely mentally ill that he was not in control of his thoughts or actions.

“When he stepped into that theater in July of 2012, he was insane,” defense attorney Daniel King said in opening arguments. “He no longer lived in a world we live in.”

King said Holmes was operating under the powerful delusion that he would increase his worth by killing others. Almost three years after the shooting — and despite two years of medication — Holmes still believes that delusion, King said.

Prosecutors, however, argue that in the same time Holmes’ attorneys say he was in a psychotic spiral, he was still able to patiently amass an arsenal of weapons and meticulously plan his attack. Those plans are detailed in a notebook Holmes mailed hours before the shooting to a University of Colorado psychiatrist who treated him.

But the ability to plan and function does not always indicate that someone is sane, said Dr. Richard Martinez, a forensic psychiatrist and director of the forensic psychiatry program at CU’s School of Medicine.

“People with mental illness are not totally fragmented to the point that they don’t take care of certain needs and activities of daily life,” Martinez said. “The issue of planning and deliberation toward an end, like a terrible tragedy such as this, in and of itself does not mean that reasoning and rationality are intact.”

The notebook also contained Holmes’ estimates on how long it would take police to get to the theater. Experts have told The Denver Post that those entries could be particularly damning for Holmes, because they show he knew what he was doing was wrong.

Under Colorado law, a person can know that what he is doing is legally wrong and still be found insane, Martinez said. Prosecutors must also prove the defendant knew that what he was doing was morally wrong.

A 1992 Colorado Supreme Court decision established the fine line for determining whether someone operating under a fixed set of delusions knows his actions are morally wrong. If someone commits a crime he knows is socially unacceptable but does so anyway because his delusions are severe, he may be found legally insane.

Stephanie Rochester, for example, was found to be legally insane after she killed her 6-month-old son, Rylan, in 2010. The Superior mother knew that killing her son was morally wrong but did so anyway because she believed the delusion that Rylan had become possessed and that killing him would end the infant’s suffering, according to the Boulder Daily Camera.

But simply believing in a delusion does not make someone legally insane, Martinez said.

In 2012, Ari Liggett poisoned his mother and dismembered her body because he believed she was mentally ill. An Arapahoe County jury — the same district where Holmes is being tried — took less than eight hours to reject Liggett’s insanity plea.

It is rare that someone who plans his crime is found insane.

Deciding whether a defendant is faking symptoms, suffering from mental illness or is legally insane is a difficult, case-by-case evaluation, said Dr. Neil Gowensmith, who teaches at the University of Denver and works at its Forensic Institute for Research Service and Training. Evaluators will look for several things, but one key element is whether the defendant uses cues that a sane person would use to guide his decisions.

Historically, defense attorneys face long odds in persuading a jury to find someone not guilty by reason of insanity. Only about 1 percent of all felony cases nationwide involve a plea of not guilty by reason of insanity; the plea is successful in only about a quarter of those cases.

The adversarial process of a trial often forces prosecutors and defense attorneys to create polarizing stories that can distort “the reality of the mentality of the defendant,” said Martinez, who has completed court-ordered evaluations for several defendants, including Rochester.

“The law, unfortunately, only gives us two garages to park the car in. You either park the car in the insanity garage or you park the car in the sane garage,” Martinez said. “Unfortunately, the law and public policy have not effectively addressed the issue of mental illness between those two extremes.”

Failures to do so has stalled discussions about the causes of mental illness, Martinez said.

Gowensmith also worries that cases such as Holmes’ — in which people who have or claim to have mental illness commit violent acts — will cause the public to draw unfair correlations between violent crimes and mental illness.

“People with mental illness are no more violent than people without mental illness. They’re no more likely to commit crimes than people without mental illness,” Gowensmith said. “Even if (Holmes) is found guilty, people will be tainted.”

Jordan Steffen: 303-954-1794, jsteffen@denverpost.com or twitter.com/jsteffendp