Hamilton's defense team is seeking to prove that on the night of Sept. 14, 2006 when Quick was murdered, Hamilton was suffering from untreated schizophrenia and a psychotic break, complicated by alcohol or drug use. Hamilton, 30, is pleading not guilty by reason of insanity.
Several pieces of evidence found at the crime scene and belonging to Hamilton contain DNA evidence connecting Hamilton to Quick's rape and murder, detectives and crime lab scientists testified.
The District Attorney's Office is seeking the death penalty against Hamilton. However, it is illegal in Nevada to execute the mentally ill.
On the morning of Sept. 15, 2006, Quick’s mother found her daughter's body in the teen’s bedroom of their Marina Village apartment near the Sparks Marina. The teenager bled to death from a wide, 2-inch-deep gash to her throat.
On Monday, Neuropsychologist Dr. David Schmidt answered a barrage of questions and objections throughout Monday morning by Deputy District Attorney Luke Prengaman and Public Defender Maizie Pusich, whose office hired Dr. Schmidt to assist in Hamilton's defense.
After conducting neuropsychological testing, observation and interviews on Hamilton in November 2006 and January 2008, Dr. Schmidt concluded that Hamilton suffered from paranoid schizophrenia. The incurable disease often includes delusions, and visual and sound hallucinations, where "voices" are incessantly commanding the mentally ill person to do things, Dr. Schmidt said. Unlike other types of schizophrenia, paranoid schizophrenics are much more likely to display violent behavior during their psychotic breaks, but can live nearly normal lives in between these breaks, Dr. Schmidt said.
"In paranoid schizophrenics experiencing a psychotic break, the risk of violence is significant, and it's usually against family and friends," Dr. Schmidt said.
Dr. Schmidt was not allowed to reveal the contents of his interviews with Hamilton, because Judge Connie Steinheimer ruled that Hamilton's perception of that night is hearsay, and that Hamilton was allowed to testify himself, but chose not to do so.
Hamilton had voluntarily discontinued his anti-psychotic medication, Geodon, for about a month during Dr. Schmidt's second assessment of him. Dr. Schmidt used the same series of tests during both visits.
"When Mr. Hamilton was off of his anti-psychotic medication, he experienced more auditory hallucinations, more feelings of paranoia and agitation, a little more vigilant, displaying signs of feeling vulnerable and the sense that things are not as they should be," Dr. Schmidt said.
Dr. Schmidt looked for inconsistencies between the two test days, and said "a lot of those feigning mental illness overshoot the mark," which can be seen in test results. Dr. Schmidt also admitted that psychological testing is not an exact science, and no one can know for certain whether someone actually thinks they are hearing voices and seeing hallucinations.
"There is no test in the world that can provide verification of hallucinations and private thoughts," Dr. Schmidt said. "Every day in my profession, we rely upon a patient's statement of symptoms to assess their illness. I am quite confident he did not attempt to fake his mental illness."
When questioned by prosecution, Dr. Schmidt also admitted that his first personality test on Hamilton was invalid because of the large number of false positive results, and that a second try at the same test was just above what was considered normal test results for accurate mental illness assessment. However, the doctor said the test creators claim a second bad test should not be considered invalid.
In addition, Dr. Schmidt testified that he had conducted a forensic psychological assessment, but admitted he did not talk to Hamilton's close friends and did not view videos of Hamilton's questioning by police.
In sharp contrast to Dr. Schmidt's diagnosis of schizophrenia, Dr. Ole Thiensaus, a forensic psychiatrist hired by the prosecution and who had previously treated Hamilton at the Washoe County Jail, said Hamilton did not show signs of psychosis during a 50-minute interview.
"I think it's extremely unlikely he suffers from schizophrenia," Dr. Thiensaus said, adding that diagnosis of mental illness of inmate patients at the jail, "is less reliable than in other settings because of the time factor; they rely very much on what the patient tells you, and is largely medication-treatment based."
The prosecution called a number of additional witnesses to question if they thought if Hamilton was mentally ill, including Hamilton's friend Odest Mitchell, and Hannibal Williams - Hamilton's friend and husband of Quick's sister, Jhana Williams. Neither Mitchell nor Hannibal Williams believed Hamilton to be mentally ill, and said he was sociable within his circle of friends.
Also, Dr. Robert Hiller, who was requested by the court to evaluate if Hamilton was mentally competent to stand trial back in June 2007, said Hamilton did not do well on a test that assesses whether someone is faking poor mental function.
"We have a tendency to remember what we haven't seen," Dr. Hiller said. "Even people with severe brain damage do very well on the test. Mr. Hamilton did extremely poorly. No clinical group scores that poorly; even people with dementia could not have done so poorly."
Dr. Hiller said, after a one-and-a-half hour interview and testing that Hamilton "was presenting himself as someone who had a mental illness. I felt that he was both malingering (making false representations) and competent (to stand trial)."
When questioned by defense, Dr. Hiller admitted that the test did not test for mental illness, and that he had written on his report that it was possible that Hamilton responded extraordinarily well to his anti-psychotic medication.
The trial is expected to conclude on Tuesday or Wednesday, with jury deliberation directly following that. Judge Steinheimer is considering whether to allow the testimony of a victim that Hamilton was convicted of raping two weeks before Quick's murder, to testify about Hamilton's mental state at the time.