A forensic psychologist on Monday testified that a defendant was experiencing “methamphetamine-induced psychosis” when he fired an automatic rifle, killing two people and seriously injuring a third inside a west Modesto home.
Tou Vang Xiong’s defense doesn’t dispute the fact that he fired the shots that killed his girlfriend, Gao Sheng Her of Merced, and his friend Nhia Yang of Modesto. His defense attorney says his client had used a lot of meth and thought he was firing an AR-15 rifle at demonic tigers July 20, 2009.
Xiong, of Atwater, is on trial accused of two counts of murder, attempted murder and assault with a deadly weapon in the incident at the home in the 1700 block of Radley Place, a few blocks east of Paradise Road. The victims were shot at close range about 5:20 a.m. inside the small, cramped detached room behind the main house.
Forensic psychologist Alex Yufik said he reviewed police reports, the autopsy report, toxicology results, crime scene photos, a video of investigators interrogating Xiong and the defendant’s mental health evaluation. He also questioned Xiong for more than five hours in jail, conducting a clinical interview and a forensic evaluation.
Yufik determined that Xiong has severe anti-social personality disorder, along with substance abuse disorder. He testified that Xiong, around the time of the shooting, experienced the meth-induced psychosis, which results in an intense paranoia.
“They lose touch with reality,” Yufik told the jury about meth addicts experiencing the psychosis.
Previous testimony in the trial has indicated that Xiong spoke of “killing two tigers” moments after the shooting. Yang’s sister testified that “tiger” is commonly used in Hmong culture as a derogatory term for people who are disliked.
The forensic psychologist said in court that some severe cases of meth use result in psychotic behavior, such as delusions; hallucinations of ghosts, demons and angels; and auditory hallucinations such as hearing voices. He said these are the classic symptoms of meth-induced psychosis.
Yufik’s credibility as a meth expert was challenged during cross-examination. He used the fifth edition of a standard guide on mental disorders to reach his conclusion in the Xiong case.
He admitted that the guide on mental disorders has changed and its first edition listed homosexuality as a disorder, and the fourth edition listed Asperger’s syndrome while the latest edition doesn’t list the developmental disorder.
The Xiong trial is the second time Yufik has testified about his findings in court; the first was not long ago in Fresno. He told the jury that sometimes attorneys, on either side, don’t call him to testify because his findings don’t benefit their case.
Yufik is an adjunct professor at the University of Southern California in courses surrounding the psychology of criminal behavior. He also sees patients, conducts forensic evaluations in criminal and civil cases, and works for the State Bar of California at the Lawyers Assistance Program, where he supervises other clinicians and conducts evaluations of attorneys who require monitored recovery and treatment from substance abuse or mental illness.
He explained to the jury the effects of meth on the brain. The drug floods the prefrontal cortex with dopamine, which alters the front part of the brain used for decisions, planning and judgment.
Dopamine is a neurotransmitter that controls the brain’s pleasure center, resulting in the natural good feelings experienced while eating a favorite food, watching a good movie or enjoying a leisurely stroll, for example. Yufik said meth users have a hard time feeling good without the drug unnaturally producing the dopamine.
“It actually rewires the circuitry of the brain,” the forensic psychologist said about meth.
The trial is expected to continue today in Stanislaus County Superior Court.