"He honestly believes somebody gave him something that he could not handle," Peruto said.
He said his client showed what he described as symptoms of mind-altering drugs, such as staying awake for days without getting tired and a foggy memory of the incident. Peruto said Nichols' defense in the case would be involuntary intoxication.
"There was no rhyme or reason for the shooting," he said. "My client actually liked the guys he shot."
Killed in the incident were Joseph Runge, 18, of Glenolden, Delaware County, and Anthony Anderson, 19, of Collingdale, Delaware County. Brian Crow, 19, of Glenolden, was wounded. Tom Crow, Brian's brother, escaped uninjured.
Anderson's 23-year-old brother, Jason, said yesterday that Nichols' planned defense was "absurd" and that none of the victims, who were all friends, was into drugs.
"I know my brother better than I know myself," he said. "He didn't even touch a beer. He was too busy working and going to school."
Peruto said yesterday he was awaiting the results of toxicology reports on the victims to see whether they had any drugs in their systems. Chester County coroner Rodger Rothenberger said the reports are due back today.
Nichols is charged with homicide, aggravated assault and other offenses. He is scheduled for a preliminary hearing on Jan. 25 in Chester County District Court.
Though the Chester County District Attorney's Office may seek the death penalty in the case, police have not yet established a motive for the crime.
When asked about Nichols' involuntary intoxication defense, Chester County District Attorney Joseph Carroll said, "I'm not aware of any evidence to support his claim. We will investigate any defense that we might reasonably anticipate."
After eluding police in an intensive nighttime manhunt, Nichols fled to Philadelphia, where he was captured three weeks later in a Dec. 28 raid of a West Philadelphia apartment.
At the time of the shooting, Nichols was serving 5 1/2 years of probation stemming from a 1998 robbery.
Philadelphia police also said Nichols is charged with robbing a 72-year-old woman in South Philadelphia two days after the KFC shootings.
Jonathan Gelb's e-mail address is jgelb@phillynews.com.