Los Angeles (CNN) -- A drug addiction expert who testified that Michael Jackson suffered a "quite extensive" drug addiction acknowledged there was no evidence the singer used more painkillers than medically necessary.
Dr. Petros Levounis testified Tuesday and Wednesday for AEG Live in its defense of the wrongful death lawsuit filed by Jackson's mother and children.
Lawyers for the concert promoter want to convince jurors that the singer was a secretive addict responsible for his own death from an overdose of the surgical anesthetic propofol. Their executives had no way of knowing the singer was in danger when he was preparing for his comeback concerts in 2009, they contend.
Jackson lawyers contend AEG Live executives are liable because they negligently hired, retained or supervised the doctor who used propofol to treat Jackson's insomnia as he prepared for his comeback concerts during the last two months of his life.
The conclusion that Jackson was dependent on painkillers was not a revelation, considering Jackson himself announced it when he cut his "Dangerous" tour short to enter a rehab program in 1993.
"If he announced it to the world it's not very private, is it?" Jackson lawyer Michael Koskoff asked Levounis.
"At that moment, he was not secretive," Levounis replied.
Jackson's drugs of choice were opioids, painkillers given to him by doctors repairing scalp injuries suffered in a fire and during cosmetic procedures to make him look younger, Levounis testified.
Labeling Jackson an addict could tarnish the singer's image among jurors, but its relevance to AEG Live's liability is questionable. Opioids played no role in Jackson's death, according to the Los Angeles County coroner. His June 25, 2009, death was ruled a result of an overdose of propofol.
Dr. Conrad Murray told investigators he infused the singer with propofol for 60 consecutive nights to treat his insomnia so he could rest for rehearsals. The judge would not allow Levounis to testify if he thought Jackson was addicted to propofol.
Levounis said addiction happens when a chemical "hijacks the pleasure-reward pathways" in your brain. "You remain addicted for the rest of your life," Levounis testified.
"Michael Jackson's addiction was quite extensive and I have very little doubt that his pleasure-reward pathways had been hijacked and he suffered from addiction," he said.
Levounis conceded he saw no evidence that Jackson used painkillers after he left rehab in 1993 until 2001 or between July 2003 and late 2008.
He said it is not inconsistent for an addiction to go into remission.
Under cross examination Wednesday morning, Levounis conceded that he never saw evidence that Jackson injected himself with narcotics, ever sought or used illegal drugs such as cocaine, meth or heroin, or abused drugs to produce euphoria or get high.
There was also no evidence Jackson used more painkillers than doctors prescribed, he said.
Jackson lawyers have never disputed the singer's drug dependence. In fact, they contend that AEG Live executives, including one who was Jackson's tour manager when he entered rehab, were negligent for paying a doctor $150,000 a month just to treat Jackson. The high salary created a conflict for the debt-ridden Murray, making it difficult for him to say no to Jackson's demands for drugs.
Paul Gongaware, the AEG Live co-CEO who was in charge of Jackson's 2009 "This Is It" tour, was also tour manager for his "Dangerous" tour in 1993. Levounis acknowledged in testimony Wednesday that there was evidence that Gongaware knew about Jackson's painkiller addiction 15 years before his death.
Levounis' testimony about the dangers of a doctor being too friendly with an addicted patient, which he said Murray was, could help the Jacksons' case.
"A very close friendship between an addicted patient and a doctor is problematic," Levounis testified. "It makes it much easier for a patient to ask for drugs and it makes it more difficult for a provider to resist."
The medical records of Murray's treatment of Jackson between 2006 and 2008 -- when the singer lived in Las Vegas -- showed no painkillers prescribed during seven visits. Murray's notes did show he treated Jackson's complaints of insomnia with a sedative in 2008.
Wednesday was the 76th day of testimony in the trial, which is expected to conclude near the end of September.