Was Michael Jackson addicted to the pain medicine Demerol? Dr. Robert Walderman, an addiction expert, says he certainly believes the pop star was addicted to Demerol in the months leading to his death.

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“I believe there is evidence that he was dependent on Demerol, possibly,” said Waldman. According to USA Today, Walderman suggests that Jackson was also addicted to opioids the month before he suddenly died.

A key symptom of Demerol withdrawal is insomnia, says Walderman, which would explain Jackson’s dependency on propofol.

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The defense team has two witnesses left to call, after bringing five character witnesses to the stand yesterday.

Closing arguments are expected to begin next week.