Subjects were randomly enrolled into three groups: risperidone group, combination of risperidone and benzhexol group and combination of risperdone and alprazolam group.
"Mr.Heath Ledger died as the result of acute intoxication by the combined effects of oxycodone, hydrocodone, diazepam, temazepam, alprazolam, and doxylamine," the office said in a short statement.