BBC News reports that Smith's psychiatrist Khristine Eroshevich and ex-partner Howard K. Stern were found guilty of conspiring to give the former Playboy star excessive amounts of prescription drugs.
Eroshevich was also convicted of prescription drug fraud. She and Stern were cleared of other charges.
Dr Sandeep Kapoor, who was tried alongside Eroshevich and Smith, was acquitted on all counts.
All three defendants had stood accused with conspiracy, excessive prescribing of opiates and sedatives to an addict and fraudulently obtaining drugs by using false names.
Earlier in the day, the jury had asked Superior Court Judge Robert Perry about the process should they be unable to reach a verdict on "a count or an object crime".
The verdicts were returned after the judge had urged the jury not to hesitate to declare a hung jury if a verdict could not be reached.
Smith died of a prescription drug overdose in February 2007, aged 39.