Dr. Sandeep Kapoor, Dr. Khristine Eroshevich and Howard Stern are accused of illegally providing Smith with sedatives and pain killers.
The defendants have pleaded not guilty to charges they conspired to illegally prescribe drugs to Smith.
Defense lawyers argue that their clients did not know Smith was a drug addict and that they even tried to save her in her waning years, including the time when she gave birth to a daughter and lost her adult son to a drug overdose.
The judge is also uncomfortable with the prosecution's argument that the doctors prescribed Smith drugs under assumed names, because witnesses are likely to say that it's normal in the celebrity community for doctors to do that.
The former Playboy model died of a drug overdose in 2007.
The Associated Press contributed to this report.