Michael Lohan complained that the 'Mean Girls' star who recently underwent a prison and rehab stint, was misdiagnosed by her doctors.
Lohan's lawyer Lisa Bloom confirmed that she had asked the medical board to look into the physicians' prescription practices and the investigation is underway, reported CNN online.
Bloom lodged a complain with the California Attorney General against "the unscrupulous doctors (who) over-prescribed Lindsay."
"The Medical Board is investigating and Michael and I are co-operating with them," said Bloom.
According to medical reports Lindsay was taking Dilaudid, Adderall, Nexium, Zoloft, Trazodone and Ambien for various medical conditions when she checked into a rehab facility following a prison spell this summer.
The medicine experts diagnosed her with Attention Deficit Hyperactivity Disorder (ADHD) and directed a remedy that has put her health in an alarming state, said the lawyer.