Robin Williams had Parkinson’s tremor, likely suffered from hallucinations before death

Robin Williams first began experiencing Parkinson’s-like symptoms in 2011 that included tremor in his left arm and restrictions of his left hand movements, but he wasn’t diagnosed with the disease until Nov. 2013, a pathology report about the famed comedian reveals.

The “Mrs. Doubtfire” actor saw some relief of his symptoms with a drug called pramipexole, and he began taking another called levodopa shortly before he committed suicide in August. Both drugs list hallucinations as a side-effect.

At the time of his death, 63-year-old Williams was also suffering from diffuse Lewy Body dementia, which can also cause hallucinations.

“It is important to note that patients with diffuse Lewy Body dementia frequently present with Parkinsonian motor symptoms and… depression and hallucinations,” explains a pathology report obtained by FOX411.

Back in May, Lewy Body dementia made headlines when it was revealed former radio host Casey Kasem was suffering from the neurodegenerative disease before his death in June at the age of 82. Kasem’s kids revealed he was unable to speak prior to his death.

TMZ reported that friends and family of Williams believe Lewy Body dementia was the main factor that led to his sudden suicide in August.

Still, in addition to the Parkinson’s and dementia, Williams had a history of depression, paranoia, compulsiveness and anxiety.

His wife, Susan Williams, revealed to police his paranoia had been acting up before his death, and the day before he died he put several watches into a sock and gave them to an unidentified acquaintance for safe keeping.

The Oscar-winning actor made audiences laugh with his stand-up comedy and hit films. He was known playing the loveable Mork in “Mork & Mindy,” and for his more serious roles in films such as “Good Will Hunting” and “Patch Adams.”