Raoden had begun seeing a second, red Maximillian sitting on his other shoulder.
The two Maximillians often gave contradictory advice on a myriad of issues.

During Raoden’s forced commitment in Harborside Hospital for psychiatric evaluation, he suddenly realized he was no longer able to communicate telepathically with Maximillian.

Having done drugs for the first time in a whole, Red Max appeared again and had begun trying to convince Raoden to buy ingredients for the Hat-Dog spell, but through the drug induced stupor, Raoden managed to find out that these components could be used in a spell to summon forth a demon.
Excusing himself from buying the components due to their steep price, Raoden slapped Red Max who claimed Kitty’s soul was stuck in the nine hells.
At that point Red Max disappeared and Raoden went and used the ritual he found to restore his connection with Real Max TM.

The current theory is there might be a connection between Red Max, the Vampire roaming Baldur’s Gate, and maybe the Preacher.