When Peter Farrelly chose the group, 'Hootie & The Blowfish' to re-record the Orpheus classic "Can't Find The Time", the sheet music that was provided by the song's publisher contained errors in the lyrics. Hootie recorded the song mistakes and all - and it was not until the band invited the songwriter on stage during a show that they learned they had been singing the wrong lyrics.
Charlie's diagnosis of "advanced delusionary schizophrenia with involuntary narcissistic rage" is incorrect. Schizophrenia causes delusions and hallucinations with paranoia. Many people used to believe that schizophrenia resulted in multiple personalities, but this is not the case. He should have been diagnosed with dissociative identity disorder (also known as multiple personality disorder). Further, there is no medication used to treat multiple personalities, although some medications can be used for other symptoms (such as anxiety and depression) that accompany the condition. Treatment of DID involves years of psychotherapy - the disorder cannot be cured by taking a pill as portrayed in the film.