It might surprise people that Psychedelic Psychiatrist is a song of a more topical nature. Specifically it was about someone who was a very big figure in the news starting in the late 1960s - Timothy Leary.
Although Timothy Leary was characterized in the press as a kook and a flake and possibly dangerous, he was actually a serious researcher into the therapeutic use of psychedelic drugs in controlled conditions. Timothy Leary was a bit ahead of his time and this area is once again being looked into, and is showing promise with a number of psychiatric conditions.
Eugene, like most people, had no idea what psychedelic drugs were, what they did, and thanks to the news reports at the time, saw Timothy Leary as a suspicious character and a bit of a fraud that had to be in it for the money which Eugene expressed with the line - 'he leads you on and on until your money's gone'
The mocking tone and the piano arrangement which will remind people over 60 of the style of the comedy songs that were around at that time, make this a fun bouncy song.
- and of course, the song is as goofy as its title.