Just an idea that worked well for my bff: she is from a unique cultural background and so she talked about that in her essay #1. Programs LOVE LOVE LOVE diversity, so if you can work that angle, work it.
Also, keep in mind that what internship committees consider bizarre is way different from what NORMAL people consider bizarre.
🙂 That's why I suggest the stodgy old prof reading the essay.
The whole situation is frustrating really: you want to be unique but unique in a sort of boring way.
Also, it may go w/o saying, but NEVER mention personal or family mental health struggles in your essay in any way. There is still much inappropriate/unjustified/unfair prejudice from people who should know better. You don't want to be dismissed as a person who is becoming a psychologist to fix his own issues.
Best of

,
Dr. Eliza