Some researchers have suggested that Incubus/Succubus attacks are related to strong sexual repression. As noted above, tales of Incubi and Succubi were originally linked more with monks and nuns – two groups of individuals who have sworn celibacy. As the nature of the attacks is sexual and has been associated with erotic dreams and/or bodily sensations, there is a belief by some that victims of the attacks feel sexual desires that they refuse to acknowledge, thus their subconscious plays out sexual feelings at night when it can run rampant. There is also a belief that the encounters are hallucinations or delusions that emerge from the repression of sexual desires.