Hypnagogia is not a mental illness, but it can be a symptom of certain psychological conditions, such as sleep disorders and dissociative identity disorder. It is also associated with sleep paralysis and lucid dreaming, which are sometimes accompanied by strange sounds, images or sensations. Hypnagogic experiences may be uncomfortable at times and can interfere with one's ability to fall asleep or stay asleep; however, for most people, these hallucinations are considered harmless. In some cases, hypnagogic episodes may lead to increased creativity and mental acuity during the day.