Beings of smokeless fire, older than Islam, folded into its theology, then flattened into a lamp and three wishes.
Documented
Older than the Quran
Jinn appear in pre-Islamic Arabian belief and inscriptions, then receive their own chapter, Surah al-Jinn, as created beings with free will, communities, and judgment. The root j-n-n means to hide.
Assessment: Documented in scripture and epigraphy. The hidden ones have an unusually visible paper trail.
Stories
The lamp was late
Aladdin and his lamp are absent from the oldest manuscripts of the Thousand and One Nights; the tale was added to the French translation by Galland in the early 1700s, allegedly from a Syrian storyteller. The wish-granting lamp-genie is a late, dressed-up descendant.
Assessment: Documented textual history. The most famous jinn story is an insertion, and everyone kept it.
Interesting claims
The night visitor has a clinical name
The deflationary claim: the jinn encounter is sleep paralysis, the chest-pressure, the presence in the room. Cross-cultural sleep research finds the same experience wearing the local spirit's clothes, from jinn to the Newfoundland old hag.
Assessment: The sleep research is solid science. It explains the visitation; it does not explain why the hidden ones needed a name for it first.
Sources and further reading
Quran 72, Surah al-Jinn
Pre-Islamic Arabian inscriptions on jinn
Galland's 1704 French translation note, the Aladdin insertion
Cross-cultural sleep paralysis research on nocturnal visitation
Worth asking
Every culture's bedroom demon matches. Were they all wrong, or were they all comparing notes?