Assertion: nightmare's cause | /r/HasProperty | physical
Facets:
Source sentences:
text: Nightmares can have physical causes such as sleeping in an uncomfortable position or having a fever, or psychological causes such as stress or anxiety.
text: Nightmares can have physical causes such as sleeping in an uncomfortable or awkward position, having a fever, or psychological causes such as stress, anxiety, and ingestion of opioid drugs used in pain killers such as oxycodone and hydrocodone.