Which addictive drug tells the body to stop producing natural endorphins?

Opium is the addictive drug that stop natural endorphins produced.  This depressant/narcotic made from the opium poppy that has pain-relieving and euphoria inducing properties and is highly addictive, Mimics endorphins and causes body to stop producing endorphins.  Endorphins, the neurotransmitters that naturally deaden pain sensations. Slow down the nervous system and mixing with other depressants like alcohol can be deadly. Derived from opium.

her next move would be to use agarose gel electrophoresis to separate the dna molecules of varying length and create a dna fingerprint.