Related Clues:

• Drug that dulls the brain
• Drug from poppies
• Poppy derivative
• Morphine, for one
• Narcotic drug
• Endorphin, basically
• Mind duller
• Religion, in an oft-quoted metaphor
• Stimulant's opposite
• It's a downer
• Codeine, e.g.
• Prescription number
• Narcotic or sedative
• Morphine. e.g.
• Dentist's number?