Possible Clues:

• Cause of addiction revealed by knight I notice shaking
• Drug — figure drawing it in inhaling poisonous gas?
• Nervous
• Figure straddling single bed is poison
• Poison in it inhaled by figure, as drug
• Toxic substance with carbon monoxide in it, figure will claim
• Drug often smoked
• Material found in tobacco used as an insecticide
• It has an e-delivery option
• Toxic substance in tobacco