Drugs and jealousy.

In this week’s Throwback Thursday poll, Soaps.com takes readers back to 1978 when “Days of our Lives'” Samantha Evans switched identities with her sister, Marlena…

Theresa Donovan is currently behaving badly in Salem due to substance abuse issues. Back then, Samantha Evans came to town with a serious drug habit and was also very jealous of her older sister, Marlena. She started out stealing from her sister but it wasn’t long before her devious plans escalated and she had Marlena committed to a mental institution. Samantha proceeded to put her acting skills to good use and took over her sister’s life. She was so convincing that even Marlena’s fiance, Don Craig, fell for it.

After Marlena tried to contact Don during an escape attempt, Samantha arranged for her to receive electro-shock therapy to keep her in line. Don became suspicious at one point and eventually Samantha’s plot was exposed. Do you remember what fueled Don’s suspicions? Vote in Soaps.com’s “Days” poll: