
Now Playing: Researchers working on possible depression blood test
Now Playing: What to know about the popular ‘carnivory’ diet
Now Playing: What parents should know about youth football and heat strokes
Now Playing: New drug shows possible promise for those with Alzheimer’s
Now Playing: Bayer to no longer sell permanent birth control implant Essure
Now Playing: Demi Lovato hospitalized for a suspected overdose: Source
Now Playing: Mother leads new lawsuit saying Juul is addicting kids to nicotine
Now Playing: 4 kind of Goldfish crackers recalled due to possible salmonella risk
Now Playing: What is hand, foot and mouth disease?
Now Playing: New study calls on doctors to screen for depression in new dads
Now Playing: Olympic swimmer suspended after Instagram post
Now Playing: 10 moves to get a body like Britney Spears
Now Playing: ‘GMA’ Hot List: Food additives pose health risks for kids: Report
Now Playing: Is your sunscreen expired? Here’s what you need to know
Now Playing: Are the chemicals in food coloring bad for children?
Now Playing: Study shows pregnant women have increased risk for heart attack
Now Playing: What these parents want you to know about caring for a child diagnosed with PANDAS
Now Playing: Doctor explains PANDAS: How the psychological, neurological condition impacts brain
Now Playing: Bystander rescues baby from hot car
Now Playing: What to know about heat stroke