I believe the "meth" addiction for her comes in the form of her prescription Adderal, which is a brand name drug that combines (primarily) amphetamine and dextroamphetamine to treat ADHD.
Methamphetamine and Adderall are similar but not chemically the same. Adderall is a dextroamphetamine salt combo. The article mentions “crystal” meth. If she’s addicted to methamphetamines, it’s not in the form of the prescription drug Adderall.
The person who leaked the information may have inadvertantly said “methamphetamine” instead of “amphethamine” and from there the author drew a conclusion of “crystal meth.”
I’ve heard her father say that she’s addicted to prescription drugs. If that’s true, it’s amphethamines and not methampethamines - unless she’s cooking crystal meth from her Adderall prescription, which I doubt because meth labs smell really, really bad and she’d have been caught by now.