Well, I'm very disappointed to find this.
1. One of the more common (and certainly well-known) medications for ADHD is Ritalin, which is methylphenidate. It's mildly related to meth. The long story short is that giving meth to someone with ADHD would not cause them to be able to focus less; rather, to be able to focus more.
2. Studies have shown that sugar does NOT cause hyperactivity in children, whether or not they have ADHD.
I'm saddened to see these incorrect stereotypes about ADHD. As an adult with ADHD, it's part of what makes my life harder than it has to be.