The UK's Food Standards Agency commissioned a study [...] found "a possible link between the consumption of these artificial colours and a sodium benzoate preservative and increased hyperactivity" in the children;

well-constructed argument.

of course! an onset of hyperglycaemia would quickly follow a high increase in hyperactivity. good answer.

Symptoms of mild overdose may include dry mouth and lips, excitation, fidgeting, irritability, [...]

that would perfectly explain her behaviour. great thinking.

she very well may have mistaken the meth for ice. reasonable judgement.

fair point! would explain the house setting that could be her grandma's.

maybe her pigtails were swapped out? that would explain her malfunctioning.