What is the most likely substance abused by a 16-year-old girl who presents with excessive dieting, constant studying, and social withdrawal, along with a BMI of 17 kg/m2 and signs of hypokalemia?

The scenario presents a 16-year-old girl exhibiting behaviors commonly associated with disordered eating and possible substance abuse. Her excessive dieting, constant studying, social withdrawal, low BMI of 17 kg/m², and signs of hypokalemia suggest a specific pattern of substance misuse.

The correct answer points towards diuretics as the most likely substance abused in this context. Diuretics are often misused by individuals trying to lose weight rapidly, as they can lead to significant fluid loss. This can contribute to a low body weight and can explain the hypokalemia, which often results from the excessive loss of potassium through urine due to diuretic use. The girl's signs of extreme dieting, withdrawal, and changes in electrolyte balance further support this conclusion, indicating a potentially serious condition related to her substance use and eating behaviors.

In this case, the other options like alcohol, amphetamines, or laxatives might have various effects but don't align as closely with the specific indicators presented here. Laxatives, while also associated with disordered eating, typically do not lead to hypokalemia as directly as diuretics do when misused in this manner. Thus, the characteristics outlined in her presentation strongly correlate with diuretic abuse, making it the