Final answer:
Grace's symptoms of yellow skin, suppressed appetite, and high blood pressure indicate that she is most likely abusing alcohol. Alcohol is a depressant that can damage the liver and affect cardiovascular function.
Step-by-step explanation:
The symptoms described in the question, such as yellow skin, a suppressed appetite, and high blood pressure, suggest that Grace may most likely be abusing alcohol. The yellowing of the skin can be a sign of jaundice, which is often caused by liver damage due to excessive alcohol consumption.
Moreover, ethanol, which is present in alcoholic beverages, is a psychoactive substance known as a depressant, which can have various effects on appetite and cardiovascular function, potentially explaining the high blood pressure.