Depending on the national context, substance abuse can include excessive consumption of alcohol (including commercial or home-brewed), consumption of illegal drugs, misuse of prescription medications and misuse of consumer products in order to achieve an altered state (e.g., sniffing petrol). It is important that measures of substance abuse include frequency of consumption or intoxication and amount consumed within a typical consumption period. This could be defined as drinking to get drunk or drinking a set amount, such as five or more drinks on one occasion.