This system may thus attach an extremely high value to the drug-related behaviors, forming foundation for psychological dependence. Similar deranging influences may be at work with refined high-calorie food products such as sugar or alcohol that takes a less defined position between nutrients and drugs. Their consumable quantities that are currently available far exceed those found in natural products that have historically supplied humans with these nutrient/energy sources (or, as it may be in the case of alcohol in addition to its psychoactive effect, protection of these sources from spoilage). Drug-related negative fitness signals, at least before full possible health consequences of drug use develop, are largely generated by the changeable societal norms, thus having to undergo cognitive processing modulated by numerous individual factors and microenvironment. Therefore, these negative signals only indirectly act upon the measurement system and may not be able to offset the powerful false-positive signal that substance consumption produces directly at the basic neurobiological level.
