In general, the more predictable and frequent the dosing, the more addictive a drug will be. Three Laws of Psychopharmacology The very definition of an addictive drug is one that stimulates the mesolimbic pathway, but there are three general axioms in psychopharmacology that also apply to all drugs: All drugs act by changing the rate of what is already going on. All drugs have side effects. The brain adapts to all drugs that affect it by counteracting the drug’s effects.
