The DSM-5 groups ten designated classes of drugs into a group called “substance-related disorders.” What is the rationale for this grouping? a. These drugs all share the ability to activate the neural circuitry that mediates “reward.” b. These drugs all can produce a strong physical dependence and withdrawal. c. Studies have shown that addiction to these drugs is always fatal. d. Although these drugs all activate very different circuitry, they also share abuse potential.
The correct answer and explanation is:
The correct answer is: a. These drugs all share the ability to activate the neural circuitry that mediates “reward.”
Explanation:
The DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition) categorizes substance-related disorders into ten distinct drug classes, which include substances like alcohol, cannabis, cocaine, opioids, and more. The rationale for grouping these substances together under the umbrella of “substance-related disorders” lies primarily in their shared impact on the brain’s reward system. These drugs, despite their diverse chemical properties and effects, all activate brain circuits involved in reward, pleasure, and reinforcement, particularly the mesolimbic dopamine system.
The neural reward system is responsible for feelings of euphoria and pleasure, which can lead to the reinforcing cycle of drug use and, over time, the potential for addiction. When a substance activates this system, it can lead to cravings and compulsive use. This shared capacity to stimulate the brain’s reward pathways forms the basis of substance use disorders, as repeated use can result in tolerance (the need for more of the substance to achieve the same effect) and dependence (relying on the substance to feel normal or to avoid withdrawal symptoms).
Option b is incorrect because while many substances can lead to physical dependence and withdrawal, not all substances in the DSM-5 classification induce this kind of physical dependence. For instance, cannabis does not typically lead to severe physical withdrawal symptoms, unlike opioids or alcohol.
Option c is not accurate since addiction to these substances is not always fatal. While overdose or long-term health consequences may increase the risk of death, addiction itself does not always result in fatality.
Option d suggests that these drugs share abuse potential, which is partially correct, but the more specific rationale lies in their shared effect on the brain’s reward system, as outlined in option a.