Drugs classified as Schedule I are characterized by which of the following?

Drugs classified as Schedule I are characterized by having a high potential for abuse and no accepted medical use in the United States. This classification signifies that these substances are considered dangerous and are often associated with severe risks of addiction and abuse. Because they lack any recognized therapeutic benefits, Schedule I drugs are strictly regulated, and research involving these substances typically requires special permission from the government.

The rationale for this classification stems from concerns about public health and safety; Schedule I drugs pose significant risks without providing legitimate medical benefits. Common examples include substances like heroin and lysergic acid diethylamide (LSD), which are well-known for their high abuse potential and the absence of approved medical uses.

The other potential classifications outlined in the question, which imply accepted medical uses or low abuse potential, do not apply to Schedule I substances and thus help further clarify the criteria that define this category.