What does unlawful possession of a controlled substance entail?

Unlawful possession of a controlled substance primarily refers to the possession of a substance that is classified under the controlled substances schedules without appropriate legal authorization. In this context, a usable quantity of a substance categorized in Schedule I or II indicates that the individual is in possession of drugs that are highly regulated due to their potential for abuse and dependency. Schedule I substances are those seen as having no accepted medical use and a high potential for abuse, while Schedule II substances may have accepted medical uses but still require strict regulation due to their risks.

Possessing these substances without a valid prescription or permission is contrary to the law, hence constituting unlawful possession. Legal prescriptions and medical use scenarios do not apply to this situation, as they would indicate lawful possession and usage.