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29/09/2026
From personal use to drug trafficking offences in chemsex contexts: drug quantity thresholds established in INTCF reports
abstract
Article 368 of the Spanish Criminal Code criminalises drug trafficking, and the quantity seized serves as circumstantial evidence of the substance’s intended use. In practice, the assessment of the evidence relies on dose tables whose de facto authority derives from the Spanish National Institute of Toxicology and Forensic Sciences (INTCF). Through a critical analysis of legal and documentary sources, this article examines the consequences of using the quantities set out in certain INTCF reports as a criterion for distinguishing possession for personal use from possession for trafficking. These reports, obtained through freedom-of-information requests after appeals against initial refusals of access, set quantities without a legislative or regulatory procedure or a scientific rationale against which particular values can be assessed. It examines the initial report of 18 October 2001 and its supplements; the treatment of γ-butyrolactone (GBL) as equivalent to γ-hydroxybutyric acid (GHB) in expert reports after GHB esters and ethers were removed from Spanish controls in 2006; the extension of methamphetamine reference quantities to synthetic cathinones; and the conversion of single-dose ketamine amounts into daily consumption quantities. It concludes that certain expert reports function as criteria with criminal-law consequences for people who use drugs and proposes reserving the setting of reference quantities to a legislative or regulatory process, using traceable methods and scientific evidence.
Keywords:
INTCF, drug quantity thresholds, GBL, chemsex, principle of legality, harm reduction.
Received date
13/05/2026
Accepted date
11/09/2026