Which of the following drugs would be most likely to result in a fatal overdose? A. LSD B. mescaline C. marijuana D. sedatives

First, let's briefly understand each drug and their possible effects: - LSD (Lysergic acid diethylamide): A psychedelic drug known for its psychological effects which include hallucinations, synesthesia, and ego dissolution. - Mescaline: A psychedelic drug derived from the peyote cactus, known for its hallucinogenic effects similar to LSD, but it is less potent. - Marijuana: A psychoactive drug derived from the Cannabis plant, used for recreational and medical purposes. It contains the mind-altering compound called THC (tetrahydrocannabinol). - Sedatives: Central nervous system depressants that are used to induce calm, relaxation, and sleep. These include benzodiazepines, barbiturates, and some sleep medications.

When assessing a drug's potential for a fatal overdose, it's crucial to know how much of the substance can be lethal. This is often measured using the concept of LD50 (lethal dose for 50% of the population). - LSD: It doesn't have a specific established LD50 for humans, but studies suggest it to be extremely high and improbable to reach by accident. - Mescaline: Similar to LSD, mescaline has a very high LD50. It's less potent than LSD, so the risk of a fatal overdose is even lower. - Marijuana: It has been considered virtually impossible to die from an overdose of marijuana due to the extremely high amount of the drug needed to reach its LD50. - Sedatives: Different sedatives have different LD50 levels, but they are generally lower than the substances mentioned above. An overdose of sedatives can cause respiratory depression, coma, and death.

Comparing the LD50 and effects of the four mentioned drugs, it becomes clear that sedatives have the lowest LD50 and the highest risk for a fatal overdose.

Based on the analysis, the drug most likely to result in a fatal overdose is: D. sedatives