What Drugs Do I Need to Know for the MCAT^®?

The AAMC's Psych/Soc content outline names drugs in two content categories:

• Category 6B, Making sense of the environment: under consciousness, it lists "types of consciousness-altering drugs and their effects on the nervous system and behavior" and "drug addiction and the reward pathway in the brain."
• Category 7A, Individual influences on behavior: it lists neurotransmitters and their influence on behavior, and it names "substance addiction" as one of the biological and sociocultural motivators that regulate behavior.

The other two science outlines say less. The Chem/Phys outline doesn't mention drugs or medication at all. The Bio/Biochem outline doesn't name drugs either, but category 3A covers the synapse and "synaptic activity: transmitter molecules," and category 1A covers the types of enzyme inhibition. If a Bio/Biochem passage describes a drug that blocks a receptor or an enzyme, those are the ideas you'd use, and the passage gives you the drug's details.

Foundational Concept 6, the home of category 6B, makes up 25 percent of Psych/Soc. That section has 59 questions, so Concept 6 accounts for about 15 of them (25 percent of 59 is 14.75, an estimate, since the AAMC's shares vary by test form). Drugs are one subtopic inside that concept. The guide to the four sections breaks down the rest of Psych/Soc.

The table below follows the substance use section of OpenStax's Psychology 2e, a free introductory psychology textbook. The Psych/Soc outline assumes one semester of intro psych, so this is the level you're aiming for.

OpenStax marks all four classes as psychologically addicting. It also calls depressants "sedative-hypnotics," so you may see either name in a question.

Stimulants

Stimulants raise heart rate, blood pressure and body temperature. At low doses they increase alertness, cause mild euphoria and reduce appetite. At high doses they can cause agitation, paranoia and hallucinations.

The mechanisms are the part to memorize. Cocaine blocks the reuptake of dopamine, so dopamine stays in the synapse longer. Amphetamines block reuptake too, and they also stimulate dopamine release. Caffeine works on a different system: it antagonizes adenosine, a neurotransmitter that promotes sleep. Nicotine acts on acetylcholine receptors.

OpenStax's amphetamine examples include ADHD medications such as Adderall. If you want the test-day side of that topic, the stimulants and caffeine article covers it. This page is the exam-content version.

Depressants

Alcohol, barbiturates and benzodiazepines act as agonists of the GABA system. GABA has a calming effect on the brain, which is why some of these drugs are prescribed for anxiety and insomnia.

They lower heart rate and blood pressure. Low doses increase relaxation and reduce inhibitions. High doses can cause sleep, motor problems, memory loss, slowed breathing and death.

Opioids

Your body makes its own opioid compounds, which reduce pain and produce euphoria when they bind opioid receptors. Opioid drugs mimic that system, which OpenStax ties to their high potential for abuse.

The body effects in the OpenStax table are decreased pain, pupil constriction, slowed movement of the gut and slowed breathing. High doses can kill through respiratory depression. Pupil constriction is the one effect in the table that no other class shares, so it's a useful clue when a question stem lists symptoms.

Hallucinogens

Hallucinogens cause perceptual changes that range from mild to intense and vary a lot by strain, method of use and person. They can raise heart rate and blood pressure, though that effect may fade over time.

Learn two mechanisms here. LSD and mescaline are serotonin agonists. Ketamine and PCP are antagonists of the NMDA glutamate receptor. OpenStax files marijuana in this class too. If a passage classifies it differently, go with the passage.

For each drug you learn, make one call: does it strengthen a neurotransmitter's effect or block it?

• Agonist: strengthens or mimics the neurotransmitter. Alcohol is a GABA agonist, and LSD is a serotonin agonist.
• Antagonist: blocks the neurotransmitter's effect. Caffeine is an adenosine antagonist, and ketamine is an NMDA antagonist.
• Reuptake blocker: keeps the neurotransmitter in the synapse longer. OpenStax describes cocaine's reuptake blocking as agonizing the dopamine system, so it counts on the agonist side.

Caffeine is a good one to reason through. Adenosine promotes sleep, and caffeine blocks it, so you stay awake. If you can connect a drug's mechanism to its effect in two steps like that, you can handle a drug you've never heard of in a passage.

The outline's second drug item is "drug addiction and the reward pathway in the brain." The pathway has three structures. Here's how they connect, and how the drugs above act on them.

According to NIDA's teaching packet The Neurobiology of Drug Addiction, the neurons of the ventral tegmental area (VTA) contain dopamine, and they release it in the nucleus accumbens and the prefrontal cortex. The packet sums up the effect of addictive drugs in one line: "each drug increases the activity of the reward pathway by increasing dopamine transmission."

The routes differ. Cocaine binds the uptake pumps, so dopamine can't be transported back into the neuron that released it. Heroin and morphine act on neighboring terminals, which signal the dopamine terminal to release more. Nicotine and alcohol activate the pathway as well, "although sometimes indirectly," in NIDA's words.

For the MCAT^®, three names and one neurotransmitter cover it: VTA, nucleus accumbens, prefrontal cortex and dopamine.

These terms show up in addiction questions, and OpenStax defines each one:

• Tolerance: you need more and more of a drug to get the effects you used to get at lower doses.
• Withdrawal: negative symptoms when you stop using a drug, often the opposite of the drug's effects. Stopping a sedative can cause agitation, for example.
• Physical dependence: the body adapts to the drug, so normal bodily functions change and stopping it brings withdrawal.
• Psychological dependence: an emotional need for the drug, often to relieve distress, rather than a physical one.

OpenStax describes substance use disorder in the DSM-5 as a compulsive pattern of drug use with significant negative consequences, and notes that a person often uses more than they meant to. It also points out that craving, a form of psychological dependence, is a recent addition to the criteria.

The "opposite effects" rule for withdrawal saves memorizing. If you know a drug's effects, you can predict its withdrawal: a depressant calms you, so its withdrawal looks like agitation.

The outline lists drug types, their effects on the nervous system and behavior, and the reward pathway. It doesn't list dosages, brand names, drug schedules or receptor subtypes, so leave those out of your notes. Two or three examples per class are enough to recognize a class in a question.

This topic fits on a short deck. Give each drug or class its own cards: class, neurotransmitter, agonist or antagonist, and one hallmark effect. Keep each card to one fact, the way the atomic flashcard method describes, and add a few cards for the reward pathway's three structures and the four dependence terms.

That's the same approach that works for the amino acids: memorize a short list cold, then spend the saved time on practice questions. Content review only pays off up to a point, and the content review trap explains where that point is.

To review consciousness and the rest of Concept 6 next to this material, open the Psych/Soc topics in the PurpleCAT concept library.

Last verified October 30, 2026, against the AAMC's current content outlines for the three science sections.