Drugs and Health
At a family party, at the corner store, or on the sidewalk outside school, it's easy to see alcohol and cigarettes. Just because a substance is easy to buy doesn't mean it's harmless to your body, and even less so while your brain is still finishing its development. On this page you'll see what addictive substances do to the nervous system and why it's best to avoid them.
What a drug is
A cup of coffee in the morning wakes you up, an allergy syrup makes you sleepy, and a beer lowers your inhibitions: very ordinary substances change how we feel and act. What do they have in common that lets them alter our body this way?
Explain what a drug is from the point of view of its effect on the body, and classify these substances as legal or illegal drugs in Mexico: alcohol, cannabis, tobacco,…
Explain what a drug is from the point of view of its effect on the body, and classify these substances as legal or illegal drugs in Mexico: alcohol, cannabis, tobacco, cocaine, caffeine.
Three main groups based on their effect
A beer slows your reflexes and makes you sleepy, an energy drink speeds up your heart, and certain substances make people perceive lights or sounds that don't exist. How does science organize substances with such different, even opposite, effects on the nervous system?
The diagrams represent the effect of the three main groups of drugs on nervous system activity: the dashed gray line shows normal activity and the coloured line shows…
The diagrams represent the effect of the three main groups of drugs on nervous system activity: the dashed gray line shows normal activity and the coloured line shows activity after consumption. Name the group (depressants, stimulants or hallucinogens) that corresponds to each diagram (A, B and C), explain what each one consists of, give an example of each group, and reason why this classification does not take into account whether the drug is legal or illegal.
Tolerance and dependence
Someone who starts with one cup of coffee a day often needs two or three after a few months to feel the same effect, and if one day they have none, they get a headache. Why does the body ask for more and more, and respond with discomfort when the substance is missing?
Explain what it means for a drug to cause dependency, and distinguish, using an example, between physical dependency and psychological dependency.
Explain what it means for a drug to cause dependency, and distinguish, using an example, between physical dependency and psychological dependency.
Explain what tolerance and withdrawal symptoms are, and how these two phenomena contribute to an addicted person consuming increasingly more of a drug and finding it so…
Explain what tolerance and withdrawal symptoms are, and how these two phenomena contribute to an addicted person consuming increasingly more of a drug and finding it so difficult to quit.
In the brain reward circuit, neurotransmitters like dopamine generate pleasurable feelings. A psychoactive drug blocks the reuptake of dopamine, causing its…
In the brain reward circuit, neurotransmitters like dopamine generate pleasurable feelings. A psychoactive drug blocks the reuptake of dopamine, causing its concentration in the synapse to multiply artificially.
- a) Predict how the postsynaptic neuron membrane will respond (by decreasing or increasing the number of dopamine receptors) after weeks of continuous consumption to defend itself from this excessive stimulation. Justify why this cellular mechanism explains the phenomenon of tolerance.
- b) Based on your previous answer, deduce why, when the person abruptly stops consumption, they experience intense physical and psychological discomfort (withdrawal syndrome) during normal daily activities.
Alcohol, tobacco, and vapes in adolescence
Vapes are not "just vapor"
The aerosol from a vape is not water vapor. It is a mixture of very fine droplets that can contain nicotine (addictive), propylene glycol and glycerin, flavorings, metals such as nickel or lead that come off the heating coil, and other toxic substances. When inhaled, it irritates and damages the epithelium of the airways: they become inflamed and the cilia that clean the bronchi work less well, which promotes infections and chronic cough. In addition, studies indicate that teenagers who vape are more likely to move on to traditional cigarettes later, so the vape is not a "safe" way to quit smoking.
Implications for the individual and society
Addictive substances don't only affect the body. In health: damage to the brain, liver, lungs, and heart, and risk of accidents. In sexuality: they lower judgment and control, and increase unprotected sex, with risk of STIs and unplanned pregnancies, as well as situations in which there is no clear consent. In the economy: using costs money every week, and dependence affects school and work. In society: traffic accidents, violence, and family conflicts. For all these reasons it's best to avoid them, especially now that your brain is still forming. If you or someone close to you needs help, there are services such as the Centros de Integración Juvenil (CIJ), the health center, or your school counselor.
Describe three effects of tobacco on the respiratory and circulatory systems, and explain why quitting smoking improves health even after many years of smoking.
Describe three effects of tobacco on the respiratory and circulatory systems, and explain why quitting smoking improves health even after many years of smoking.
Alcohol is legal for adults and plays a large role in social life. Explain why, despite this, it is particularly dangerous for adolescents, taking into account that…
Alcohol is legal for adults and plays a large role in social life. Explain why, despite this, it is particularly dangerous for adolescents, taking into account that their brain is still developing, and state two specific consequences of its consumption at this age.
An advertising brochure states: "Our vapes only contain water vapor with harmless fruit flavorings; they are the 100% safe substitute for quitting smoking." Critically…
An advertising brochure states: "Our vapes only contain water vapor with harmless fruit flavorings; they are the 100% safe substitute for quitting smoking." Critically analyze this statement based on scientific evidence:
- a) Refute the claim that it is "water vapor": explain what that aerosol actually is and what toxic or addictive substances have been detected in it, detailing how they affect the epithelium of the respiratory tract.
- b) Epidemiological studies indicate that adolescents who vape are up to four times more likely to smoke traditional tobacco two years later than non-vapers. Propose a biological and behavioral hypothesis explaining why vaping acts as a "gateway" to smoking.
At 90 km/h, a car travels 25 m every second. Under sober conditions, the average reaction time of a driver to an unexpected event is 0.8 s. After consuming two beers…
At 90 km/h, a car travels 25 m every second. Under sober conditions, the average reaction time of a driver to an unexpected event is 0.8 s. After consuming two beers (blood alcohol content of 0.4 g/l), their reaction time increases to 1.3 s.
- a) Calculate the distance traveled during the reaction phase in both cases before the driver actually steps on the brake pedal. Interpret the practical consequences of this metric difference when faced with an obstacle at 30 m.
- b) Alcohol is a central nervous system depressant. Justify the apparent contradiction whereby the driver claims to feel "more awake, confident, and with better reflexes" after drinking, relating it to the disinhibition of the prefrontal cortex.
Go back to the beginning: the fact that alcohol and tobacco are sold in any store only tells you about the law; for your developing brain they are still addictive substances with real risks.