Thankfully, a nervous breakdown is typically a short-lived thing. Medical or therapeutic intervention usually sees people return to normal eventually, or just the enforced break from stress may help. Granted, not everyone sees a nervous breakdown as a helpful thing; not everyone gets over it, and those who do often retain a sensitivity to stress and adversity that means they could more easily experience a nervous breakdown again.16 But they can at least resume a normal life, or a close approximation of it. Hence nervous breakdowns can help prevent lasting damage from a relentlessly stress-filled world.
Saying that, many of the problems a nervous breakdown helps limit are themselves caused by the brain’s own techniques for dealing with stress, which often aren’t up to scratch for modern life. Appreciating the brain for limiting the damage caused by stress via nervous breakdowns is like thanking someone for helping put out the fire in your house when they were the one who left the fryer on.
Dealing with the monkey on your back
(How the brain brings about drug addiction)
In 1987, there was a televised public-service announcement that illustrated the dangers of drugs via the use of, surprisingly, eggs. An egg was shown and the viewer was told, “This is your brain.” A frying pan was then shown, with the sentence, “This is drugs.” The egg was then fried in the pan, with the words, “This is your brain on drugs.” In a publicity sense, it was very successful. It won awards, and is still referenced (and, admittedly, mocked) in pop culture to this day. In a neuroscientific sense, it was a terrible campaign.
Drugs do not heat your brain so much that the very proteins making up its structure break down. Also, it’s very rare for a drug to affect every part of the brain simultaneously, in the way that a frying pan affects an egg. Lastly, you apply drugs to the brain without removing it from its shell, aka skull. If you did, drug use certainly wouldn’t be so popular.
This isn’t to say drugs are necessarily good for the brain; it’s just the truth is far more complicated than egg-based metaphors can allow for.
The illegal drug trade is estimated at nearly half a trillion dollars17 and many governments spend countless millions finding, destroying, and discouraging the use of illegal drugs. Drugs are widely assumed to be dangerous; they corrupt users, damage health and ruin lives. This is fair because drugs often do exactly that. Because they work. They work very well, and do so by altering and/or manipulating the fundamental processes of our brains. This causes problems such as addiction, dependence, behavioral changes and more, all of which stem from how our brains deal with drugs.
In Chapter 3, the dopaminergic mesolimbic pathway was mentioned. It’s often called the “reward” pathway or similar, because its function is refreshingly clear: it rewards us for actions perceived as being positive, by causing the sensation of pleasure. If we ever experience something enjoyable, from a particularly pleasant satsuma to the climax of a certain bedroom-based activity, the reward pathway provides the sensations that make us think, “Well, wasn’t that pleasant?”
The reward pathway can be activated by things we consume. Nutrition, hydration, alleviating appetite, providing energy; edible substances that do these things are recognized as pleasant because their beneficial actions trigger the reward pathway. For example, sugars provide easily utilized energy for our bodies, so sweet-tasting things are perceived as pleasant. The current state of the individual also plays a part: a glass of water and slice of bread would usually be considered the most uninspiring meal, but would be divine ambrosia to someone just washed up after months adrift at sea.
Most of these things activate the reward pathway “indirectly,” by causing a reaction in the body that the brain recognizes as a good thing, thus warranting a rewarding sensation. Where drugs have the advantage, and what makes them dangerous, is they can activate the reward pathway “directly.” The whole tedious process of “having some positive effect on the body that the brain recognizes” is skipped, like a bank employee handing over bags of cash without needing boring details like “account numbers” or “ID.” How does this happen?
Chapter 2 discussed how neurons communicate with each other via specific neurotransmitters, including noradrenaline, acetylcholine, dopamine, serotonin. Their job is to pass signals between neurons in a circuit or network. Neurons squirt them into synapses (the dedicated “gap” between neurons where communication between them occurs). There they interact with dedicated receptors like a specific key opening a specific lock. The nature and type of receptor the transmitter interacts with determines the activity that results. It could be an excitatory neuron, which activate other regions of the brain like someone flicking a light switch, or it could be an inhibitory neuron, which reduces or shuts down activity in associated areas.
But suppose those receptors weren’t as “faithful” to specific neurotransmitters as hoped. What if other chemicals could mimic neurotransmitters, activating specific receptors in their absence? If this were possible, we could feasibly use these chemicals to manipulate the activity of our brains artificially. Turns out, it is possible, and we do it regularly.
Countless medications are chemicals that interact with certain cell receptors. Agonists cause receptors to activate and induce activity; for example, medications for slow or irregular heartbeats often involve substances that mimic adrenalin, which regulates cardiac activity. Antagonists occupy receptors but don’t induce any activity, “blocking” them and preventing genuine neurotransmitters from activating them, like a suitcase wedged in an elevator door. Antipsychotic medications typically work by blocking certain dopamine receptors, as abnormal dopamine activity is linked to psychotic symptoms.
What if chemicals could “artificially” induce activity in the reward pathway, without us having to do anything? They’d probably be very popular. So popular, in fact, that people would go to extreme lengths to get them. This is exactly what most drugs of abuse do.
Given the incredible diversity of beneficial things that we can do, the reward pathway has an incredibly wide variety of connections and receptors, meaning it’s susceptible to a similarly wide variety of substances. Cocaine, heroin, nicotine, amphetamines, even alcohol—these all increase activity in the reward pathway, inducing unwarranted but undeniable pleasure. The reward pathway itself uses dopamine for all its functions and processes. As a result, numerous studies have shown that drugs of abuse invariably produce an increase in dopamine transmission in the reward pathway. This is what makes them “enjoyable”—particularly drugs that mimic dopamine (cocaine, for example).18