Psychology 101: Intro to Psychology

Have you ever been curious about how psychiatric drugs work, or more specifically, which psychiatric drugs are used for which disorders? This lesson outlines some common psychiatric disorders and how various medications are used to treat and subdue psychotic symptoms.

We usually think of medicine as intended to cure specific physical symptoms; painkillers to help a headache, antibiotics to cure an infection like strep throat. So how can drugs be designed to affect the mind, achieving specific results like making someone less depressed, or getting rid of hallucinations?

Like many medicines, the earliest kinds of psychiatric medications were discovered largely by accident. The first antidepressants were intended as treatments for tuberculosis; the first antipsychotics were developed as anesthetics to use during surgery. These medications were found to improve mental functioning by changing brain chemistry in a variety of ways. In general, they change levels of neurotransmitters in the brain. Neurotransmitters are chemicals in the brain that allow brain cells, called neurons, to communicate with each other. Psychologists have noticed that the amounts of certain neurotransmitters in the brains of people with certain disorders are different than in healthy people's brains, leading to the development of drugs that aim to correct these imbalances.

Antidepressants change the levels of the neurotransmitters norepinephrine and serotonin which affect emotion and mood. There are three basic kinds of antidepressants, called MAOIs (Monoamine Oxidase Inhibitors), tricyclics and SSRI's (Selective Serotonin Reuptake Inhibitors). They all function a little differently. MAOIs and tricyclics raise both norepinephrine AND serotonin levels. SSRIs raise ONLY the levels of serotonin in the brain. This creates fewer side effects than MAOIs or tricyclics, though it does increase sexual side effects like lack of desire and erectile dysfunction. MAOIs have the worst side effects, which is why scientists kept working to make the newer kinds of antidepressants. People who take them must be careful to avoid foods that contain the chemical tyramine. Can you guess what kinds of foods contain tyramine? THE BEST KINDS - beer, some cheeses, cured meats. And if a person messes up and eats these foods anyway, it can produce a fatal interaction with the MAOI. These drugs are usually only recommended to people whose bodies can't tolerate the newer antidepressants.

While antidepressants work primarily on norepinephrine and serotonin, antipsychotics work by reducing the activity of a third neurotransmitter, called dopamine. Dopamine is the neurotransmitter that regulates pleasure-seeking behavior. You know that rush you get when you get an unexpected reward? Maybe you win at the slot machine, or your boss tells you she's decided to give you a bonus? You feel great because your dopamine levels have spiked. But consistently high levels of dopamine can make you really sensitive to excess stimulation, and in the case of schizophrenics this can cause hallucinations and delusions, known as the positive symptoms of schizophrenia. Antipsychotics can help reduce these 'positive' symptoms, called positive NOT because they are 'good,' but because they are things that are 'more' than what most people experience. Most antipsychotics have little effect on the negative symptoms of schizophrenia like blunted emotions and loss of pleasure, but a new generation of drugs called atypical antipsychotics has been shown to have some effect. All antipsychotics can cause side effects like drowsiness, tremors and coordination issues. There is also a very rare, nasty side effect called tardive dyskinesia, which is a permanent neurological condition that causes involuntary movements. This condition persists even after treatment with antipsychotics is stopped.

Bipolar disorder is most commonly treated with another type of psychiatric medication, called lithium. If that sounds familiar from chemistry, you're right; it's an element on the periodic table, and when it's used to treat psychological disorder it's given in the form of a 'salt,' or a kind of chemical compound that includes the element. Though it is an effective mood stabilizer, the way it works in the brain is still unclear. Treatment with lithium also requires careful monitoring, since the active dose is only slightly less than a toxic dose - most medications have a much larger gap between these amounts, making accidental overdoses less common. Lithium has a long history of use as medication; it's believed that the ancient Greeks and Romans used spring water containing lithium to treat manic and depressive disorders. In the early twentieth century, lithium was an ingredient in a beverage still consumed today, then marketed as a hangover cure. There's no lithium in it anymore, but the drink is - have you guessed it yet? - 7UP.

We've gone over three major classes of drugs for three disorders: antidepressants for major depression, antipsychotics for schizophrenia and lithium for bipolar disorders. These all work by altering brain chemistry, though in the case of lithium the exact mechanism is unknown. These drugs can be really helpful to some patients, though psychologists worry about prescribing them without careful consideration or as a substitute for talk therapy. Since many of the drugs do not keep working after a patient stops treatment, many patients take them for a very long time and such long-term side effects aren't always known. Given these problems, psychiatric medication should be seen as simply one type of therapy, likely to be used alongside other types, and not a be-all-and-end-all treatment for psychological disorders.