Will soldiers of the future be given serotonin depressors to make them depressed and therefore fearless? A new study released Friday shows that people with a low level of serotonin do not "reflexively avoid" bad situations, and are more likely to explore risky and dangerous places. This is a sorry state in everyday life, but might be desirable if you're a soldier and need to venture into spots most people would steer clear of. It's very possible the next "super soldier" drug won't give you superstrength, but just a megadose of depression.
For people who aren't in the soldiering life, the study offers a different insight: Being depressed makes you likely to seek out situations that will depress you more. Because you've become less risk-averse, you're more likely to go down a dark alley that people with higher levels of serotonin would avoid. And if you got beaten up in that dark alley, the resulting compounded depression might make you do something even riskier next time.
Taking a serotonin reuptake inhibitor like Prozac, which keeps more serotonin circulating in your brain, actually causes you to avoid bad situations as well as evening out your mood.
Seratonin, Inhibition, and Negative Mood [PLoS Computational Biology]