Is there a hormone combination that makes humans grumpy? Imagine a typical situation that is likely to give rise to a bad temper within an individual: a person is awoken very early in the morning by a sound of a lawn being mowed next door. Unlike expected awakening by an alarm clock, such unexpected awakening by a lawn mower is likely to leave the person in a bad temper, feeling grumpy or sulky. **I'm interested if there's a specific hormone or process that makes a person experience the feeling of grumpiness?** Is it related to adrenaline and fight or flight instinct? In other words, can experience of grumpiness be induced under laboratory conditions by using some combination of hormones/drugs?

This is a hard question to respond to.

Many things might make someone grumpy. There are also individual temperaments, making grumpy hard to quantify - a Grumpy to one person might barely be a blip on another individual's scale. Hormones like cortisol reflect stress, and can make people in general irritable, but I doubt any one combination of hormones would always cause grumpiness.

But I thought I'd venture an answer since I did see this paper today: "Low glucose relates to greater aggression in married couples" doi: 10.1073/pnas.1400619111

Being hungry will do this for lots of people, so maybe a bit of an answer for you. There are lots of different kinds of signals that mediate hunger though, so still a tough call.

Update: here's an additional article that specifically talks about parts of the brain involved in aggression and grumpiness as response to a drop in glucose.