Happiness comes in many shapes and sizes. (Matteo Paciotti/Flickr)

Public health discussions about drug and alcohol use tend to be dour, humorless affairs. We talk about all sorts of terrible things associated with drug use, like car crashes and mental illness and kids getting high and people killing themselves and others.

Take a look, for instance, at how the federal government describes the effects of alcohol:

Alcohol affects every organ in the drinker's body and can damage a developing fetus. Intoxication can impair brain function and motor skills; heavy use can increase risk of certain cancers, stroke, and liver disease.

All of this is true, of course, but it's incomplete. You don't pour a glass of wine with dinner to "damage a developing fetus;" you do it because the wine helps you relax after a long day. You don't go out to the bar and down five beers with your buddies to "increase the risk of certain cancers;" you do it because the beer helps the conversation and camaraderie come easier.

In other words, most people get drunk because it's fun.

This is why some new research from Britain is so important: It attempts to quantify exactly how much happiness we derive from that glass of wine or bottle of beer. And it does so using a massive real-time data set — the Mappiness app, a free iPhone app that pings people a few random times a day and asks them how happy they are on a scale of 1 to 100.

The app, developed by the London School of Economics to better understand human well-being, also asks users whom they're with (friends, family, alone, etc.) and what they're doing (working, socializing, drinking, etc.). For the alcohol study, researchers compiled 2 million responses to the app that over 31,000 people recorded between 2010 and 2013. What they ended up with was a large data set that could be used to answer the question: Do people report being happier when they're drinking?

The answer to that question may not surprise you: "drinking alcohol is associated with considerably greater happiness at that moment — 10.79 points on a 0-100 scale," the researchers found. In other words, pour yourself a drink and voilá — an immediate happiness boost.

Of course, drinking alcohol is itself associated with all sorts of other factors known to boost happiness, like hanging out with other people or watching a football game. So when the researchers controlled for all of these things — including what else people were doing, who they were doing it with, where they were and what time of day it was — the alcohol-induced well-being boost dropped down to 4 points. A smaller positive effect, but still highly significant, according to the researchers' models.

Interestingly, they found that the timing and the people with whom you drink had little effect on the overall happiness boost: "There were only relatively small differences in the happiness-inducing effect of alcohol between men and women, or when looking at different times of day, on weekdays vs. weekends, or with different people," the study found.

But the researchers did find that drinking had different effects on happiness depending on what other activities people were doing at the time. "Drinking had the greatest impact when it came alongside otherwise unenjoyable activities (traveling/commuting, waiting), and only increased the happiness of already enjoyable activities by smaller amounts (socializing, making love)." In other words, drinking makes hanging out with friends a little more pleasurable. But it can go a long way toward easing the pain of unpleasant activities, like the morning subway commute — so long as your employer doesn't mind you showing up to work sloshed.

But there's a question of causality hanging above all of this: Does drinking make people happier, or does being happier make people drink? The study was able to control for this, by looking at how happy people reported being earlier in the day. After controlling for prior happiness, the researchers found that the drinking had a slightly smaller boost on overall happiness, but the effect was still significant. That suggests it's more the case that drinking makes you happy, rather than the other way around.

It's also important to note that the sample of app users isn't necessarily a representative one. People download and use the app voluntarily, and the app users tend to be younger and wealthier than the overall population. Still, the sheer size of the data set helps make up for this, and the researchers also controlled for a bunch of standard demographic variables (race, income, gender, etc.) to strengthen their findings.

Finally, the researchers found that the happiness boost from alcohol is a fleeting one. Looking at a different longitudinal survey, they found that, while alcohol consumption was associated with transient happiness, it was not linked to long-term satisfaction. And to the extent that more drinking is associated with more alcohol dependency, it can actually make you worse off in the long-term. So, in short: Don't overdo it.

In the end, the research is a useful confirmation of what most of us know from experience: Drinking is fun. It's a crucial fact that often gets lost in public policy debates about substance use. The harms of excessive drinking are well-known. But if you want to diminish those harms, it helps to understand why people drink in the first place.

More from Wonkblog:

One-fifth of this occupation has a serious drinking problem

Americans are drinking themselves to death at record rates

America's biggest drug threat is 100% legal

Americans like their booze—beer, liquor and (for Washington, D.C., especially) wine. Here's what people in the nation's capital have to say about their own wine-drinking. (Kate M. Tobey, Gillian Brockell and Jhaan Elker/The Washington Post)