A systematic sift through the United Kingdom's Biobank has revealed several habits and behaviours that can exacerbate depression.

Similar to physical activity - a known mood booster - the authors of the new study highlight potential targets that could help to reduce depression risks, such as regular socialising.

"Far and away the most prominent of these factors was frequency of confiding in others, but also visits with family and friends, all of which highlighted the important protective effect of social connection and social cohesion," says psychiatrist Jordan Smoller at Harvard Medical School.

"These factors are more relevant now than ever at a time of social distancing and separation from friends and family."

As many around the world are still living in lockdown due to the relentless COVID-19 pandemic, social visits and hanging out with family is - understandably - more difficult than ever. However, the new findings are a gentle reminder that hiding away in front of the TV can exacerbate an already low mood, and making the effort even just to call a friend could offer a benefit.

What factors are tied to depression, what factors lead to depression, and what factors are caused by depression are hard to tease apart, but using large cohorts, statistical tools, and randomisation frameworks, researchers are starting to get a better idea of their potential outcomes.

When studied alone, some factors, like diet, appear to have a big impact on depression, but the key here is relativity.

Scanning patient data for more than 100 potential risk factors, the authors of this new study have created a comprehensive comparison of factors like never before.

Using Mendelian randomisation - a method traditionally used for calculating genetic risk - they have identified a number of social, lifestyle and environmental factors that might influence our mood and are worth considering further.

"Depression is the leading cause of disability worldwide, but until now researchers have focused on only a handful of risk and protective factors, often in just one or two domains," says psychiatrist Karmel Choi, also from Harvard University.

Combing through data on 100,000 white Brits, the authors found spending more time in front of the television was linked to a greater risk for depression at the appointment follow-up. On the other hand, regular social activities had a protective effect.

Placing your trust in friends and family, for instance, was particularly powerful at lowering a person's risk for depression.

The authors have previously shown the same thing with physical activity. People who are depressed, it appears, are not simply exercising less. Instead, the findings suggested that those who exercise more are less likely to be depressed, possibly because they are getting up and moving.

Now, using the same framework for causation, the team has found another potential protective mechanism: our friends and family.

While confiding in others provided the most protection against depression, even amongst at-risk individuals, the authors also say visiting with family and friends was "nominally significant".

Altogether, this suggests frequent socialising with loved ones might protect us against future bouts of depression, while spending considerable amounts of time watching television can do the exact opposite.

The authors aren't sure why this is the case, but it could be that the media we are consuming have some impact on our mood. Alternatively, it could also have something to do with spending several passive hours on our backsides.

Teasing apart the various nuances of our behaviour and our moods is exceedingly difficult, and perhaps we are simplifying things too much.

While overall sleep duration and quality is related to depression, the current study found daytime naps might increase the risk of depression. This suggests there are probably complex and nonlinear effects we aren't taking into account, and additional studies should dig further into these possibilities.

Daytime sleepiness, for instance, may very well be caused by depression and vice versa, creating a potentially nasty feedback loop that creates a chicken-and-the-egg conundrum for researchers.

For now, it seems like socialising with friends and family, and physical activity are two promising ways to protect your mental health.

That said, current social distancing measures can make it hard for many of us to take full advantage of the advice that states we need more family time and less Netflix to help avoid depressive moods - even when we know hitting that button to watch the next episode is not the best remedy.

"Regardless," the authors write, "our findings suggest that health care provider assessment of media use patterns in adult patients and providing psychoeducation on the potential mood impacts of excess television watching could represent another effective component of depression prevention."

The study was published in the American Journal of Psychiatry.

If this story has raised concerns or you need to talk to someone, here's a list where you may be able to find a crisis hotline in your country.