There are as many people living with depression as there are citizens of the United States of America. It’s the biggest cause of disability and ill health worldwide, shattering lives and sapping economies, but it is all too often stigmatized or overlooked.

According to the World Health Organization, depression and anxiety cost the global economy $1 trillion as sufferers drop out of the workforce, and every dollar invested in better care would yield a return of $4. Moreover, hard-headed statistics fail to capture the heartbreak of people living with the “black dog”, as Winston Churchill famously termed his own recurrent depression.

World Health Day 2017, on 7 April, aims to raise awareness of depression. Below are some common misconceptions about a surprisingly common illness.

1. Depression is something rare and unusual

It isn’t. Over 300 million people worldwide suffer from depression – 5% of the global population, comparable to the US population of 320 million. Some 10-15% of new mothers suffer post-partum depression.

2. Depression is just a kind of sadness

Sadness is part of the fabric of life, but clinical depression is something else. It can strike without warning or rationale, affecting people who by their own account have nothing to feel sad about. The US National Institute of Mental Health lists symptoms including persistent anxiety, feelings of emptiness or guilt, a loss of interest in the world, difficulty sleeping and eating, as well as restlessness and suicidal thoughts.

3. Depressed people are not high achievers

Try telling that to Winston Churchill, Mohandas Gandhi or Abraham Lincoln, who bore the burden of depression but still left a legacy few healthy people could rival.

There is a lack of clear evidence on how widely mental health problems afflict today’s high-flyers, but a 2015 study in the US found that 30% of entrepreneurs suffered from depression. As one woman diagnosed with moderate depression shared in a blog post:

“Being the co-founder of a company is the hardest thing I’ve ever done to date. My thoughts would be 'You have to be strong', 'You can’t show your weaknesses', 'You have to ride the highs and lows'.

Many start-ups or co-founders especially don’t want to talk about depression because of the fear of being seen as a failure. The cultures of entrepreneurship and business make communicating depression hard.”

4. Depression is a rich-world problem

It’s universal, affecting rich and poor countries alike. What varies around the world is your chance of being diagnosed and treated.

According to the World Health Organization, governments spend on average 3% of their health budgets on mental health, ranging from less than 1% in low-income countries to 5% in high-income countries. Even in rich countries, only half of affected people get treated; in some countries, there are little or no options for help. What’s more, trauma caused by natural disasters, diseases and conflict, far more prevalent in poorer countries, impact depression.

Image: Max Fisher/Washington Post

5. Depression is hopeless

It may be more complicated than healing a broken leg, but there are a range of treatments for depression. The UK’s National Health Service lists approaches which vary according to the severity of the depression, including exercise, cognitive behavioural therapy and medication.