What does depression look like? It can look like anyone and everyone — and that's the vital message of the hashtag #MyDepressionLooksLike, which took Twitter by storm over the weekend.

#MyDepressionLooksLike made the case that depression can manifest itself in a wide variety of ways among different people. Perhaps most important, it conveyed that depression may look like nothing at all to those on the outside. As therapist Jessica Bernal told ATTN:

"[There] are people all over, every day, that are super high-functioning — that have an education, jobs, partners —and have mental health issues. I don't use the word 'normal,' but I use the word 'normalizing.' [Education teaches people that] what it looks like is not what [they] thought it would look like."

Individuals used the hashtag to show that people who smile or seem outwardly OK may still suffer silently with depressive episodes.

The tweets reveal a truth long acknowledged by mental health professionals: A person needn't look sad or be incapable of functioning day to day to be depressed.

Depressed people are often depicted as crying all the time or being unable to get out of bed to face the world. But this isn't true for all people suffering with depression. Mental health professionals refer to "smiling depression," and the tweets shed light on the way that depression can wear a mask. Psychologist Rita Labeaune described it like this:

"People suffering from smiling depression may offer no hint of their problem to the outside world. They often maintain a full-time job, run a family household, participate in sports, and have a fairly active social life. With their mask on, everything looks great, even at times perfect. However, underneath the mask they are suffering from sadness, panic attacks, low self-esteem, insomnia, and, in some cases, suicidal thoughts."

The hashtag reveals that the symptoms of depression differ from one person to another.

Depression can be about sadness, but the hashtag shows that it can be about much more. The tweets reveal that people with depression may feel worthless or simply drained and tired all the time. They show the reality of depression to those who have not experienced it — and may also help break down the stigma that prevents people from talking about depression.

"I think that you always have to ask the person their experience and what they want," said Rabbi Rachel Bat-Or, a marriage and family therapist, in an interview with ATTN:.

Depression is one of the most common mental health issues in the United States, affecting almost 7 percent of the adult population in a given year, according to the National Institute of Mental Health.

Globally, more than 350 million people suffer from depression; in the United States, one in five adults will experience some form of mental health challenge annually. Given how universal such challenges are, it's time that we all learn to be better mental health allies, for ourselves and for others.

If you or someone you know is experiencing depression, particularly suicidal thoughts, you can reach out to the National Suicide Prevention Lifeline at 1-800-273-8255. You can also find more resources to help you or a loved one deal with depression through the National Alliance on Mental Health.

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