There are certain warning signs that are easy to decipher when diagnosing a person with depression. But others are much more subtle and can be overlooked. In fact a close person in your life may be struggling with severe mental health issues, yet present themselves in a happy or positive way. We feel it is important to bring topics like “smiling depression” to the forefront because it is these cases that can leave people unprepared for severe consequences (such as a surprise suicide, perhaps).

The Fix recently covered this topic on their blog page, highlighting just how common it is for a depressed person to put on the facade of happiness. In fact, their research shows that up to 40 percent of people who suffer from depression may not exhibit outward symptoms (such as crying, sadness and the inability to get out of bed).

“It can be very hard to spot people suffering from smiling depression,” Science Alert researcher Olivia Remes told the site. “They may seem like they don’t have a reason to be sad—they have a job, an apartment and maybe even children or a partner. They smile when you greet them and can carry pleasant conversations. In short, they put on a mask to the outside world while leading seemingly normal and active lives.”

Remes went on to say that there can be other visible symptoms of smiling depression beyond outward unhappiness. Call outs included sudden weight gain, a change in appetite, constant sleepiness and increased withdrawals from social events. So people suffering from this could be quite jovial when they see you, but still change certain behavioral patterns.

University of Michigan professor Dr.Michelle B. Riba was also quoted on the site. She actually felt that people who fall under the smiling depression category may not even realize that they themselves have a problem.

“Many people will come to their doctor complaining about sleep problems, or headaches, not realizing that it’s a mood disorder because they don’t have low mood,” she explained. “Not all symptoms of depression always occur at once.”

Eventually though, the dark feelings do catch up to you and that’s where a condition like this could really get serious. How many times have we heard about seemingly “happy” people taking their own lives? If you ask us, it is always important to check in with those close to you and lend support if you suspect that smiling depression may be lurking underneath an upbeat smile.