It is sometimes confused with persistent depressive disorder (PPD), which is a mild to moderate chronic depression, according to the Cleveland Clinic. 

Meltzer said a common sign of high-functioning depression is 'wearing a mask' to hide your internal mental health struggles.  

'You take care of important things, work, school, bills. On the outside, everything seems normal, but on the inside, you're feeling empty and numb,' he explained. 

Another sign that the therapist pointed out is 'endless exhaustion,' which is a common symptom of depression in general. 

'No matter how hard you try, you're always running on low energy,' he said. 'It feels like an endless struggle and it can be utterly exhausting. This can cause you to feel helpless, like you will never find energy again.'

Meltzer noted that if you are struggling with high-functioning depression, you may be drawn to 'numbing habits,' including mindlessly scrolling through social media, eating junk food, and playing video games for hours. 

'These behaviors might be your way of numbing your feelings of emptiness,' he said.

The therapist explained that this may coincide with a loss of pleasure in the activities that used to bring you joy.

'It's like the color has faded from the things that used to light you up,' he said. 

Meltzer advised that you should also watch out for any instances in which 'small irritations become major triggers.' 

'Negative events start to reinforce the belief that you're not enough,' he said. 'It's a slippery slope, for even the smallest setbacks can feel extremely overwhelming.'

The expert added that another sign of high-functioning depression is 'persistent self-criticism.' 

'You're becoming your own worst critic, and you find it hard to give yourself a break,' he said. 'Every mistake feels like a personal failure.'

Finally, Meltzer explained that 'isolating yourself from your friends and family' can also be a sign of high-functioning depression.

The therapist's video has been viewed 7.9 million times and has received more than 5,000 comments since it was posted a few months ago. 

Many commenters shared that they had most or all of the symptoms. 

'Does it go away at some point?' one person asked. 'Not sure how long I can keep the "high functioning" part up....'

'[Number six] is how my [doctor] diagnosed me,' another added. 'I never considered myself depressed but was endlessly exhausted. [Antidepressant] Wellbutrin changed my life.'

Others couldn't help but joke about how they had all seven signs of high-functioning depression. 

'Woo I haven't gotten 100% on a test in a long while,' one user responded. 

'This is the first test I ever passed! Oh...,' someone else commented.