Why is it that depression is so random and hard to detect, that even the happiest person turns out to be the worst mentally?

People can put up a front because they are scared of letting others in. They build walls to protect themselves from the opinions of others, or from people that they do not want to open up to. Society pressures us all to be happy and positive 24/7 so when we are feeling down, we tend to want to immediately not accept our feelings and cover them up by "acting" like we are fine. Asking for help can also be too much for some people. At the end of the day, we all deal with very individual emotions and personal thoughts. What seems like a perfect life to one person can actually be a living hell to another. We all deal with situations and struggles differently, and we react to hard times differently. What seems like an easy life to one can be really, really challenging for another. It is so hard to tell how someone really feels nowadays, but just let them know that you are not going to judge them and that you are always there to listen when they need to talk. That is the best you can do sometimes!

Because of the nature of depression, people that suffer from it can have tremendous difficulty in expressing how they are feeling. They can become very very expert at appearing fine, just so that they won't have to say how they really are feeling. So the "happiest person" isn't actually that happy, necessarily. They may be desperately sad inside. How can you know this ? By asking people questions, and not judging their answers, and by not being scared by negative things. Negative things exist, but ignoring them doesn't make them go away. By accepting them and working through them their effects can be significantly reduced.

This is because people hide their troubles with the thought that they don't want to burden/bother their loved ones with more issues. That's why they smile through the pain, because they'd rather be the ones suffering in quietude than to see their love ones in pain. People in depression are really kind :(

In many ways, depression is a loss of happy feelings. Your present life may be calm and free of trauma, but for some a sense of unfulfilment and isolation gradually builds up. And even when 'happy events' take place, you can't seem to enjoy them as you wish. Regardless, I think it's important not to associate depression with the person's lifestyle. It's an illness with potential fatal consequences, and as Alastair Campbell says: 'You would never say: “What does he have to be cancerous about, diabetic about, asthmatic about?” (...) Nobody ever gets blamed for getting physical illness – even when those illnesses do result from lifestyle choices – so why on earth do we still talk about depression like it is the fault, and the lifestyle choice, of the depressive?'

I would disagree that depression is "random," or "hard to detect." More often than not, warning signs are present-- we simply (1) don't know what to look for, or even (2) ignore them, perhaps even explain them away.

I think it's hard to tell who has it and who doesn't because people with depression tend to try harder to make sure that everyone around them is as happy as possible. We know how it feels to be sad, and we don't want anyone else to go through it, so we put aside our sadness so we don't bum anyone else out. The other thing is that it's a mental illness. It's not something that you can see directly, making it really easy to not notice if you don't know the signs or the person is very good at hiding their symptoms.

Depression is hard to detect because many depressed people hide their depression and pretend to be happy.

This could be due to any number of reasons! It could be a hormonal shift due to any number of environmental factors, it could be something that we're subconsciously worried about, or it could just be time for you to eat, have some water, or relax! You should visit the doctor to find out the true cause of your specific case.

It's not always this way, but people do tend to be quite far in before they actually have a problem with it. It's not abnormal to feel really depressed without a huge life event occurring.

because they don't want you to know it at all. so stop pestering yourself on how you detect something people don't want you to detect start to realize that someday they will tell you that they are depressed