You can’t always tell if someone has a mental illness – people might look as though they’re fine and doing well, when actually they’re silently struggling. If someone has bipolar disorder, they may show significant mood swings, or appear more withdrawn if they are dealing with self-harm or negative thoughts, but everything is dependent on the individual and there is no one way to know whether someone is unwell. So, If you get even a single hint of someone being depressed and lost, Try to spend more time with them and make them feel loved and welcomed. Your tiny efforts might actually save their life.