Mental health issues are still somewhat stigmatised in society, and a majority of sufferers don't seek treatment. But why the stigma? The problem with mental health issues as opposed to physical disabilities is that they are often 'invisible', i.e. not obvious to an observer. It may be a lot easier to feel sympathetic towards somebody in a wheelchair than someone with such chronic depression that they find it near impossible to get out of bed, if only because you have visual evidence of difficulty in the former case.
Unfortunately, this problem can be exacerbated when sufferers find coping methods. If a person in a wheelchair has found ways to get on with life as normally as possible, they may continue to attract sympathy and understanding because people can still see the chair. But if a person with mental health issues has found ways to disguise their inner suffering, it's difficult for an observer to realise that they have a problem, or believe it if they're told.
One example of an 'invisible' mental health disorder is Asperger's Syndrome, or AS. AS is much like autism, with symptoms such as difficulties in social interaction (particularly nonverbal communication and empathy) and repetitive behaviours and interests. But it differs enough from autism that it's harder to spot. For example, people with AS have relatively normal linguistic and cognitive development. So to an observer, AS is far less obvious than autism. And again, this becomes more of an issue when a person with AS has found ways to cope.
Asperger's Syndrome is managed with behavioural therapy. The patient learns how to limit their repetitive behaviour, and appropriate ways to act in particular social situations. But if behaviour is changed, then the very symptoms that led to their diagnosis are diminishing. Which might sound like a good thing, until the person with AS encounters observers who subsequently don't believe they have a problem. A child with AS who has been taught well how to cope with situations that regularly occur in everyday life might still need extra time in exams, but be refused by a teacher who doesn't understand enough about the disorder to realise that someone outwardly coping might still inwardly suffer. It may be a relief for a person with AS if their peers don't treat them like somebody with a mental health disorder, until a time comes when they do struggle, and their explanation as to why is either not understood or not believed, because of a lack of awareness. The sufferer may even feel like a fraud.
Sufferers might take comfort in knowing that if friends and family find it difficult to believe they have a mental health disorder, it is probably just because they care about the person enough not to want them to have a problem of any kind. But the only person who can tell you for sure if you have a mental health disorder is a qualified professional. If you think you might have Asperger’s Syndrome - because, for example, you struggle with picking up on facial expressions and body language - then you should visit a doctor, who can recommend you to a diagnostician. And if you do have a diagnosis, don’t let anyone who isn’t trained to do so tell you that they don’t believe it. Instead, try to help them understand a little better. With more education, we can start to get rid of the stigmatism that surrounds these issues to do with mental health.