Part of the problem is bias however, this can be done in an obvious or an unintentional way by friends, family, even the medical doctor. Sometimes, because the diagnosis and treatment of mental illness is difficult and doesn't present as easily as finding a heart problem for instance, it may take awhile to get the correct treatment. After the 1950's some scientists stated that mental disorders were caused by nervous system or brain problems and should be treated like other physical illnesses. It is thought that more than half of people in the U.S. with a mental condition are receiving no help and this may due to persistant stigmas associated with these conditions. People may fear for the safety of their job, being rejected by others, etc. as to why they may not get the treatment they need. Their health insurance plans may not adequately cover the therapy they need, for the specific length of time they might need it. Treatments include pyschiatric medications, psychosurgery, psychotherapy, shock therapy.
People tend to fear what they don't understand. Dispite all the advances in the diagnosis and treatment of people with mental illnesses, most people still don't understand them (the illnesses or the people with them) and therefore, at least on a subconscious level, fear them. This makes people who suffer from mental illnesses very reluctant to come forward. Therefore, many people suffer in silence.
in today's world too many people link or even tag, mentally challenged people as maniac or crazy. as a result many people think that such 'mad' people may harm them, they thus tend to avoid them. resulting in lack of care and supervision.