Alzheimer's disease is already a serious problem - it is estimated that almost 6 million people in the US alone have the disease. Unfortunately, it is expected to become an even more significant problem, with estimates indicating that the number of sufferers in the USA could reach around 14 million by 2050. This, among other things, is why research is still being conducted into, for example, the early diagnosis of Alzheimer's disease - one of the most recent studies shows that various psychiatric complaints may be the first symptoms of this type of dementia.