As previously reported in the series, the World Health Organization has made some dire predictions about mental disorders: 115.4 million people will have some form of dementia by 2050, though a large portion of those cases will remain undiagnosed. The majority of the increases of dementia will be in lower- and middle-income countries. The results may be devastating – but not for the reasons that you think.

The proportion was thought to be higher in high-income countries, in part because of the cultural limitations presented in diagnostic efforts such as those used by the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders. But the 10/66 study, a two- to three-hour survey carried out in people's homes which tests cognitive ability, problem solving, and mental state examination, has shown that the prevalence is much higher than previously suspected. As Martin Prince, professor of Epidemiological Psychiatry at the Institute of Psychiatry in King's College London, Co-Director of the KHP/ LSHTM Centre for Global Mental Health, and coordinator of the 10/66 Dementia Research Group, explained, mental state is examined because "depression and alcohol abuse can be confused for dementia."

Current research, particularly by the 10/66 Dementia Research Group, pegs 60 percent of people affected with dementia as living in low- and middle-income countries. That number may seem concerning – and in many ways, it is. Dementia is poorly understood, in many high-income countries but particularly in low- and middle-income ones.

Bébène Bandzouzi, from Brazzaville's University and Hospital Center (CHU), as well as Maëlenn Guerchet and Pierre-Marie Preux from the National Institute of Health and Medical Research (INSERM), and their team, have studied incidences of dementia in many sub-Saharan African countries. They said an email that "dementia is perhaps perceived as a punishment to be paid for a fault committed by a person, or by the person's parents." In some cultures, Prince says that one explanation for dementia is witchcraft. In many languages, there is no word for dementia – just madness. (English has only come so far; its roots come from the Latin "derangement of the mind.")

In most lower- and middle-income countries, there is no welfare system, causing most dementia sufferers to be reliant on family members for care. Prince describes the coordination of care in many countries to be rather happenstance, foisted on one caretaker. The caretaker, usually a woman, is often put in the difficult situation of caring for two generations at the same time: her own children, and the elderly sufferer of dementia. As a result, the family often loses two sources of income – that of the person with dementia, and that of the caretaker.

But interestingly, while some caretakers do feel vague irritation and agony about caring for sufferers of dementia, many feel a sense of pride about taking care of an elderly relative. In the WHO's report, there are quotes from caretakers in India. One 28-year-old married man said, "Sometimes he forgets our name;, that is what is difficult. Otherwise there is no problem in looking after him. That at such an age he should have this problem is painful for us. Everybody understands his problem. Family and friends are very helpful. They come over frequently and give us advice as to what we should do. Right now there isn’t much work for us. My wife and I manage to look after him. He has looked after us, his children, so well for all these years. It gives me pleasure to look after him. God has given me an opportunity to serve him."

Indeed, Bandzouzi, Guerchet, and Preux added that, in the Brazzaville neighborhoods they visited were "a matriarchal society, where the mother was the center of the family. Dementia [is] in general well-tolerated because people take care of their 'mamans.'"

But in fact, it is well-tolerated up to a point. While Bandzouzi, Guerchet, and Preux describe deep respect for the elderly, some of the symptoms of dementia are able to be put up with more easily than others. They say, "When the behavioral troubles become evident in subjects with dementia, they can become socially intolerable: for example, a grandfather coming into his granddaughter's room at night. Because of his problems with orientation, he does not remember that he's not in the right house, and is immediately stigmatized and accused of wrongdoings (principally sorcery). Even the family will not accept that, and will act to exclude the grandfather from the home or reprimand him violently." Caretakers describe a great deal of stigma, retreating ever more often into their homes. When elderly relatives appear in public showing a great deal of disarray, Prince says that families are often blamed, charged with "neglecting the older person, even harming them."

Governments have long buried their heads in the sand on the matter – and in many of these countries, for a long time, they have had that ability to ignore the problem but now, as populations age, many low- and middle-income countries are in a state of transition. Elderly relatives' young children have moved away to other parts of the country for schooling and for work. Researchers report that these transitions have caused the younger generation to view the act of caring for elderly relatives afflicted with dementia more negatively than previous generations.

The transitional state of countries, in which they become more industrialized, has deep ramifications for families and for cultures. But they may also have ramifications for preventative networks against dementia as well. It has been widely accepted that cognitive exercises can decrease the risk of getting dementia, and many of the elderly residents catalogued by Bandzouzi, Guerchet, and Preux are illiterate with very low levels of schooling. The researchers readily concede that illiteracy has been accepted as having a role in the development of dementia.

"Meanwhile," they write, "the situation may be more complex on the African continent. Certain countries have conserved a cultural oral tradition, which is very present in the education of children and in everyday life (apprenticeships in rural areas, etc). This oral tradition may have a 'protective' effect against illiteracy and lack of schooling."

Thus, while sub-Saharan Africa forges ahead with the rest of the world in becoming more industrialized, members of various cultures are scattered around their countries and the continent. Their youngest members become more educated, which is of course a good thing, but as a result, will probably have less access to the oral tradition of their ancestors, and will be less able to take care of their parents and grandparents. And perhaps, they will have less access to the preventative benefits of those oral traditions that their parents had.