"An important finding highlighted in this study is that studies done by the World Health Organization (WHO) have found that "developing countries (non-Western) experience far higher rates of recovery from schizophrenia than Western countries". The researchers further articulate that these findings may be due to culturally specific meaning created about the experience of schizophrenia, psychosis, and hearing voices as well as "positive expectations around recovery". Research has found that auditory hallucinations and hallucinations more broadly are not necessarily a symptom of "severe mental health" and instead might be more commonplace than assumed and also experienced by people in the general population. According to a literature review, "The prevalence of voice-hearers in the general population: A literature review", which compared 17 studies on auditory hallucinations in participants from nine countries, found that "differences in the prevalence of [voice-hearing in the adult general population] can be attributed to true variations based on gender, ethnicity and environmental context". The studies took place from 1894 to 2007 and the nine countries in which the studies took place were the United Kingdom, Philippines, United States, Sweden, France, Germany, Italy, Netherlands, and New Zealand. The same literature review highlighted that "studies that [analyzed] their data by gender report[ed] a higher frequency of women reporting hallucinatory experiences of some kind". Although generally speaking hallucinations (including auditory) are strongly related to psychotic diagnoses and schizophrenia, the presence of hallucinations does not exclusively mean that someone has a psychotic or schizophrenic episode or diagnosis.
He writes that the condition is called "Denti di Chiaie" (Chiaie teeth), named after Stefano Chiaie, an Italian professor. In the United States of America, a dentist, Frederick McKay, set up practice in Colorado Springs in 1901 and discovered a high proportion of the residents had stained teeth, locally termed the "Colorado brown stain". He took this information to Greene Vardiman Black, a prominent American dentist of the time. After examining specimens of affected enamel, in 1916 Black described the condition as "[a]n endemic imperfection of the enamel of the teeth, heretofore unknown in the literature of dentistry." They made the interesting observation that although the mottled enamel was hypomineralized, and therefore should be more susceptible to decay, this was not the case. Gradually, they became aware of existing and further reports of a similar condition worldwide.In 1931, 3 different groups of scientists around the world published their discoveries that this condition was caused by fluoride in drinking water during childhood. The condition then started to become termed "dental fluorosis". Through epidemiological studies in the US, Henry Trendley Dean helped to identify a causal link between high concentrations of fluoride in the drinking water and mottled enamel. He also produced a classification system for dental fluorosis that is still used in modern times, Deans Index. As research continued, the protective effect of fluoride against dental decay was demonstrated. References


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