This is one of the studies that Big Pharma will probably spend a lot of money on trying to get retracted. It directly demonstrates that elevated serotonin (5-HT) in the brain drives brain atrophy and depression. Both the rates and severity of these conditions increase with aging and the study demonstrates that, coincidentally, the brain’s capacity to synthesize 5-HT also increases with age. So, all those SSRI drugs being handed out like candy to even toddlers, are doing nothing but replicating this pathological 5-HT excess in all age groups. It is little wonder the IQ scores have been dropping since the 1990s and show no sign of reversing or even flattening the downward trend. Another, just as important, corollary of the study is that systemic corticol and estrogen are also likely rising with age, in direct contradiction to what we are being told by mainstream medicine, especially in regards to women. The reason is that 5-HT is one of the most potent inducers of ACTH release (likely even stronger than CRH) as well as the aromatase enzyme. Conversely, serotonin antagonists have been successfully used to treat diseases of excess cortisol (e.g. Cushing’s, obesity, diabetes, etc) as well as excess estrogen (gyno, breast cancer, infertility, etc). So, with just one drug class (SSRI) Big Pharma is directly contributing to some of the most frequent chronic conditions, both mental and physiological (actually, they are one and the same).
https://www.nature.com/articles/s41380-023-02177-x
“…The dorsal raphe nucleus (DRN) is one of the earliest targets of Alzheimer’s disease-related tau pathology and is a major source of brain serotonin. We used [18F]Fluoro-m-tyrosine ([18F]FMT) PET imaging to measure serotonin synthesis capacity in the DRN in 111 healthy adults (18–85 years-old). Similar to reports in catecholamine systems, we found elevated serotonin synthesis capacity in older adults relative to young. To establish the structural and functional context within which serotonin synthesis capacity is elevated in aging, we examined relationships among DRN [18F]FMT net tracer influx (Ki) and longitudinal changes in cortical thickness using magnetic resonance imaging, longitudinal changes in self-reported depression symptoms, and AD-related tau and β-amyloid (Aβ) pathology using cross-sectional [18F]Flortaucipir and [11C]Pittsburgh compound-B PET respectively. Together, our findings point to elevated DRN [18F]FMT Ki as a marker of poorer aging trajectories. Older adults with highest serotonin synthesis capacity showed greatest temporal lobe cortical atrophy. Cortical atrophy was associated with increasing depression symptoms over time, and these effects appeared to be strongest in individuals with highest serotonin synthesis capacity. We did not find direct relationships between serotonin synthesis capacity and AD-related pathology. Exploratory analyses revealed nuanced effects of sex within the older adult group. Older adult females showed the highest DRN synthesis capacity and exhibited the strongest relationships between entorhinal cortex tau pathology and increasing depression symptoms. Together these findings reveal PET measurement of the serotonin system to be a promising marker of aging trajectories relevant to both AD and affective changes in older age.”
