Three recent blows to accepted health sciences research offer a critical lesson in institutional fallibility, and long-term correctives in the scientific method.

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Three major reports this month highlight the fragility of ongoing health sciences research, and challenges for broader scientific literacy. Earlier in July, the World Health Organization recommended against the use of non-sugar sweeteners, in a blow to many conventional weight-loss strategies. On July 20, Joanna Moncrieff and Mark Horowitz shared a research review that undermines the “chemical imbalance” approach to depression, and with it an industry’s worth of medical treatment plans. On July 21, Science broke a troubling story of fraudulent Alzheimer’s research that might have set back the discipline by decades.

The WHO’s counsel against non-sugar sweeteners

In a draft guideline open to public consultation until August 14, the WHO advises against using non-sugar sweeteners as a means of “achieving weight control or reducing risk of noncommunicable diseases”. It notes that artificial sweeteners are found in “highly processed foods and beverages” that do not encourage more nutritional eating plans, and which have “possible long-term undesirable effects in the form of increased risk of death and disease”.

Food consultants and industry lobbyists were obviously “disappointed” by this draft guideline, but most affected is the individual attempting to make good, healthy choices in a market economy of competing priorities and recommendations.

Against the “chemical imbalance” theory of depression

In “The serotonin theory of depression: a systematic umbrella review of the evidence”, published in Molecular Psychiatry, Moncrieff et al. outlined the first-ever “umbrella” review of existing research into serotonin’s role in depression. Since the 1990s, the pharmaceutical industry (with the endorsement of the American Psychiatric Association) has promoted the idea of a chemical imbalance “to market a new range of antidepressants, known as selective serotonin-reuptake inhibitors or SSRIs”.

The systematic review found “no consistent evidence of there being an association between serotonin and depression, and no support for the hypothesis that depression is caused by lowered serotonin activity or concentrations”. Medications have been known to numb emotions, but the mechanism of this effect remains unclear. This latest information stands to destabilize patient confidence in existing treatment plans, without culturally supported alternatives for mental health care.

Potentially fraudulent Alzheimer’s research

Alzheimer’s drugs have a 99 percent failure rate in human trials, even as the drugs themselves come with huge price tags that drive up whole markets. Now, researchers know why these drugs have been performing so poorly.

In 2006, Nature shared a paper that suggested that “memory deficits in middle-aged mice” were caused by precursors to amyloid plaques, a build-up in the brain thought to disrupt neural functionality and yield Alzheimer’s. 16 years of pharmaceutical research was developed on this paper’s findings, which forensic image consultants and top Alzheimer’s researchers now agree relied on blatant examples of image tampering: fabricated evidence, in other words.

Daily Kos‘s Mark Sumner noted an added implication of this fabrication: the presence of that amyloid has since been taken as automatic proof of Alzheimer’s. Many other forms of dementia “may have falsely been dragged under the Alzheimer’s umbrella”. The impact of this fraud for medical research and patient outcomes is far-reaching.

Key takeaway

These recent findings represent the fragility of preliminary evidence, and call for a more measured approach to institutional fallibility in relation to scientific progress. But they also gesture at the human cost of any delay in scientific correction. Behind each hard turn in research outcomes lies tens, if not hundreds, of thousands of lives personally affected by preceding missteps. The struggle to do better in our research practices is nothing less than the struggle to prevent further harm from compounding the damage already done by incomplete bodies of knowledge come before.

GLOBAL HUMANIST SHOPTALK M L Clark is a Canadian writer by birth, now based in Medellín, Colombia, who publishes speculative fiction and humanist essays with a focus on imagining a more just world.