This 2015 Harvard rodent study found multiple undesirable symptoms and attributed the cause to insulin resistance, which is itself a symptom.

Humans most often develop the symptom of insulin resistance due to causes other than genetics, such as a result of abnormal eating behaviors, which are symptoms of other causes.

Use of insulin-resistant-due-to-genetics mice may have misdirected the researchers to lose focus that their ultimate task was to find ways that their research can help humans. If helping humans was the researchers’ focus, it may have occurred to them to develop evidence for how “something” caused symptoms such as abnormal eating behaviors, that in turn caused a symptom of insulin resistance.

The study’s unexamined causes included why genetically insulin-resistant mice developed symptoms of anxiety and depressive-like behaviors between early adulthood and late middle age. Examples of undesirable symptoms described in the supplementary material included:

• Higher body weight in late middle age, especially in females;
• Depressive-like behavior in both sexes by late middle age;
• Higher corticosterone levels in both sexes by late middle age, even when unstressed; and
• Higher corticosterone levels in late middle age when stressed, especially in males.

It’s remarkable how researchers consistently get caught in a loop of studying only symptoms, paying little attention to studying causes, then suggesting various medications and treatments to suppress the studied symptoms.

It’s not surprising then that there’s no explanation of why and how symptoms develop. The study designs seldom include trying to show causes for the effects in the first place!

http://www.pnas.org/content/112/11/3463.full “Insulin resistance in brain alters dopamine turnover and causes behavioral disorders”