Human Skulls Mounted on Stakes Found at 8,000-Year-Old Burial Site in Sweden

Whether today we consider ancient practices abhorrent or not is a different matter though. In general those can be explained by cultural differences, and there is no need to invoke mental health. Improvements in psychological well being isn’t universally correlated with increased pacifism, as some people here seem to think. Modern western civilization is a product of very specific historical events - not a progression toward our "evolutionary ingrained instincts". If anything, judging by the vast majority of human history - our "evolutionary ingrained instincts" are far more tuned toward violence than what is considered acceptable today in the western world.

A mentally healthy individual in modern US would act very differently from a mentally healthy individual in ancient Rome.

Also your argument that human biology and psychology override social norms is unfounded. That is context-dependent, and cultural norms are the case specifically to influence biology and psychology! For example, what we eat and how we eat is directly related to cultural norms, and what we eat directly influences our biology. Over the course of time, our bodies compensate and adapt to our eating patterns as a society, influencing both prevalence and development of disease, as well as how we respond psychologically to cultural changes in diet. The dynamic between culture, psychology, and biology is extremely complex, and it cannot be definitively stated that the body wins over the mind, in any case.

edit: a more specific example of the kind of dynamic I'm referring to would be restrictive eating disorders. Eating is both a psychological and biological response. We eat because we nourish our bodies, our bodies let us know when we need to eat by sending signals to our brain, which we interpret as a kind of discomfort or pain. The pain, psychologically, distresses us even apart from the physical sensation. However, due to cultural developments in the way we view bodies, many people completely override their biological pain response in order to achieve what they perceive to be a cultural norm. You may say this proves your deducted result, but I would argue that in many ways the cultural norm can be perceived to encourage eating disorders. Yet, somehow, those with restrictive eating disorders are still considered perturbed. The relationship is complex. Up until very recently it has been completely normal for models and entertainers to employ very restrictive and unhealthy regimens for their bodies. It is the culture in that aspect of society to do so. In this way, psychology and biology override social norms, but simultaneously social norms are overriding biology and psychology. How would you classify this case based upon your current argument?