Neurotypicality, normality and psychopathology

The life-history model of psychopathology (e.g. Del Giudice 2016) postulates that certain disorders are associated with the fast end or the slow end of life-history strategy.  Dark triad traits (psychopathy, narcissism, and Machiavellianism) would be more typically found on the fast end (early puberty) of life history (higher-risk-taking, less empathy). ASD people would more typically be found on the slow-end of the spectrum (later puberty, and they are typically the children of parents who started to have children comparatively late themselves, which has led to the erroneous assumption that ASD is due to accumulated mutations).

In my model of the evolution of life-history hunter-gatherers are on the slow end, early farmers (who had harder lives) in the middle and pastoralists, who probably had the most violent lives, on the fast end of the spectrum. The further a person lies outside the band of "normality" the less neurotypical they are and the risk of mental disorders increases: 

Our (western) world is arguably a farmer world, with its 9-5 routine jobs (farmers like to get up earlier, so 9-5 is actually a compromise with other types) and its focus on productivity and status. Of course, some aspects are more shifted towards other personality types, e.g. mainstream media and the tourist industry are often more shifted towards the high dopamine pastoralists, whereas social values such as life-long learning, tolerance of diversity and egalitarianism are more shifted towards the hunter-gatherer side of the spectrum.

Non-farmer types often struggle with typical “farmer jobs” (e.g. administrative, office jobs), as they tend to get bored easily with repetitive jobs. So they have to carve out their own niches; pastoralists types often become entrepreneurs (their own bosses), artists and performers or go for jobs farmer types tend to avoid (irregular working-hours), whereas hunter-gatherers often go for geeky jobs like software developers or university teachers, social jobs, or really create something unique that suits them.

What is interesting to note, is that the conscientious farmer types are dominated by serotonin, which makes people more aware of social norms and conform to them as well as less open towards diversity. Unfortunately for the other two personality types that create a rather narrow band of “normality”, beyond which people soon become outsiders. To name a banal example, where I live, most cars are grey, typically expensive, elegant and restricted to a few popular models. Another example: the almost uniform American suburbs.

My hypothesis is that people outside that narrow band of normality are more prone to mental disorders for a variety of reasons, ranging from lower-income and lower status to less acceptable to the point of feeling or becoming outcasts. It is therefore not surprising that ASD people show high rates of comorbidity with social anxiety, depression, suicidal ideation, and BDP.

In brief, my hypothesis is that many mental disorders are a problem of evolutionary mismatch, i.e. evolved traits become dysfunctional in a society for which they were not programmed. Of course, this might not apply to all mental disorders, like psychopathology, even though the symptoms might be aggravated through environmental mismatch. In this case, a mind that is not calibrated to the constant focus serotonin provides.

Some common signs of serotonin deficiency include:

• Depression
• Changes in sleep
• Chronic pain
• Memory or learning issues
• Anxiety
• Schizophrenia
• Problems with the body's internal clock
• Appetite issues.

Serotonin deficiency in the brain also occurs in OCD and ASD patients. 
The life-history model also explains similarities between gifted and ASD people, who both tend to be on the slow end of the spectrum. 

This model would also support Ruth Karpinski's "Hyper-brain/hyper-body" hypothesis, which states that high IQ people (typically on the slow end of the life-history spectrum) would suffer not only from some of the above mentioned mental disorders (ASD, ADHD, social anxiety) but also more often from physiological problems such as allergies and asthma. My personal assumption is that the physiological conditions are caused by heightened stress levels (cortisol), that arise for hunter-gatherer minds living in a farmer society.