Biomarkers in psychiatric disorders: status quo, impediments and facilitators.

World Psychiatry 22:2 June 2023 forces have pushed us to a genetic sweet spot regarding a cer­ tain trait that does not tail off gradually but, with relatively minor changes in the allele distribution, suddenly transforms into dis­ order. Many psychological traits may need to stay within narrow bounds to enable adaptive social interaction, so small variations may yield cliff­ edge disorder vulnerability. Emergent properties of specific allele combinations may exist for other unexpected reasons. For example, a recent study found that certain combinations of positively selected alleles yield­ ing cognitive advantage increased risk for autism spectrum dis­ order. Moreover, beyond alleles, at the trait level, there can be dysfunction­ causing combinations of individually selected posi­ tive traits (e.g., certain combinations of individually selected per­ sonality traits can yield personality disorders such as psychopa­ thy). All of this goes to show that it is not dimensionality per se but the way selective processes operated on various elements on a dimension that determines normality and disorder. Evolutionary psychiatry’s role thus transcends the current dis­ pute over psychiatry’s nosological future. Whichever proposal triumphs, psychiatry’s status as a medical discipline requires distinguishing normal variation from mental disorder, which rests on understanding human psychobiological design. Symp­ tom networks, extremes on symptom dimensions, and intense brain circuitry activations can be normal or abnormal depend­ ing on context. These proposals, whatever their merits, rearrange the symptomatic deck chairs on our nosological Titanic without addressing the root problem: i.e., that DSM psychiatric nosology is sinking due to lack of attention to the evolved nature of human normality, yielding invalid normal/disorder demarcations. Only evolutionary psychiatry provides a scientifically defensible answer to the fundamental nosological normal/disorder “demar­ cation” problem. Because the way people are biologically designed does not always fit social values and ideals, evolutionary psychiatry treads on potentially controversial ground. There is a tension between social idealizations – what we want to believe about ourselves and demand of our society’s members – versus the scientific reality of human nature. M. Foucault correctly observed that a society’s view of human nature tends to be distorted and permeated by its values and biases, rationalizing its efforts at social control. If psychiatry is to make scientific progress, it must understand the truth of human nature that lies beyond cultural preconceptions as a basis for valid diagnostic concepts that support psychiatric science. The promise of evolutionary psychiatry is that it is the one subdiscipline of psychiatry devoted to realizing this foundational goal.