 For example, epidemiological research suggests that different cultural groups may have divergent rates of diagnosis, symptomatology, and expression of mental illnesses.There has also been increasing acknowledgment of culture-bound disorders, which may be viewed as an argument for an environmental versus genetic psychological adaptation.While certain mental disorders may have psychological traits that can be explained as 'adaptive' on an evolutionary scale, these disorders cause afflicted individuals significant emotional and psychological distress and negatively influence the stability of interpersonal relationships and day-to-day adaptive functioning.