This is because the causes of stress-related ill health are usually extremely complex and linking conditions to specific types of work activity would be very difficult.
Mae hyn oherwydd bod achosion iechyd gwael sy'n gysylltiedig â straen fel arfer yn gymhleth iawn a byddai'n anodd iawn cysylltu cyflyrau â mathau penodol o weithgarwch gwaith.