At what level do you think "quality of life" is negatively impacted by iq? Please explain.

Tough Question. I do not believe quality of life can be correlated with iq. I have many patients from group homes with varying levels of mental retardation and mental illnesses who appear to be quite joyful and delight those around them. I also know several high IQ individuals who suffer from depression and lack of joy in life. My personal opinion is that many other factors besides IQ are most important in life.
Either High or Low. Potentially, people with with high or low iqs may struggle with quality of life. Assuming you are talking about lower iqs, people tend to start having increased problems with quality of life once the IQ gets into the borderline range. Clearly, as one moves onto the types of mental retardation, quality of life tends to go down significantly.