Depression and poor mental health can significantly impact work productivity and performance. A 1990 study found that individuals with major depression had a 4.78 times greater risk of disability days and those with minor depression had a 1.55 times greater risk. Because minor depression is more prevalent, it was associated with 51% more disability days in the community than major depression. The study concludes that the threshold for identifying clinically significant depression may need to be lowered to include those with fewer symptoms but still measurable impacts. Only by changing diagnostic classifications can the true societal impact of depression be adequately addressed.