According to a survey conducted by a Canadian university, workers in sales and service and the white collar occupations are more likely to be depressed than blue collar workers. The authors of the survey suggest that blue collar workers often have to deal only with machines or other physical objects, while sales personnel and white collar workers have to deal with people, who are far more unpredictable. The uncertainty over whether or not they are pleasing their clients and customers causes stress among such workers, and that stress eventually causes depression. White collar workers are also forced to make abstract decisions whose results can never be known in advance, while blue collar workers can fix concrete problems and see the results immediately. "You're never sure if you're doing the right thing or the wrong thing," says management professor Vish Baba. "It has to be judged by the consequences that come later."

Critics of the survey suggest that white collar workers simply have more time to reflect on their job dissatisfaction, due to the enforced passivity of the typical cubicle dweller's workday.

Other factors have an effect on depression. Working nights, for instance, causes more depression than working at day, largely because of its disruption of the sleep cycle. About 4 percent of the survey's respondents, all between the ages of 25 and 64, claimed to be depressed.

"White-Collar Workers The Most Sad" from The Hamilton Spectator
"Depressed about work? It's all about perspective" from The Toronto Gazette