In 1992, a cross-sectional questionnaire study of package truck driver
s in one company was conducted at four widely scattered sites througho
ut the US; 317 drivers participated, representing 82% of those eligibl
e. The package truck drivers scored significantly above the US working
population comparison norm on all summary and individual scales deriv
ed from the SCL 90-R, indicating a substantial increase in psychologic
distress for this group. The Global Severity Index, the best single s
ummary measure of psychological distress in the SCL 90-R, revealed a m
ean T score for the drivers of 64.20, 91st percentile of the normative
population. The group perceived significantly more daily stressful ev
ents than the average working adult, and their sensitivity to these ev
ents was also increased. Role overload, a component of the Occupationa
l Str-ess Inventory was the most consistent factor associated with sym
ptoms of psychological distress on multiple regression analysis. This
study suggests that job stress is a psychological health hazard for th
ese drivers. (C) 1997 Wiley-Liss, Inc.