Birth cohort increases in psychopathology among young Americans, 1938-2007: A cross-temporal meta-analysis of the MMPI

Two cross-temporal meta-analyses find large generational increases in psychopathology among American college students (N = 63,706) between 1938 and 2007 on the MMPI and MMPI-2 and high school students (N = 13,870) between 1951 and 2002 on the MMPI-A. The current generation of young people scores about a standard deviation higher (average d = 1.05) on the clinical scales, including Pd (Psychopathic Deviation), Pa (Paranoia), Ma (Hypomania), and D (Depression). Five times as many now score above common cutoffs for psychopathology, including up to 40% on Ma. The birth cohort effects are still large and significant after controlling for the L and K validity scales, suggesting that the changes are not caused by response bias. The results best fit a model citing cultural shifts toward extrinsic goals, such as materialism and status and away from intrinsic goals, such as community, meaning in life, and affiliation. (C) 2009 Elsevier Ltd. All rights reserved.