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.