A comprehensive meta-analysis of longitudinal studies has revealed that narcissism typically decreases from childhood through late adulthood.

The research, published in Psychological Bulletin, synthesized data from 51 samples with a total of 37,247 participants. The study examined three types of narcissism: agentic, antagonistic, and neurotic. Results suggest that all three types showed normative declines across the lifespan, with aggregated changes from age 8 to 77 years of d = -0.28 for agentic narcissism, d = -0.41 for antagonistic narcissism, and d = -0.55 for neurotic narcissism.

Rank-order stability of narcissism was high, with average values of 0.73 for agentic, 0.68 for antagonistic, and 0.60 for neurotic narcissism, based on an average time lag of 11.42 years. This stability did not vary significantly with age but declined as a function of time lag.

The researchers found that gender and birth cohort did not moderate the findings on mean-level change and rank-order stability. However, clinical samples showed significantly larger declines in narcissism compared to nonclinical samples.

These findings have potential implications for understanding personality development and may inform clinical approaches to narcissistic traits across different life stages. The authors noted that the meta-analytic data set included mostly Western and White/European samples, highlighting the need for more research with non-Western and ethnically diverse populations.

The study's results suggest that while narcissism does show a normative decline, mean levels remain relatively stable compared to other personality constructs. The high rank-order stability supports the consideration of agentic, antagonistic, and neurotic narcissism as personality traits.

Conflict of interest disclosures were not made available at time of publishing.