Testing the Paleolithic-human-warfare hypothesis of blood-injection phobia in the Baltimore ECA Follow-up Study--towards a more etiologically-based conceptualization for DSM-V

J Affect Disord. 2007 Jan;97(1-3):1-4. doi: 10.1016/j.jad.2006.06.014. Epub 2006 Jul 24.


Objective: The research agenda for the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-V) has emphasized the need for a more etiologically-based classification system, especially for stress-induced and fear-circuitry disorders. Testable hypotheses based on threats to survival during particular segments of the human era of evolutionary adaptedness (EEA) may be useful in developing a brain-evolution-based classification for the wide spectrum of disorders ranging from disorders which are mostly overconsolidationally such as PTSD, to fear-circuitry disorders which are mostly innate such as specific phobias. The recently presented Paleolithic-human-warfare hypothesis posits that blood-injection phobia can be traced to a "survival (fitness) enhancing" trait, which evolved in some females of reproductive-age during the millennia of intergroup warfare in the Paleolithic EEA. The study presented here tests the key a priori prediction of this hypothesis-that current blood-injection phobia will have higher prevalence in reproductive-age women than in post-menopausal women.

Method: The Diagnostic Interview Schedule (version III-R), which included a section on blood and injection phobia, was administered to 1920 subjects in the Baltimore ECA Follow-up Study.

Results: Data on BII phobia was available on 1724 subjects (1078 women and 646 males). The prevalence of current blood-injection phobia was 3.3% in women aged 27-49 and 1.1% in women over age 50 (OR 3.05, 95% CI 1.20-7.73). [The corresponding figures for males were 0.8% and 0.7% (OR 1.19, 95% CI 0.20-7.14)].

Conclusions: This epidemiological study provides one source of support for the Paleolithic-human-warfare (Paleolithic-threat) hypothesis regarding the evolutionary (distal) etiology of bloodletting-related phobia, and may contribute to a more brain-evolution-based re-conceptualization and classification of this fear circuitry-related trait for the DSM-V. In addition, the finding reported here may also stimulate new research directions on more proximal mechanisms which can lead to the development of evidence-based psychopharmacological preventive interventions for this common and sometimes disabling fear-circuitry disorder.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adult
  • Age Factors
  • Baltimore
  • Biological Evolution*
  • Blood*
  • Bloodletting / psychology
  • Brain / physiopathology
  • Cross-Sectional Studies
  • Diagnostic and Statistical Manual of Mental Disorders*
  • Fear / physiology
  • Female
  • Humans
  • Injections / psychology*
  • Male
  • Marriage / psychology
  • Middle Aged
  • Phobic Disorders / classification
  • Phobic Disorders / epidemiology*
  • Phobic Disorders / physiopathology
  • Phobic Disorders / psychology
  • Reproduction / physiology
  • Sex Factors
  • Urban Population
  • Warfare
  • Wounds and Injuries / psychology