Consideration of violence from the perspective of public
health is long overdue. 1 Combining approaches of
neurotoxicology, behavioral biology, and epidemiology
reveals that environmental factors ignored by social
scientists can help explain variation in rates of violent
crime within the U.S. as well as violence in a global
perspective.
For example, because lead is a neurotoxin that
interferes with dopaminergic function and weakens
behavioral inhibition, 2 average levels of lead are often
higher in children with ADD/ADHD 3 as well as in
violent offenders.4 Because manganese has
parallel effects (lowering serotonergic as well as
dopaminergic function), counties with industrial
pollution with either lead or manganese (as measured
by the EPA’s Toxic Release Inventory) have higher rates
of violent crime. These contributions of exposure to
heavy metals remain statistically significant controlling
for socio-economic and demographic factors, with an
interactive effect making the presence of both toxins
worse than mere addition of their separate effects on
violence.5 Temporal variations in lead exposure also
matter as is evidenced by a reduction in violent crime in
the U.S. associated with the ban on leaded gas. 6
Such effects often reflect synergistic interaction among
risk factors. In addition to toxic releases of manganese
and lead, recent research shows untested toxins in
public water supplies interact with exposure to lead
paint from old housing as factors associated with
higher rates of violent crime.7 Moreover, minorities --
probably due to low calcium intake in diets -- are
significantly more vulnerable to these effects. 8
Whereas sociologists and political scientists are
ill-prepared to understand the complex nexus linking
violent crime to neurotoxins, individual susceptibility,
development, and physical as well as social
environment, such findings are consistent with the
conception of "population health."9 To further such
research and link it effectively with public policy,
however, our universities need more emphasis on
interdisciplinary studies.
References
1 . Mercy JA, Krug EG, Dahlberg LL, Zwi AB. Violence
and Health: the United States in a Global Perspective.
Am. J. Pub. Health, 2003:93:256-261.
2 . Cory-Slechta DA, Brockel BJ, O’Mara DJ, Lead
Exposure and Dorsomedial Striatum Mediation of Fixed
Interval Schedule-Controlled Behavior, NeuroToxicology
2002:23:313-327.
3 . Minder B, Das-Smaal EA, Brand, EF, Orlebeke JM,
Jacob F. Exposure to lead and specific attentional
problems in schoolchildren. Journal of Learning
Disabilities. 1994: 27:393-98; Tuthill RW. Hair lead
levels related to children's classroom attention-deficit
behavior. Archives of Environmental Health. 1996:
51:214-20.
4. Needleman HL ed., Human Lead Exposure Boca
Raton: CRC,1989; Stretesky PB,. Lynch MJ, The
Relation Between Lead Exposure and Homicide, Arch.
Pediat Adoles/ Med 2001:155: 579-582.
5. Masters RD, Hone B, Doshi A. Environmental
Polution, Neurotoxicity, and Criminal Violence in Rose
J (ed.) Environmental Toxicology London: Gordon &
Breach, 1998: 13-48.
6. Masters RD, Biology and Politics, in Polsby N (ed.)
Ann. Rev. Pol. Sci 2001:4:353-356.
7. Masters RD, Coplan MJ, Hone BT, Dykes JE,
Association of Silicofluoride Treated Water with
Elevated Blood Lead, Neurotoxicology,
2000:21:1091-1100.
8. Masters RD. Social Implications of Evolutionary
Psychology: Linking Brain Biochemistry, Toxins, and
Violent Crime. In Bloom RW, Dess NK (eds.)
Evolutionary Psychology and Violence 2003. N Y.:
Praeger/Greenwood.
9. Kindig D, Stoddart G. What Is Population Health?
Am J. Pub. Health 2003:93:380-383.