BACKGROUND: Following the tenets of world polity and innovation diffusion theories, I focus on the coercive and mimetic forces that influence the diffusion of mental health policy across nations. International organizations\' mandates influence government behavior. Dependency on external resources, namely foreign aid, also affects governments\' formulation of national policy. And finally, mounting adoption in a region alters the risk, benefits, and information associated with a given policy.
METHODS: I use post-war, discrete time data spanning 1950 to 2011 and describing 193 nations\' mental health systems to test these diffusion mechanisms.
RESULTS: I find that the adoption of mental health policy is highly clustered temporally and spatially. RESULTS provide support that membership in the World Health Organization (WHO), interdependence with neighbors and peers in regional blocs, national income status, and migrant sub-population are responsible for isomorphism. Aid, however, is an insufficient determinant of mental health policy adoption.
CONCLUSIONS: This study examines the extent to which mental, neurological, and substance use disorder are addressed in national and international contexts through the lens of policy diffusion theory. It also adds to policy dialogues about non-communicable diseases as nascent items on the global health agenda.