Recently, there has been increasing focus on prevention of mental illness,early intervention and the promotion of mental health. The socialdeterminants of health and public health approaches are considered key.Early intervention has focused on psychotic disorders but prevention hasnot. This may in part reflect the fact that public health planners do nothave a clear model for how social determinants influence the risk ofdeveloping a psychotic illness. Drawing on biological, genetic andepidemiologic evidence regarding the relationship between social riskfactors and psychosis, this paper outlines a conceptual framework forunderstanding how individual and ecological factors contribute and interactto modulate the risk of developing psychotic illness. The framework assertsthat there are four dimensions: individual factors; ecological factors; theinteraction between individual and ecological factors; and time. It may helpthose considering interventions to understand the multilevel andmultifactorial effects of social factors on the aetiology of psychoticillness, to develop targeted strategies for the prevention of psychoticillness and serve as a template for the assessment of initiatives.