Conceptualising the social world is a critical first step in attempting to understand the aetiological role of social factors. This chapter draws on ideas developed in a previous era to suggest a theoretically informed rubric for conceptualising components of the social world to make them amenable to investigation, the focus being specifically on aetiology. The ecological notion of aetiology held by Faris and Dunham and their contemporaries eventually gave way to a focus on what they termed constitutional factors. The chapter addresses the necessity of considering distinctions between processes and conditions, levels of organisation and place and time. Care must be taken to guard against two common inferential mistakes involving multiple levels of organisation. The ecological fallacy is familiar to most investigators. The equally important converse fallacy, sometimes referred to as the atomistic fallacy, is less familiar. It results from comparing individuals and inferring causation at the group level.

This chapter argues that important contributions have been made by linking cognition, emotion and the social world with the emergence and maintenance of psychotic experiences. It discusses some of the consequences of the formulation of the concept of schizophrenia. Modern cognitive models of psychosis start by postulating continuities between psychosis and normal experience. There has been a prima facie assumption about aetiological theories in psychosis, a reductionist position placing genetic explanations at the beginning of the aetiological process. The study of single psychotic symptoms, or single types of symptom, is assisted by a clear account of the symptoms themselves. The association of stressful life events with relapse into positive symptoms is well established. The detailed study of the relationship between trauma and psychosis is in its early days, but the investigation of the emotional and cognitive processes common to trauma responses and to psychosis in the view carries considerable promise.