CLINICAL HANDBOOK OF SCHIZOPHRENIA

76 I. CORE SCIENCE AND BACKGROUND INFORMATIONThe underlying conceptualization is that these early events might sensitize the personexperiencing them, such that later events would trigger an episode of schizophrenia. Thecurrent view is that the early events might change an individual’s propensity to interpretthe world in an adverse way (i.e., might instill negative schemas about the self and others—the world being a dangerous place, for instance). These early events often involve victimization,such as child sexual abuse and bullying at school. There is certainly growing evidencefor links between distant traumatic events and the later onset of schizophrenia.However, the interaction between early and more recent events has not yet been demonstrated.Thus, it has not clearly been shown that early environmental events confer vulnerabilityor whether this is primarily biological, cognitive or emotional, or an interactioneffect. However, early life events do seem to increase later risk.Again, we are faced with the problem of specificity. Child sexual abuse is also commonin people with anxiety, depression, substance abuse, and personality disorder, althoughsome studies have indicated the association may be particularly strong in schizophrenia.Studies of mechanism may help here. The mechanism of the association betweenearly events, particularly sexual abuse, and later schizophrenia may involve processessimilar, but certainly not identical, to those involved in the generation of posttraumaticstress disorder (PTSD). Thus, people with schizophrenia who have experienced child sexualabuse or other violent trauma tend to have more hallucinations than those withoutsuch experiences; hallucinations are defined as intrusive mental events with some similaritiesto reexperiencing phenomena in PTSD.Some psychosocial contexts may not only increase the risk of certain types of eventsbut also influence the interpretation of events and, indeed, of ordinary social interactions.One example is the position of immigrants, particularly if they are illegal or seeking asylum.Such people have often experienced horrible events due to war or political oppressionin their country of origin, and arrive in the host country with vulnerabilities alreadyset up. This may be confirmed by the experience of being treated with suspicion by localpeople and with ill-disguised scorn from officialdom. In these circumstances, a degree ofparanoia may indeed be adaptive, and a Forrest Gump–like openness or naivete might bedisastrous. Given this scenario, it is hardly surprising that disadvantaged immigrantgroups seem to have much higher rates of psychosis than the host population. There are anumber of possible explanations for this finding, but increasing credence is currently accordedto psychosocial interpretations based on empirical research (i.e., that adverse environmentsrather than biological differences are a key feature).SOCIAL NETWORKSOther psychosocial contexts may affect the way individuals interpret their environment.People with schizophrenia commonly have impaired social networks—small primarygroups and inadequate social support. This has generally been interpreted as a directconsequence of either their disorder or its prodromal features, such as socialwithdrawal. However, one of the key functions of social networks, particularly confidingrelationships, is that of cognitive triangulation: People try out their ideas in conversationwith friends and confidantes. This usually leads to the pruning of their more bizarreideas. In other words, within limits, conversation keeps them sane, and socialisolation does the opposite. The first emergence of delusional ideation often occurs inthe context of a period of isolation, whether other- or self-imposed. The possibility thatisolation is associated with delusion formation and the emergence of anomalous experiencesrequires longitudinal studies. At present we just have the evidence that isolation