The environmental roots of mental illness are no delusi

The extent of the harm in childhood pranks remains to be investigated, with much more research to be done, but the impact of difficult experiences have been shown to shape perception, and even the brain itself.

Mimi's classmates took her bag and hid it. The architects of "operation bag swipe" found the whole episode hilarious but their thinly concealed mirth turned Mimi's distress to despair. Searching in all the wrong places, the 10-year-old's search was met with misinformation and conspiratorial silence. Poor little Mimi began to feel like a victim again. She found her bag, but not until a teacher begrudgingly intervened and brought an end to the "harmless" prank.

The harmlessness of such pranks is debatable, especially if repeated often enough. The experience of victimisation is an important factor in the development of severe and enduring mental health problems. Psychologists have explored the different ways in which people interpret such experiences, or how we explain them to ourselves. Some of us will provide ourselves with internal explanations for negative events: "I failed the exam because I'm stupid." While others will tend to provide themselves with more externally focused explanations: "I failed the exam because the teacher is incompetent." The way we explain these events contribute to our psychological development and maintenance.

Delusions, for example, are one of the defining symptoms of psychotic illness. Delusions are basically false beliefs that are resistant to facts that disprove them. They tend to centre around a small number of themes; grandiosity, guilt, love, jealousy and most common of all paranoia, the belief that other people are planning to do you harm. Research has found that low or unstable self-esteem, and defensive explanatory styles are particularly characteristic of patients experiencing paranoid symptoms. It is easy to see how repeated victimisation experiences might lead to both.

Epidemiological evidence provides further support for this idea. Numerous large-scale surveys undertaken in several nations, including Mexico, Germany and the Netherlands all suggest victimisation experiences are predictive of paranoia. Consider also the finding that in the UK, people of Afro-Caribbean and Asian origin are disproportionately more likely to be diagnosed as suffering from paranoid delusions. Interestingly, the rate of mental illness for those living in the Caribbean is not as high so genetic inheritance cannot serve as the cause. People of Afro-Caribbean decent living in predominantly white areas of the UK also appear to be at far greater risk of paranoid delusions than those living in predominantly Afro-Caribbean areas. Richard Bentall, a professor of psychology in the UK, suggests that victimisation occurs more frequent amongst minority groups who may often experience harassment, humiliation, and discrimination.

Despite the common sense, and potential utility of these psychosocial insights, research and clinical practices have remained overly fixated on biological approaches to psychosis. The quest to solve the ancient puzzle of madness is too often a hunt for predisposing genes, structural brain abnormalities, and neurochemical imbalances. The reality is that genetic research into severe mental illness has born no fruit whatsoever in terms of prevention or intervention. Similarly the search for structural and neurochemical causes has proven equally inconclusive.

Consider for example that in the psychotic illness known as "schizophrenia" certain areas of the brain (the ventricles) are sometimes enlarged compared to the brains of "normals". This might be taken as evidence of some kind of organic disease process at work. However, enlarged ventricles are not unique to schizophrenia, and the brains of people who have experienced sexual abuse in childhood show similar structural abnormalities even in the absence of any psychotic symptoms. The bottom line is that difficult life experiences like trauma, victimisation and separation can bring about physical changes in brain structure. So any structural differences observed in schizophrenia are just as likely to be consequences of difficult experiences, as they are to be causes of the proposed illness. Perhaps the elusive pathogen (disease causing organism) responsible for schizophrenia is man himself. Ironic, the cause of an illness, searching in vain for the cause.

For her part, Mimi survived school and her many victimisation experiences. She grew up to be a happy, healthy, well-balanced individual and now works as a school counsellor. She is keen to ensure that the next generation of children in the UAE experience the same kind of gains in mental health that their parents enjoyed in terms of physical health and longevity. At for the moment, there is much more to be done.

Justin Thomas is a psychologist and assistant professor in the department of health sciences at Zayed University in Abu Dhabi