The Environment of Schizophrenia

Innovations in Practice, Policy and Communications

Richard Warner

• Publisher: Routledge
• Year: 2003
• ISBN:
  9781134595457
• Edition: 1
• Topic: Psychologie
• Subtopic: Psychothérapie

There is now a body of evidence suggesting that the occurrence and course of schizophrenia are affected by a variety of environmental factors. The Environment of Schizophrenia draws upon our knowledge of these factors in order to design innovations that will decrease its incidence and severity, while enhancing the quality of life for sufferers and their relatives.
Examining environmental forces operating at the individual, domestic and broad societal levels, Richard Warner proposes feasible interventions such as:
* education about obstetric risks
* marketing effective psychosocial treatments
* business enterprises set up to employ people with mental illness
* cognitive-behavioral therapy for psychosis
The Environment of Schizophrenis suggests practical ways to create a better world for those who suffer from this serious illness and for those who are close to them. It will prove fresh and stimulating reading for mental health managers and policy makers, as well as psychiatrists, clinical psychologists, mental health advocates, and communications specialists.

Part I
Individual level

Chapter 1
Obstetric complications

A genetic predisposition to schizophrenia may be present in as many as 7 to 10 per cent of the population. This is the assumption made by genetic researchers doing linkage studies (Wang et al., 1995; Freedman et al., 1997). Yet, as mentioned in the Introduction, the illness becomes manifest in no more than 1 per cent of the population (Warner and de Girolamo, 1995). Since only a fraction of those genetically at risk develop the illness, we have to assume that either it takes more than one gene to cause the illness or that the addition of an environmental factor is necessary. We know, in fact, that non-genetic, environmental factors are essential, because, despite being genetically indistinguishable, the identical twin of someone with schizophrenia has only a 50 per cent chance of developing the illness, not a 100 per cent chance (see Figure I.3). Preeminent among these causative environmental factors, it emerges, are complications of pregnancy and delivery.

A review and meta-analysis of all the studies conducted prior to mid-1994 on the influence of obstetric complications, reveals that complications before and around the time of birth appear to double the risk of developing schizophrenia (though this apparent effect could be inflated by the tendency for journals to publish studies with positive results) (Geddes and Lawrie, 1995). Since this analysis was published, more recent studies have shown similar results. Studies using data gathered at the time of birth from very large cohorts of children born in Finland and Sweden in the 1960s and 1970s reveal that various obstetric complications double or triple the risk of developing schizophrenia (Hultman et al., 1999; Dalman et al., 1999; P.B.Jones et al., 1998). A recent American study shows that the risk of schizophrenia is more than four times greater in those who experience oxygen deprivation before or at the time of birth, and that such complications increase the risk of schizophrenia much more than other psychoses like bipolar disorder (Zornberg et al., 2000).

Obstetric complications are a statistically important risk factor because they are so common. In the general population, they occur in up to 40 per cent of births (the precise rate of occurrence depending on how they are defined) (McNeil, 1988; Geddes and Lawrie, 1995; Sacker et al., 1996). They are, therefore, a much more prominent cause of schizophrenia than maternal viral infection, which probably explains no more than 2 per cent of cases of the illness (Sham et al., 1992). The authors of the meta-analysis estimate that complications of pregnancy and delivery increase the prevalence of schizophrenia by 20 per cent (Geddes and Lawrie, 1995).

The obstetric complications most closely associated with the increased risk of developing schizophrenia are those which induce fetal oxygen deprivation, particularly prolonged labor (McNeil, 1988), and placental complications (P.B.Jones et al., 1998; Hultman et al., 1999; Dalman et al., 1999). Early delivery, often provoked by complications of pregnancy, is also more common for those who go on to develop schizophrenia, and infants who suffer perinatal brain damage are at a much increased risk of subsequent schizophrenia (P.B.Jones et al., 1998). Trauma at the time of labor and delivery, and especially prolonged labor, is associated with an increase in structural brain abnormalities—cerebral atrophy and small hippocampi—which occur frequently in schizophrenia (McNeil et al., 2000).

Ironically, these complications are particularly common among infants who already have a high risk for developing schizophrenia— the children of people who themselves suffer from the illness. For people with schizophrenia, the risk that any one of their children will develop schizophrenia approaches 10 per cent, and, where both parents suffer from the illness, the risk for each child is close to 50 per cent (Gottesman, 1991). (See Figure I.3.) But this hazard is compounded by the fact that women with schizophrenia are more likely than other women to experience complications of pregnancy. For women with schizophrenia, the risk of premature delivery and of bearing low birth-weight children is increased by as much as 50 per cent (Bennedsen, 1999; Sacker et al., 1996). This is to a great extent a result of the fact that women with schizophrenia (and other psychiatric illnesses) receive less adequate prenatal care than others in the general population (Kelly et al., 1999).

The increased risk of complications for pregnant women with schizophrenia could also be due to their higher rates of smoking, to their use of alcohol and other substances, or to poverty. It might, theoretically, also be caused by a gene which increases the risk of both schizophrenia and obstetric complications, but this does not appear to be the case. One group of researchers point out that the increased risk of obstetric complications occurs when the mother, but not the father, suffers from schizophrenia; a genetically determined risk of obstetric complications and schizophrenia would not be confined just to the mother (Sacker et al., 1996). Another group points out that a genetic link between obstetric complications and schizophrenia is unlikely because there is no increase in risk of obstetric complications in those who have a family history of schizophrenia (and, therefore, a greater likelihood of carrying a gene for the illness) (Marcelis et al., 1998). Whatever the cause, the result of the obstetric complications is to further increase the risk of schizophrenia in the offspring of women with schizophrenia.

On a positive note, there is good evidence that improved obstetric care can lead to a lower incidence of schizophrenia. The large majority of recent epidemiological studies looking at changes in the incidence of schizophrenia in countries around the world indicate a substantial decrease in the occurrence of the illness since the Second World War. Several studies from Britain, Scandinavia and New Zealand reveal a decrease in the incidence of schizophrenia of the order of 40 to 60 per cent over 10- to 15-year time-spans during the period from the late 1960s to the late 1980s (Warner and de Girolamo, 1995). It is unclear, however, to what extent the apparent decline is an artifact resulting from changes in diagnosis and treatment patterns.

It is possible, for example, that, as diagnostic practices change, fewer patients with a psychotic illness are being labeled as suffering from schizophrenia and more are being labeled as having bipolar disorder. Similarly, fewer cases of schizophrenia may have been detected in recent years because more are being treated in the community and are never admitted to hospital. While it is likely that such artifacts as these explain some of the apparent decrease in the incidence of schizophrenia, it is not at all clear that they explain all of it, and a real drop in the occurrence of the illness appears possible (Warner and de Girolamo, 1995).

Many researchers argue that, if real, the explanation for the declining occurrence of schizophrenia in the developed world is the improvement in obstetric care in the postwar period. The decline in the occurrence of schizophrenia in England and Wales parallels a decrease in the infant mortality rate, with a twenty-year delay—just what one would expect for an illness which begins, on average, around age 20, if improvements in obstetric care were responsible for the change (Gupta and Murray, 1991). If the quality of obstetric care and a reduction in complications are important in bringing about changes in the incidence of schizophrenia, this would help to explain why the decrease has been greatest in the most prosperous regions of Britain (Gupta and Murray, 1991), and why the districts showing no decrease are those with high rates of poverty and large immigrant populations (Eagles, 1991). Obstetric complications are more common among the poor and immigrants; children born to Afro-Caribbean immigrants, for example, are more likely to be of low birth weight than those in the general population (Terry et al., 1987; Griffiths et al., 1989).

It seems probable, therefore, that minimizing obstetric complications will lead to further reductions in the occurrence of schizophrenia, particularly if we target those who are at greatest risk for bearing children who will develop the illness.

Intervention no. I
An educational campaign on the risks of obstetric complications

We could decrease the incidence of schizophrenia by educating people with schizophrenia and their relatives (particularly those of or approaching child-bearing years) about the added risk of schizophrenia from complications of pregnancy and delivery which contribute to perinatal brain injury. Prospective mothers should be cautioned that smoking in pregnancy or maternal illnesses such as diabetes and heart disease may contribute to chronic fetal hypoxia and increase the risk of schizophrenia in the offspring. Where one or both parents has a family history of schizophrenia, obstetricians should be aware that fetal oxygen deprivation, prolonged labor, placental complications and conditions of pregnancy leading to early delivery and low birth weight may present an added risk of schizophrenia to the newborn later in life. In such cases it would be appropriate to establish a low risk-threshold for the use of caesarian section and to take aggressive precautions to prevent early delivery and low birth weight.

One of the most effective interventions would be to ensure that all women with schizophrenia get adequate prenatal care, which is the opposite of what currently happens (Kelly et al., 1999). Several studies have shown that the provision of adequate prenatal care leads to better obstetric outcomes and fewer low birth-weight babies. For example, the babies of cocaine-using women in New York who attended four or more prenatal appointments were half a pound (a quarter of a kilogram) heavier, on average, than those whose mothers attended three appointments or fewer (Racine et al., 1993). Similarly, the birth weight of babies of cocaine users who were enrolled in a comprehensive program of prenatal care in Chicago was more than a pound and a half (three-quarters of a kilogram) greater than for women who had made two or fewer prenatal visits (MacGregor et al., 1989). The same benefits of prenatal care accrue to the infants of mothers who are not cocaine users (Zuckerman et al., 1989).

To avoid creating undue concern, the educational efforts suggested here should make it clear that the risk to a person who is a first degree relative of someone with schizophrenia, of bearing a child who will develop the illness, is not frighteningly high. As indicated in the Introduction (see Figure I.3), the risk is increased from the general population rate of 1 per cent to around 2 to 5 per cent, (because the infant will be a second-degree relative of the person with schizophrenia) but the risk may be reduced by averting complications of pregnancy and delivery.

To provide the necessary education, we could:

• establish an international panel of psychiatric epidemiologists and obstetricians to review the current data on obstetric complications and the risk of schizophrenia and write a report that includes recommendations for obstetric counseling and practice;
• publish the panel report in major obstetric and psychiatric journals;
• produce and distribute informational brochures summarizing the recommendations so that they can be placed in waiting rooms of mental health agencies throughout the developed world;
• train junior doctors in primary care, psychiatry and obstetrics to provide genetic and obstetric counseling to people with schizophrenia and their families.

With such an intervention, we could decrease the number of people who suffer from this dreadful illness, the associated suffering of family members and the enormous costs to society.

Chapter 2
Substance use

Mental health professionals in the United States have generally been more concerned about the use of street drugs and alcohol by people with schizophrenia and other serious mental illnesses than have professionals in Europe. In the US, the issue has been termed a “crisis” (V.B.Brown et al., 1989), and American psychiatric journals often carry articles on the topic. Is this an American over-reaction, or is the concern justified?

Frequency of use

In fact, the frequency with which people with schizophrenia use drugs of abuse is greater in the US. A recent study shows that people with serious mental illness in Bologna, Italy, are substantially less likely than those in Boulder, Colorado, to have used a variety of substances (Fioritti et al., 1997). Only a quarter of the people with mental illness from Bologna used marijuana at some time in their lives compared to nearly 90 per cent of subjects in Boulder. The use of hallucinogens, stimulants, narcotics and solvents by people with mental illness is also higher in Boulder (see Table 2.1).

In general, these differences for people with mental illness match differences in the market availability of illicit drugs in the two countries. The only substances more commonly abused by people with mental illness in Bologna are over-the-counter preparations. However, even the abuse of alcohol and the inhaling of solvents, glue, paint and gasoline, although these substances are all equally available in Italy, are more frequent among people with mental illness in Boulder than in Bologna. It is likely that the greater use among the American patients matches patterns of use in the general US population. Over 30 per cent of American adults between the ages of 19 and 30, for example, use marijuana, and nearly half that number are using cocaine (Johnston et al., 1989). In addition, the life circumstances of people with mental illness in Boulder, which, as we shall see in Chapter 5, are distinctly different from those in Bologna, may contribute to their elevated use of substances. For example, the heavy use of marijuana by people with mental illness in Boulder was associated with being unemployed and lacking other daily activity (Warner et al., 1994), and in both countries substance use was often reported to be an attempt to reduce boredom.

Table 2.1Lifetime frequency of substance use by people with serious mental illness in Bologna, Italy and Boulder, Colorado (per cent)

Do people with schizophrenia use more substances?

It seems to be true that people with schizophrenia use more drugs than others in the population. In one large study of mental disorder carried out in several American cities, the Epidemiologic Catchment Area (ECA) study, the prevalence of substance abuse at some time in the person’s life was as high as 47 per cent of people with schizophrenia, compared to 17 per cent of people in the general population (Regier et al., 1990). Similarly current substance abuse rates in different samples of Americans with schizophrenia, running at 30 to 40 per cent (Atkinson, 1973; Safer, 1985), are substantially higher than the ECA rate of 15 per cent (Regier et al., 1990).

There is less agreement, however, about which drugs tend to be used more by people with schizophrenia. Two different reviews of the literature conclude that people with schizophrenia tend to use hallucinogens and stimulants (like amphetamines and cocaine) more than do people in the general population, but they disagree about whether marijuana use is greater. Both reviews conclude that the use of alcohol, sedatives and narcotics is no greater among people with schizophrenia (Mueser et al., 1990; Schneier and Siris, 1987).

It is clear that people with schizophrenia smoke more tobacco than others. In an Irish study, for example, more than 80 per cent of subjects with schizophrenia smoked cigarettes, compared to less than 40 per cent of the general population, and those who smoked were likely to be heavy users and to smoke high-tar brands (Masterson and O’Shea, 1984). In a recent Scottish study, nearly 60 per cent of people with schizophrenia were smokers, compared to under 30 per cent of the general population, and those who smoked were heavy smokers (McCreadie and Kelly, 2000). The authors of the Scottish study concluded that people with schizophrenia were spending around a quarter of their income on cigarettes and, given the high sales tax on tobacco in Britain, that the tax revenue from their smoking covered anywhere from a fifth to a third of the direct costs of treating schizophrenia in Britain. Needless to say, this heavy smoking increases health hazards such as emphysema, tho...

Table of contents

• Cover Page
• Title Page
• Copyright Page
• Figures and Tables
• Acknowledgements
• Introduction: What Is Schizophrenia?
• Part I: Individual Level
• Part II: Domestic Level
• Part III: Community Level
• Summary and Conclusions
• Bibliography