Schizophrenia usually caused by child abuse?

THERE are a couple of psychologists who think that child abuse is a significant cause, if not the major cause, of schizophrenia and began strongly publicizing this theory recently. However main-stream schizophrenia researchers say that there are no rigorous studies that support this theory.

Increasingly however, psychiatric researchers do seem to think it is likely that child abuse is one of the causal factors in schizophrenia (especially for people biologically or genetically predisposed) - though as yet there is no definitive proof for this.

Research does support the idea that social stress and family stress may play a roll in development of schizophrenia - especially for people who are biologically or genetically predisposed.

Therefore it is reasonable to suspect that child abuse could significantly increase the risk of schizophrenia for a child predisposed to schizophrenia (and certainly child abuse - including neglect, emotional, physical and sexual abuse - is very harmful and has a lasting negative impact on a child's mental health), but there is no rigorous evidence to support Hammersley and Read's theory that child abuse causes a significant portion or "the majority" of cases of schizophrenia. Certainly, however, we think it is an area where more research needs to be done.

Following is detail on the theory and an analysis on what we believe are the errors that the psychologists have made in developing their theory:

Drs. Paul Hammersley (University of Manchester) and John Read (University of Aukland, NZ) argue that two-thirds of people diagnosed as schizophrenic have suffered physical or sexual abuse and thus believe it is shown to be a major, if not the major, cause of the illness. With a proven [see analysis of this "proof" below] connection between the symptoms of post-traumatic stress disorder and schizophrenia, they say, many schizophrenic symptoms are actually caused by trauma.

They suggest that their evidence includes 40 studies [see analysis and flaws identified in using these 40 studies below], which they think revealed childhood or adulthood sexual or physical abuse in the history of the majority of psychiatric patients and a review of 13 studies of schizophrenics [that they think] found abuse rates from a low of 51% to a high of 97%. Psychiatric patients who report abuse are much more likely to experience hallucinations – flashbacks which have become part of the schizophrenic experience and hallucinations or voices that bully them as their abuser did thus causing paranoia and a mistrust of people close to them.

They admit not all schizophrenics suffered trauma and not all abused people develop the illness, but believe less traumatic childhood maltreatment, rather than actual abuse, may be an important difference. In their review of the 33,648 studies conducted into the causes of schizophrenia between 1961 and 2000, they found that less than 1% was spent on examining the impact of parental care. Still, they say, there have been enough studies to suggest negative or confusing early care may be an important addition to abuse as a cause.

Genes may still have a role to play but other evidence Hammersley and Read cite shows that genes alone do not cause the illness. A recent study compared 56 adoptees born to schizophrenic mothers with 96 adoptees whose biological parents did not have the illness. The families were observed extensively when the children were small and all the adoptees were assessed for psychiatric illness in adulthood. It was found that if there was a high genetic risk and it was combined with mystifying care during upbringing, the likelihood of developing schizophrenia was greater - genes alone did not cause the illness.

In response to this theory Leading experts in schizophrenia have said the following (from New Scientist magazine):

Following is a more indepth-analysis of the review article in which the theory was recently proposed:

Childhood trauma, psychosis and schizophrenia: a literature review with theoretical and clinical implications

Schizophrenia Research Reviews, by Demian Rose, MD, PhD - a review of the article:

Introduction: Schizophrenia is a neurodevelopmental disease for which no clear cause is known. Historically, many theories have been put forth to explain its genesis. During the middle part of the 20th century, one popular theory was that of the “schizophrenogenic mother”, which postulated that schizophrenia was a result of an upbringing wherein a child was given “consistently inconsistent” parenting, leading to a difficulty with discerning reality from fantasy. This theory was rightly condemned as an oversimplified explanation, and subsequently discarded.

The question of how one’s early developmental experiences influence the expression of mental illness remains, however, an area of vigorous academic debate. With the primacy of the so-called biopsychosocial model of psychiatry over the past several decades, this debate has moved away from a strictly “nature vs. nurture” paradigm to one that respects the intertwined nature of genes, environment and behavior. It is clear that environmental experiences literally reshape our brains. It therefore seems likely that this reshaping process could lead a vulnerable individual to develop a disorder that he or she would not have developed if the circumstances had been different.

While this conceptualization of mental illness is generally accepted by the field, we are still without much experimental data to describe the degree to which such factors influence specific disorders, or the mechanisms by which brain changes might occur. This review article attempts to synthesize many studies on childhood abuse (sexual and physical) and come to a conclusion about the relative causality of such early experiences with regards to schizophrenia.

Who did the review: The first author of this review is a psychologist in New Zealand who has previously published books and papers relating to childhood abuse and has also designed programs meant to improve the ability of mental health care providers to ask about and assess patient trauma histories.

Why they did the review: The authors of this review clearly have an agenda. To be fair, they are quite open about this agenda, and claim that the data will support it. In short, what the authors wish to convey is that:

    (1) Current conceptions of schizophrenia as a brain illness, as opposed to one with a large psychological component, have garnered too much sway in modern psychiatry;

    (2) in assuming schizophrenia is “biological”, psychiatrists often overlook the possibility of early trauma as a causal factor and

    (3) psychiatry will often attribute psychosis due to trauma as “non-psychotic” post-traumatic stress disorder (PTSD), instead of calling a duck a duck, i.e. in their view correctly diagnosing trauma-induced psychosis as schizophrenia.

What they investigated: The authors present a literature review that summarizes several dozen research studies that examined the relationship between childhood abuse and psychiatric disorders or other mental health outcomes. They summarize studies that show a relationship between child abuse and “schizophrenic symptoms” in Table 3. Most of their discussion relates to this data set, and the casual reader could get the “gist” of this article by reading its first page, last page and the text relating to Table 3.

What they argue: The authors make a strong claim. They assert that “child abuse is a causal factor for psychosis and schizophrenia”. They use this claim as the basis of their recommendation that “researchers and clinicians should routinely ask about childhood trauma when trying to understand or assist people diagnosed as psychotic or schizophrenic”. [italics mine]

In essence, the authors attempt to provide support for the argument that psychiatry and psychology have been ignoring the “social” basis of psychosis. They further argue that this problem is worst for schizophrenia itself, with many clinicians often ignoring social and psychological factors that could be important in its genesis.

The take-home message: I was frankly a bit angered by the authors’ consistent usage of schizophrenia as synonymous with hallucinations.

This point bears repeating: the authors consistently use the terms psychosis, hallucinations, paranoia and schizophrenia in a manner different from that of most researchers.

In my opinion, this consistent misuse of terminology was essentially a verbal shell game that allowed the authors to use each term as it benefited their own hypotheses. For example, they seem to ignore the fact that their own summary tables, while supporting a correlation between early abuse and hallucinations, do not suggest a link between childhood trauma and negative and cognitive symptoms, important aspects in the diagnosis of schizophrenia. In another example, they describe hallucinations and paranoia as “schizophrenic symptoms”, instead of correctly describing them as “symptoms commonly (but not always) seen in schizophrenia”. As a review that tries to integrate data from the past 100 years, a profound semantic flaw that the authors do not address is the fact that the definition of schizophrenia as a psychiatric disorder has evolved much over the past century. Even the term “psychosis” was for the first half of this century used to refer to a theoretical construct that has since been shown to have no supporting data.

The authors are technically honest at certain times in the article, such as when they admit that “our paper may have more implications for the occurrence of psychosis in other illnesses [than schizophrenia]”. But my overall feeling was of being hoodwinked from the very beginning, with the authors cleverly using the word schizophrenia in quotes within their first summation point. One must dig through the text to later find that they are referring not to the current diagnostic criteria for the disease, but rather to data such as the “schizophrenia scale”, part of a commonly given personality test that is typically not used diagnostically, or to their own conception of the “schizophrenia construct” (whatever that means).

I did find some of the authors’ points thought-provoking and possibly even clinically useful – e.g., I agree that clinicians often assume that childhood abuse must lead to PTSD and probably therefore at times “forget” about schizophrenia. But taken as a whole, their argument that “child abuse is associated with severe mental illness and psychotic symptoms, and since schizophrenia is a severe mental illness with psychotic symptoms, it is likely due to child abuse” is unsupported by the data that the authors themselves present as supportive. In my mind, the authors confuse the issue instead of clarifying it.

Allow me to summarize some points that the authors should have made clear:

Therefore, I believe that the authors overstate the causal relationship between child abuse and schizophrenia by equating psychosis, specifically hallucinations, with the syndrome of schizophrenia itself.  

Posted by szadmin (at schizophrenia.com) on June 16, 2006

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