By Dr David Laing Dawson
The studies cited by Bruce Wilson do not demonstrate a causal relationship between childhood trauma (neglect, abuse, deprivation, sexual abuse) and schizophrenia. They do, quite logically, demonstrate a relationship between childhood trauma and severity of the course of schizophrenia. That is, the specific injuries to cognitive developmental processes, focus, attention, arousal systems, and affective pathways in the brain caused by serious childhood neglect and/or abuse, (if this person later develops schizophrenia or bipolar disorder), cause a more refractory and debilitating form of the illness. The trauma experienced may also shape the nature and form of the symptoms.
Abuse and neglect in childhood make schizophrenia worse.
And then we have “Lies, damn lies, and statistics”:
Some studies show, for instance, when adults are hospitalized with a diagnosis of schizophrenia, and asked or surveyed about childhood trauma (specifically physical abuse, emotional abuse, emotional neglect, physical neglect, sexual abuse) they answer in the affirmative between 7 percent for sexual abuse and 13 percent for emotional neglect and a total of 49 percent overall. Now these figures turn out to very similar to the same percentages we find when we survey the entire population. In fact when the definition of trauma is expanded to include major losses, bullying, witnessing a death, the percent of the general population answering in the affirmative is more than 80% even in countries like the US.
In the general population 15 to 25% of women and 14% of men report being sexually abused as children or teens.
So if I simply take these figures from legitimate studies I could make a case that a smaller percentage of people suffering from schizophrenia report being abused than the general public. (e.g., for sexual abuse, 7% of schizophrenics vs. 15%+ of general population) . At the very least I can certainly say that these studies do not show a causative link between abuse and schizophrenia. In fact I can use these figures to support the opposite conclusion.
But for years it has been known that identical twins raised in the same household are only concordant for schizophrenia 60 to 80% of the time. This does imply that an environmental influence could make a difference for 40 to 20%. (My own small sample of identical twins (2) with schizophrenia over 50 years places concordance at 100%)
But if the twins are raised in the same household they must have had similar environments and experiences through childhood and adolescence. It is rather inconceivable that one identical twin was abused and/or neglected and the other not.
So this presented a puzzle.
But now we know that a.) 99.7 percent of the DNA of every human is identical, b.) that human DNA is 96% percent the same as that of chimpanzees and c.) identical twins do not have exactly the same DNA and d.) expression of any gene can be influenced by many factors (including other genes), many of which are probably intrauterine. For example, identical twins can develop similar but not identical finger prints.
Epigenetics and environmental factors certainly play a role in the onset, development and the course of any genetic illness. There also always have been, and continue to be, problems, differences, and great variability in the diagnosis of schizophrenia, making most surveys involving this diagnosis suspect. And the onset of trouble (early symptoms) can be well hidden in a protective, adaptive environment, or explode early in a troubled home.
And it is my experience that the immediate “environmental factors” that precipitate a full blown schizophrenic psychosis in a person genetically vulnerable to schizophrenia are not “traumas”, but (besides drug use) rather common, normal, usual developmental social stresses: Attending high school, leaving home to live on campus, share a student house, first job, first date, first relationship, first child, even the push and expectation to advance developmentally and socially…
And by the time identical twins reach the age of schizophrenia onset there may easily have been a sufficient number of different epigenetic and environmental factors to offer, 20% of the time, protection for one and not the other. (And a more productive line of research might be to figure out what those protective factors are)
As I have been reminded recently, serious trauma in the first few years of life (neglect, deprivation, abuse, sexual abuse) causes enormous damage that is readily apparent in the years of childhood and adolescence long after the child has been rescued. Let us not trivialize this level of trauma by including disappointment, unhappiness, failure at sports, having to change schools, growing up poor, name calling, loss of a friend, or even of a parent, under the rubric of TRAUMA.