“The Dunedin Study”: Early Indicators of Schizophrenia, by Kirsteen Mclay-Knopp


Continuing  our series of articles on findings discovered by the “Dunedin Longitudinal Study”

The Dunedin Study’s findings on predictability early in childhood of a later onset of schizophrenia, are revolutionary… and potentially life changing.  Before we continue, however, here is a description of the mental health condition known as “schizophrenia”:

When a person has schizophrenia they go through patches where it is hard to think clearly, manage their emotions, distinguish what is real and what is not, and relate to others.  They may have times when they lose contact with reality. This can all be very frightening.  Schizophrenia most often begins between the ages of 15 and 30 years, occurring for the first time slightly earlier in men than in women. Schizophrenia happens in approximately the same numbers across all ethnic groups. The onset of schizophrenia can be quite quick. Someone who has previously been healthy and coped well with their usual activities and relationships can develop psychosis (loss of contact with reality) over a number of weeks. That said, symptoms may also develop slowly, with the ability to function in everyday life declining over a number of years.  The course of schizophrenia is very variable.  Everyone experiences it differently and most will make a reasonable recovery, going on to lead a fulfilling life. About one third of people experiencing schizophrenia will have ongoing problems, perhaps with continuing symptoms such as hearing voices.   [Source:  Mental Health Foundation of New Zealand].

This illness is serious then, both in its effects on the individuals with schizophrenia and on those who live with them.   The Dunedin Longitudinal Study asked participants whether they had ever heard voices or seen things which were not there.  The participants, born in 1972-1973, were asked this question at the age of 11 years.  Twenty-five years later, it was discovered that, of those participants who said they had heard voices or seen things which were not there, half had then gone on to develop schizophrenia.  Prior to this study, children had never been asked about such things.  There had never, previously, been any measured indicator of schizophrenia in children and it was assumed that it was an “adult disease” (beginning somewhere between the ages of 15 and 30 years, as indicated in our definition, above).   This is a major breakthrough, as it means we are now able to identify children at risk of developing schizophrenia and intervene with help for those who need it earlier, before their whole lives are affected.


Following on from this, The Dunedin Study hopes to identify why 50% of children with “indicators” did not then go on to develop schizophrenia… and whether there might be a “nurture” component which makes individuals with indicators more vulnerable.  Many children have “imaginary friends” and play elaborate, imaginary games which seem almost “real” in their developing minds.  As well as this, we have the influence of social media, movies and television.  However, the difference between imaginative play versus “hearing voices” and “seeing things” which are not there is a concern when these are early indicators of schizophrenia in 50% of those who experience them.

Participants found to have a shorter version than normal of the 5HTT Seratonin Transporter gene had a higher incidence of clinical depression and attempted suicide.  (There have even been arguments made that this should be a marker when making decisions such as whether or not a child should be removed from a damaging home situation).  With regards to schizophrenia, it was discovered that those with this shorter than normal 5HTT were more likely to present with the disease as adults if they used cannabis.  (This was also dependent on how young participants were when they began using cannabis and how long their use was continued… younger use and higher rates of use dramatically increases chances of schizophrenia, when participants also had the 5HTT gene).


Another test done by The Dunedin Study on participants at age 38, found that adults who had been diagnosed as having schizophrenia had wider venules (very small veins) at the back of their eyes than those who had not been.  The only other group with wider than normal eye venules were those participants who had high blood pressure.  This has led to the understanding that “blood flow” is an accurate measure of schizophrenia– not only blood flow in the eye venules, but also general blood flow all over the brain.  This lends itself to the question of whether the difference in blood flow (between those who have and those who do not have schizophrenia is a “cause or effect” of the disease.  Current research would tend to suggest it is causal.

In the USA alone, about $50 million is spent annually on support for those with schizophrenia.  If the vascular (blood flow) theory is correct, the next step would be to develop possible ‘treatments’ or preventative measures from early on in life (reacting to indicators in children).  One possible treatment would involve oxygen supplementation for children identified as having wider venules at the back of their eyes, plus indicators (hearing voices, seeing things which aren’t there).

As an interesting side finding, participants in The Dunedin Study who were found, at age 38, to have wider venules at the back of their eyes also tended to have a lower IQ as children.  This implies that prevention of wider venules in those deemed at risk could also help alleviate a range of other related and currently untreatable issues.   As in the case of those children who presented as being at risk of schizophrenia, prevention would result in a positive shift in life trajectory.

The more we look at the findings of The Dunedin Longitudinal Study, then, the more we see possibilities for the positive altering of life trajectories, if intervention occurs early.  We at The Forever Years feel excited by the future potential for a positive way forward and the sculpting of optimal life trajectories that this offers for all our children everywhere.  Aside from anything else, study findings show that “The Forever Years” (childhood) really are years which affect us for the rest of our lives not only mentally, but also physically.  The more systems are put in place to monitor our children and react to indicators of future issues at an early stage, the greater the chance we have for positive change.