Celebrities are in a privileged position. When they speak, people tend to listen. This was certainly the case this week when Rosanna Davison remarked in an interview in the Irish Independent that, "a huge proportion of preventable diseases are attributable to a deficiency in certain nutrients".
Nothing controversial about that. What caused a bigger stir were her follow-up comments on non-coeliac gluten sensitivity, and her citation of “research that shows gluten to be the bad guy responsible for a huge range of medical conditions from autism spectrum disorders to schizophrenia to arthritis”. The subsequent social media backlash has been far from pretty, with her comments referred to as scientifically unfounded and even dangerous.
The link between gluten sensitivity and autism spectrum disorders is tenuous at best. Yes, there are a few case reports and small studies here and there. The economist Ronald Coase once said that, “If you torture the data long enough, it will confess”; in a similar vein, it is possible to find a peer-reviewed paper to support almost any scientific argument.
Moreover, we have heard worrisome and spurious claims before in relation to the causes of autism and, if we learn anything from experience, all published research needs to be treated with caution and is often best contextualised by an expert.
Schizophrenia, meanwhile, has long been the subject of myth. The popular but erroneous idea still exists that schizophrenia is “Jekyll and Hyde” split personality. In reality, it is a complex psychological illness in which an individual’s thoughts and perceptions become detached from reality. The four key psychotic features in schizophrenia are hallucinations (hearing or seeing things that aren’t there), delusions (fervently believing things that aren’t true), thought disorder (mixed-up thinking that makes communication very difficult) and negative symptoms (social withdrawal, speaking less and dropping out of work or education). Around one in 100 babies born will eventually develop the illness, usually between the ages of 15 and 40. So, could gluten sensitivity really be the responsible “bad guy”?
The causes of schizophrenia are a matter of well-researched theory. Although certain risk factors make you vulnerable to schizophrenia, you will probably not develop it without key stressors. Genetics makes you vulnerable, in that certain genes seem to run in families where a few relatives have acquired schizophrenia (although there is no single specific gene). Key stressors include interpersonal conflict and street drugs, especially cannabis.
There is limited and conflicting evidence in relation to gluten sensitivity and schizophrenia. Small studies published in the 1950s found a link between reduced supply of wheat and rye during World War II and a lower incidence of first-episode psychosis. Subsequent epidemiological research in Denmark has found that coeliac disease predates schizophrenia in some patients, while other studies have found slight improvements in the psychotic symptoms of a subgroup of patients on a gluten-free diet. Other research has refuted these findings, while the studies overall are limited in number and often of poor quality.
Still, Ms Davison is not necessarily wrong in her assertions about gluten sensitivity and schizophrenia. The problem lies in the emphasis. Many readers will accept at first glance what they read. For individuals with schizophrenia – and their families – comments representing gluten as the “bad guy” in schizophrenia will be met with bemusement, perplexity and – for some – misplaced hope.
This is where the danger begins. Up to 25 per cent of individuals with schizophrenia stop taking some or all of their medications within ten days of leaving hospital. This figure rises to 50 per cent within a year and 75 per cent within two years. Medication is the single most important factor that prevents relapse of psychosis. But people do not like taking medication and when alternative “natural” options are overhyped, a proportion of individuals will understandably opt for them instead, often to their detriment.
The real key to recovery lies in early intervention, with referral for assessment involving a psychiatrist and their multidisciplinary team. Medication is usually essential for targeting symptoms but, given the reluctance many people have to taking medication, the choice should be agreed fully with the individual so that their recovery goals are central. Also important are cognitive behaviour therapy (CBT), structured rehabilitation courses, a good working relationship with the team and the avoidance of street drugs. A supportive family is often the best resource an individual with schizophrenia has, so it is not surprising carer information courses have a strong evidence base internationally.
Diet certainly plays an important role. The World Health Organisatio n recently highlighted the worrying statistic that individuals with schizophrenia have a life expectancy reduced by some 10-25 years. Suicide accounts for only a fraction of this. Heavy smoking is 2-6 times more common among people with schizophrenia, while obesity exists in 45-55 per cent and diabetes in 10-15 per cent. However, most doctors and dieticians would advocate a low fat diet high in fibre rather than placing the emphasis on gluten-free options.
No doubt there are many people who feel the benefit of a gluten-free diet. But it is important that we take celebrity endorsements of the “simple cure” with a pinch of salt. This is especially true when more novel approaches may displace treatments that have a much firmer basis in science. Recovery from psychosis has a number of ingredients. It remains to be seen whether it should be gluten free.
For more information, see stjohnofgodhospital.ie; detect.ie; shineonline.ie
Dr Stephen McWilliams is a consultant psychiatrist and author. He is clinical lead of the Psychosis Programme at Saint John of God Hospital, Stillorgan, Co Dublin.
