The psychological consequences of (perceived) ionizing radiation exposure: a review on its role in radiation-induced cognitive dysfunction.

Reference: Collett, G., Craenen, K., Young, W., Gilhooly, M., and Anderson, R.M. (2020) The psychological consequences of (perceived) ionizing radiation exposure: a review on its role in radiation-induced cognitive dysfunction. International Journal of Radiation Biology. Advance online publication. https://doi.org/10.1080/09553002.2020.1793017

Background to research

Maintaining good cognitive functioning is important for people of all ages. For example, it is important for school performance in children, work performance in adults, and important for undertaking daily tasks and for the quality of life in older adults. Cognitive functioning essentially means your brain skills and includes memory, reaction time, and problem solving. Cognitive functioning generally becomes worse as you get older, but some factors may also help preserve your cognitive functioning. One example of this is physical activity. There are also several factors which may accelerate cognitive decline or cause worse cognitive functioning. These can include certain genes, stress, and lifestyle factors such as excessive alcohol consumption and cigarette smoking. Another possible factor for worse cognitive functioning is exposure to ionizing radiation. This can happen in certain settings such as nuclear power plant accidents, radiotherapy in hospitals, certain job roles, and space travel. The effects of high doses (≥ 1.0 Gy) of ionizing radiation on cognitive functioning are fairly well-understood, while the consequences of low (≤ 0.1 Gy) and moderate doses (0.1 – 1.0 Gy) have been receiving more research interest over the past decade.
 
In addition to any impact of actual exposure on cognitive functioning, believing that you have been exposed to ionizing radiation is known to increase anxiety about the effect on your health and also your descendants’ health. This anxiety is a form of psychological stress and may itself impact cognitive functioning Accordingly, at low doses both actual and perceived exposure have a potential to impact cognitive functioning.
 

What did the research involve?

We reviewed published studies which indicated a potential for ionizing radiation and the related psychological stress to impact cognitive functioning. We focused specifically on low and moderate doses of ionizing radiation and present current understanding based upon the studies examined.
 

What were the research questions?

The key question that we ask is whether perceived radiation exposure - where the radiation dose is no higher than the background doses - can result in psychological stress, which could in turn lead to worse cognitive functioning. We highlight the interplay between these psychological stress mechanisms and those mechanisms which arise in response to known exposures and question how together they may impact cognitive functioning.
 

What did we find?

Overall, the evidence shows prenatal exposure to low and moderate doses of ionizing radiation can cause problems to brain development and subsequent cognitive functioning, but the evidence for adolescent and adult low- and moderate-dose exposure causing similar problems remains uncertain.

Although there is some evidence for biological effects of actual low-dose exposure, the persistent psychological stress from the worry of low-dose exposure in adulthood may pose a greater threat to our cognitive functioning than the actual exposure itself.

It appears that there could be some similarities in the ways ionizing radiation and psychological stress can affect cognitive functioning. For instance, inflammation may be relevant for both psychological stress and low dose ionizing radiation exposure which can subsequently affect cognitive functioning. We highlight the importance of this for scientists in estimating the impact of low doses of ionizing radiation on cognitive functioning.
 

Who did the research?

Researchers in CHRC.

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