Both humans and animals may experience fear and stressful conditions as a result of radiation exposure's psychological and cognitive impacts. There is evidence connecting radiation exposure to neuro-inflammation, apoptosis, and the death of neural stem cells in addition to cognitive decline. The goal of this systematic review is to provide a thorough assessment of the body of research on the psychological and cognitive effects of ionizing radiation exposure during diagnosis and patient treatment. Ionizing radiation can affect people's mental and cognitive health. It can come from a variety of sources, including medical operations, nuclear accidents, and space exploration. To improve our knowledge of these consequences, this review aims to analyze the evidence that is currently available. An exhaustive exploration of various electronic databases, such as PubMed, Research Gate, Google Scholar, Academia, and Web of Science, was carried out to find pertinent research articles published in peer-reviewed publications. Studies that looked at the psychological and cognitive effects of ionizing radiation exposure were included in the study. The results were synthesized qualitatively and presented. 53 studies out of the 1000 that were found during the original search satisfied the inclusion criteria. Radiation occurrences, occupational exposure, medical imaging, and treatments were among the several sources of ionizing radiation exposure included in the examined research. Research has indicated that individuals receiving radiation therapy and diagnostic radiological procedures may encounter immediate psychological side effects, which could have an impact on mental health. The symptoms of these psychological reactions can include discomfort, nausea, exhaustion, difficulty sleeping, and shortness of breath. This research documented a variety of psychological and cognitive outcomes, such as low self-esteem, anxiety, depression, post-traumatic stress disorder (PTSD), cognitive deterioration, and dread. In situations including both acute and prolonged exposure, these effects were noted. Notably, those who were subjected to higher ionizing radiation doses for example, those who survived nuclear accidents showed signs of more severe and persistent cognitive and psychological deficits. The analysis has brought attention to the wide range of impacts that ionizing radiation can have on the mind and body. This variance can be explained by variables including individual susceptibility variations and exposure parameters like dose, duration, and frequency. Furthermore, the results emphasize that ionizing radiation can cause a variety of psychological reactions, ranging from short-term stress reactions to long-term mental health issues even at 0.0Gy. The consequences on cognition likewise show a wide range, with memory, attention, and executive function impairments among them.

Radiation surrounds every living thing on our planet. On hot days, the sun radiates, and our homes' radiators radiate as well. Radiation exposure occurs to passengers each time they board an aircraft. These identical passengers are exposed to another little dosage of cosmic radiation from the atmosphere when the plane ascends in altitude. Along with the surrounding ground, the stone that we use to construct our homes and buildings also contains natural radiation. In addition, there is radiation from medical devices like CT scans and X-rays, as well as radionuclides such as potassium, which can be present in some fruits and vegetables. The entire amount of potassium that we consume contains some radioactive potassium, and the radiation from these forms of potassium makes up some of the fundamental radiation kinds that we are continuously exposed to [55] . Radiation exposure is a necessary part of human life. Regardless of the effect, it has always existed. The question is, are we more vulnerable to anything that the reactor might release? Almost always, the risk is exceedingly minimal, regardless of how much it is increased. Paul Slovic divides risk perception into two categories: unknown risk and fear of danger. At its highest point, "dread risk" is characterized by feelings of helplessness, terror, catastrophic potential, deadly outcomes, and an unfair distribution of risks and rewards. Nuclear power and weapons get the highest scores among the attributes that comprise this component. When it comes to risks that are deemed to be novel, unobservable, and have a delayed manifestation of harm, they are classified as "unknown risks." [55].

The word is mostly employed psychologically to explain the public's emotional responses to situations with which one should rationally interact, as nearly every radiation-related story makes "conscientious" and "unprofessional" citizens feel afraid and rejected [31]. The dread that comes with being exposed to radiation can have considerably more negative effects than the radiation's real damaging effects. The mass media has shaped public perception over the last 70 years regarding the lethal consequences of radiation. For this reason, the majority of people fear radiation, and the very concept of radiation evokes negative emotions and associations. Since people have been hearing and absorbing the fact that radiation is lethal for such a long time, these terms have come to define and comprehend radiation exposure. Only when exposed to extremely high radiation levels can radiation result in death. Since natural radiation is all around us and will always exist, there is always a theoretical or epidemiological risk associated with it [42, 43]. It also serves as a natural lower bound for radiation protection in terms of dose and risk reduction due to its inevitable exposure to natural radiation. It is not justified to lower the contribution of radiation exposure below natural limitations [55]. To preserve function at all ages, cognitive function must be maintained. Cognitive skills are predictive of children's academic success, adults' professional success, and older individuals' ability to maintain their independence and general well-being. Cognitive functioning can be maintained by elements including physical exercise, education, career position, and mentally challenging activities.

Ionizing radiation exposure can have a profound effect on one's mental state. Radiation accidents can result in widespread and protracted psychological symptoms, such as PTSD, anxiety, and depression. The public's fear and rejection of radiation can be linked to false beliefs and information spread by the media. Although we cannot completely escape being exposed to radiation in our daily lives—both natural and man-made—it is crucial to comprehend the possible long-term effects of low radiation dosages. Myths and visuals about the effects of radiation exposure frequently feed people's worries. Furthermore, radiation exposure has been connected to neurodegenerative consequences and could be involved in the etiology of mental illnesses. 

All things considered, the mental effects of ionizing radiation exposure ought to be taken into account in addition to the physical health. To successfully handle the fallout from radiation disasters, the psychological effects of ionizing radiation exposure should be taken into account in addition to the effects on physical health. Examining the effects of ionizing radiation on mental health was the goal of this review. 

Using the PubMed, Research Gate, Google Scholar, Academia, and Web of Science Articles databases, a literature search was done to address the possibility that radiation exposure, even at 0.0 Gy above background dose, can have psychological effects that could ultimately lead to cognitive damage. Radiation anxiety, psychological stress from radiation, cognitive functioning and radiation, cognitive impairment and radiation, neuroinflammation and radiation, and psychological stress and cognitive functioning were among the search phrases that were covered. English-language peer-reviewed articles were the only ones selected. The data extracted and tabulated involved title, objective, result and conclusion of the research.

Individuals may experience psychological impacts from radiation exposure. Irrational worry and anxiety resulting from the public's fear and rejection of radiation can have more detrimental effects than the real physical harm caused by radiation [31]. Mental health effects such as depression, anxiety, and post-traumatic stress disorder are highly represented in populations affected by radiation disasters (Snežana and Milan 2020). The atomic bombings of Hiroshima and Nagasaki and the Chernobyl nuclear accident have shown long-term effects on the psychological and social processes of victims and their families [9]. Vulnerable populations such as children, women, clean-up workers, and migrants are particularly at risk for mental health issues in radiation-affected areas [25]. Additionally, radiation exposure can have an impact on cognitive processes and psychological functions, potentially contributing to the pathophysiology of psychiatric disorders [36]. Radiation exposure has multiple effects on the brain, behavior, and cognitive functions. It has been reported that high-dose (>20 Gy) radiation-induced behavior and cognitive aberration are partly associated with severe tissue destruction. Low-dose (<3>

3.1 Radiation Exposure Anxiety and Depression

Radiation anxiety is defined as the negative cognition regarding the potential adverse health effects following radiation exposure [26]. It is also associated with problems such as perceived stigma and discrimination. Most non-single-item measures of radiation anxiety are based on Slovic’s model of risk perception [49], which posits two psychological dimensions: dread risk and unknown risk. Radiation anxiety is a common issue among head and neck cancer patients undergoing radiation therapy. The use of thermoplastic masks for immobilization during treatment can cause significant anxiety [7]. Patients have reported various triggers of anxiety, such as claustrophobia and fear of the mask [12]. Healthcare providers need to address mask anxiety and provide support to patients. Strategies that may help reduce mask anxiety include increased communication, delivery of visual information, exposure to the mask before treatment, and increased control of music/soundtrack selection [27]. Additionally, radiation therapy can lead to acute psychological side effects, including anxiety, depression, fear, and low self-esteem. Therefore, support and care for the psychological well-being of radiation therapy patients are crucial (Forbes et al., 2022). Non-pharmacological interventions, such as biofeedback and breathing techniques, are being explored to reduce procedural anxiety during radiation therapy. Radiation emergencies can have significant psychological consequences, including depression, anxiety, and post-traumatic stress disorder [31]. Depression is a long-term effect of atomic bombings, nuclear testing, and radiation emergencies, with increased prevalence observed in individuals exposed to radiation. Infrared radiation has been shown to have antidepressant and anxiolytic effects in animal models [50]. Some patients undergoing radiation therapy for cancer may experience depression, with cognitive rand endogenous symptoms being helpful in distinguishing those with depressive symptoms [23]. Depression is not inevitable with cancer, and a personal or family history of treated depression is associated with an increased risk of depressive symptoms in radiation oncology patients [20]. 

Loganovsky and Vasilenko (2013) Investigated the genesis of depressive disorders caused by ionizing radiation and found that Depression is one of the most significant and long-term effects of atomic bombings, nuclear testing, and radiation emergencies. The participants in the accident at the Chornobyl nuclear power plant increased prevalence of depression (18.0% and 13.1% in controls) and suicide rates. Depression is mainly observed in the structure of an organic mental disorder against cerebrovascular disease. The clinical pattern is dominated by asthenoadynamic and asthenoapathetic depression. Depressive disorders in radiation emergencies are multifactorial, that is the result of exposure to complex psychogenic and radiological accident factors, the impact of traditional risk factors, somatic and neurological diseases, genetic predisposition, predisposition, etc. At the same time, exposure to ionizing radiation is a factor in the genesis of depression. This impact can be direct (to the Central Nervous System), and indirectly through the somatic and neurological abnormalities (multiorgan dysfunction) as well as by a variety of pathogenic mechanisms of ionizing radiation on the brain that have been discovered recently. It is strongly necessary for analytical clinical and epidemiological studies with verification of depression and evidence-based establishment of the role of radiation and non-radiation risk factors. In another investigation, it was documented the trajectory of situational anxiety during HNC treatment delivery and explored radiation therapists’ (RTs’) ability to identify it. Participants with Head and Neck Cancer commencing radiation therapy completed the state-trait anxiety inventory at their mask-making session, and once each week immediately before and after their radiation treatment. Treating RTs independently rated their perception of participant’s anxiety at the same time points. Participant- and RT-rated anxiety scores were calculated at each time point together with the proportion of participants reporting clinically significant anxiety (state-trait anxiety inventory ≥ 40). Intraclass correlations were calculated to assess concordance between participant- and RT-ratings. Sixty-five participants and 16 RTs took part in the study. Participants were classified into 1 of 5 trajectory groups: stable high (16%), increasing (19%), decreasing (27%), fluctuating (19%), and no anxiety (19%). Nearly half (43%) of participants reported clinically significant anxiety before their mask-making session, and between 30% and 43

Radiation-induced cognitive impairment is a significant concern for brain cancer survivors and individuals exposed to radiation. Several studies have explored strategies to mitigate the risk of cognitive dysfunction. One approach involves targeting Toll-like receptor 9 (TLR9) and mitochondrial reactive oxygen species (mtROS) to prevent endothelial damage and dysfunction. Another potential mitigating agent is EUK-207, a catalytic ROS scavenger that has shown promise in mitigating radiation-induced cognitive injury. Additionally, hippocampal sparing intensity modulated proton therapy (HS-IMPT) has been investigated as a means to reduce neurocognitive impairment. By sparing the hippocampus from high radiation doses, the risk of cognitive impairment can be significantly reduced without compromising tumor control. Modern intensity-modulated radiotherapy methods, such as LINAC-based intensity-modulated radiotherapy and helical tomotherapy, have also been shown to allow for the delivery of conformal dose distributions, potentially minimizing hippocampus impairment (Gram et al., 2023; Lindsey et al., 2022). Here are some findings for the reduction of ionizing radiation's impact on mental health

Gram et al. (2023) irradiated Mice at a dose of 15 Gy and showed cognitive impairments in the water maze probe trial. EUK-207 mitigated these impairments while not affecting the cognitive performance of sham-irradiated mice in the water maze probe trial. Thus, EUK-207 has attractive properties and should be considered an ideal candidate to mitigate radiation-induced cognitive injury. Gram et al. (2023) investigated the predicted risk of neurocognitive impairment of craniospinal irradiation (CSI) and the deliverability and effects of hippocampal sparing. The risk estimates were derived from published NTCP models. Specifically, research leveraged the estimated benefit of reduced neurocognitive impairment with the risk of reduced tumor control. For the dose planning study, a total of 504 hippocampal sparing intensity modulated proton therapy (HS-IMPT) plans were generated for 24 pediatric patients who had previously received CSI. Plans were evaluated for target coverage and homogeneity index to target volumes, the maximum, and the mean dose to OARs. Paired t-tests were used to compare hippocampal mean doses and normal tissue complication probability estimates. The median mean dose to the hippocampus could be reduced from 31.3 GyRBE to 7.3 GyRBE (p < .001), though 20% of these plans were not considered clinically acceptable as they failed one or more acceptance criteria. Reducing the median mean hippocampus dose to 10.6 GyRBE was possible with all plans considered clinically acceptable treatment plans. By sparing the hippocampus to the lowest dose level, the risk estimation of neurocognitive impairment could be reduced from 89.6%, 62.1%, and 51.1% to 41.0% (p < .001), 20.1% (p < .001) and 29.9% (p < .001) for task efficiency, organization, and memory, respectively. Estimated tumor control probability was not adversely affected by HS-IMPT, ranging from 78.5 to 80.5% for all plans. The estimates of potential clinical benefit in terms of neurocognitive impairment were presented and demonstrate the possibility of considerably reducing neurocognitive adverse effects, minimally compromising target coverage locally using HS-IMPT.

Table 2: Some findings on mitigating the impact of ionizing radiation

In conclusion, the systematic review of the psychological and cognitive effects of ionizing radiation exposure underscores the critical importance of understanding the multifaceted impact of such exposure on human well-being. The body of research analyzed in this review provides valuable insights into the intricate interplay between radiation exposure and the human psyche. The review has highlighted the substantial variability in the psychological and cognitive effects of ionizing radiation. This variation can be attributed to factors such as the dose, duration, and frequency of exposure, as well as individual differences in susceptibility. Additionally, the findings emphasize that ionizing radiation can induce a range of psychological responses, from acute stress reactions to long-term psychiatric disorders. The cognitive effects also exhibit a diverse spectrum, including impairments in memory, attention, and executive functions. Furthermore, it is evident from this study that the psychological and cognitive effects of ionizing radiation are not limited to the individual alone. The impact extends to families, communities, and societies as a whole. This emphasizes the necessity of adopting a holistic approach to address the psychosocial consequences of radiation exposure. Several studies have explored strategies to mitigate the risk of cognitive dysfunction as indicated in this review. The review also underscores the need for continued research in this field, particularly in the assessment of long-term and low-dose radiation exposure. Understanding the delayed effects and cumulative impact of radiation on psychological and cognitive well-being remains an important avenue for future investigation. In practical terms, the findings call for the development of comprehensive support systems and interventions for individuals exposed to ionizing radiation. Such initiatives should encompass not only the physical health but also the psychological and cognitive well-being of those affected. Moreover, raising awareness about the potential psychosocial consequences of radiation exposure is vital in promoting resilience and mitigating the stigmatization often associated with such exposure. Finally, this systematic review illuminates the intricate relationship between ionizing radiation exposure and its psychological and cognitive effects. It highlights the importance of recognizing and addressing these psychosocial consequences, not only to support affected individuals but also to foster a deeper understanding of the broader implications for society as a whole. As our understanding of this field continues to evolve, so too must our efforts to ameliorate the psychological and cognitive burdens borne by those exposed to ionizing radiation.