Cancer is among the leading causes of morbidity and mortality worldwide, profoundly affecting patients' lives at every level. While considerable advances have been made in understanding and treating the biological aspects of cancer, its psychological and psychiatric impacts remain a major concern. Psychiatric disorders, including depression, anxiety, post-traumatic stress disorder (PTSD), and adjustment disorders, are frequently observed in cancer patients. These disorders are not only common but also underdiagnosed, as their symptoms are often misinterpreted as normal emotional reactions to the illness. This misperception undermines the recognition of significant psychiatric conditions that require targeted interventions. Still, psychiatric disorders in cancer patients are not merely secondary complications but may actively contribute to poor oncological outcomes. For instance, stress and depression can directly affect tumour biology through neuroendocrine and immune mechanisms, including increased inflammatory responses and dysregulated cortisol levels, via the chronic activation of the Hypothalamic-Pituitary-Adrenal axis (HPA). Indirectly, psychiatric symptoms can impair treatment adherence and lead to lifestyle choices that increase the risk of recurrence, such as poor nutrition, lack of physical activity, or substance use.
The pathophysiology of cancer-related psychiatric disorders is multifactorial and is related to several neuropsychological and neurobiological factors. Specifically, dysregulation of biology in cancer patients might confer greater vulnerability to psychiatric disorders. The production of cytokines associated with cancer appears to play a role in the development of depression. Tumours trigger an inflammatory response that leads to the release of pro-inflammatory cytokines, including IL-6, TNF-α, CRP, and IL-1ra. These cytokines influence central nervous system function and disrupt the regulation of the HPA axis, contributing to psychological symptoms such as depression, fatigue, sleep disturbances, and appetite loss. Since tumour-related inflammation emerges early in the progression of cancer, depression and other psychological symptoms might manifest as initial indicators of the disease.
Moreover, psychiatric symptoms in cancer patients are often accompanied by neuropsychological alterations including deficits in memory, executive function, and attention. Compared to other individuals with psychiatric disorders, cancer patients may experience more severe cognitive impairments which can be exacerbated by cancer treatments, including surgery, chemotherapy, and radiotherapy. These treatments stimulate cytokine production by nearby non-cancerous cells and immune cells activated in response to treatment-induced cell death, thereby driving systemic inflammation.
Cancer profoundly affects not only patients but also their families, who often bear the emotional and caregiving burden. Being close to a loved one with cancer can lead to significant psychological distress, including anxiety and depression, among family members and caregivers. The ripple effects of this burden underscore the need for a holistic approach to mental health in oncology.
Given the background presented so far, identifying and managing psychiatric comorbidities in oncological patients is crucial. However, there are several difficulties in assessing these patients. First, there is a need to better understand the psychopathology behind cancer. Frequently, symptoms like depression and anxiety are conceived as normal reactions to cancer, whereas cancer can trigger severe syndromes, which are frequently overlooked. Second, studies related to common biological patterns linking cancer and psychiatric disorders are poorly investigated. Furthermore, there is a lack of studies that assess the effectiveness and safety of pharmacological and non-pharmacological treatments in these patients.
Family members of cancer patients experience significant emotional and psychological strain, yet their psychiatric symptoms are often overlooked. The biological underpinnings of these symptoms in caregivers, as well as effective treatments tailored to this population, are under-researched. Addressing the mental health needs of families is essential to improving overall care outcomes in oncology.
This multifaceted interplay between cancer and psychiatric disorders necessitates a comprehensive, interdisciplinary approach to understanding, diagnosing, and treating these conditions effectively.
