The risk of self-harm after incident psychiatric disorder diagnosis in patients with 26 cancer types and the risk of unnatural deaths after self-harm was examined in 459,542 individuals. Using data from primary care practices and hospitals, the total burden was quantified and not just the first event of psychiatric disorder and self-harm. The prevalence of mental health diagnoses before and after self-harm demonstrates that previous diagnoses of psychiatric disorders are important predictors of self-harm. Prevalence ratio is higher among younger individuals, as they are more likely to be referred for specialised psychosocial cancer care. Patients with depression had the highest risk of self-harm, especially within 12 months of diagnosis, suggesting higher vigilance needed during this initial critical period. The risk of suicide and other causes of death was significantly higher in patients who harm themselves, particularly within 12 months of the first self-harm episode. The findings are published on 28 March 2022 in the Nature Medicine by Alvina G. Lai of the Institute of Health Informatics, University College London in London, UK.
Patients with cancer may experience substantial psychological distress due to neuropsychiatric effects exerted by tumours, adverse reactions to physically demanding cancer treatment and substantial social and emotional impact from cancer and its sequelae. Cancer leaves permanent pathological alterations that imprint on people’s lives even when signs of active disease are no longer present. Patients with preexisting mental health conditions may be prone to relapse during the cancer journey, whereas individuals without a history of mental health may face competing demands from cancer that could distract physicians from recognising and diagnosing psychiatric disorders.
Information on the total burden of psychiatric disorders across all common adult cancers and therapy exposures is scarce. It prompted the authors to estimate the risk of self-harm after incident psychiatric disorder diagnosis in patients with cancer and the risk of unnatural deaths after self-harm.
Depression was the most common psychiatric disorder in patients with cancer. Patients who received chemotherapy, radiotherapy and surgery had the highest cumulative burden of psychiatric disorders. Patients treated with alkylating agent chemotherapeutics had the highest burden of psychiatric disorders, whereas those treated with kinase inhibitors had the lowest burden.
All mental illnesses were associated with an increased risk of subsequent self-harm, where the highest risk was observed within 12 months of the mental illness diagnosis. Patients who harmed themselves were 6.8 times more likely to die of unnatural causes of death compared with controls within 12 months of self-harm (hazard ratio [HR] 6.8; 95% confidence interval [CI] 4.3–10.7). The risk of unnatural death after 12 months was markedly lower (HR 2.0; 95% CI 1.5–2.7).
The authors outlined several limitations of their study. They have not considered tumour stage and grade due to insufficient data. They acknowledged the possibility of surveillance bias between patients with psychiatric disorders and in those without. Although the use of population-based records provides robust and representative data, there remains a risk of underreporting of self-injurious behaviour due to stigma. The analyses were adjusted for socioeconomic deprivation to reduce the impact of the biases. The effects of psychiatric interventions on cancer survivorship can be explored in the future.
The authors underlined that an evidence-based care guideline of the Cancer Care Ontario Program for the management of depression in adult patients with cancer proposed specific recommendations: 1. to screen patients with cancer for depression, 2. to provide psychoeducation, destigmatise depression and investigate medical contributors to depression (e.g. vitamin B12, iron and folate levels and hypothyroidism), 3. to provide pharmacologic and psychological interventions, 4. to assess depression severity and follow stepped care approach, 5. to consider collaborative care interventions involving oncologists, primary care practitioners and psychiatrists, 6. to refer to mental health specialists when there is a risk of self-harm, 7. to consider psychological therapies such as cognitive behavioural therapy, and 8. to consider the use of antidepressant medication for severe depression.
Disruptive behaviour in patients with psychiatric illness may interfere with cancer treatment and continuing care. Unlike mental health physicians, oncologists may not receive adequate training in dealing with behavioural problems, and there has been limited guidance on managing clinical and legal risks associated with these clinically complex scenarios. Multidisciplinary support for the primary physician is crucial, especially in the ambulatory oncology setting.
The authors concluded that the patients with both cancer and mental illness experience premature mortality and are at greater risk of self-harm. They provided an extensive knowledge base to help inform collaborative cancer-psychiatric care initiatives by prioritising patients who are most at risk.
Alvina G. Lai is supported by funding from the Wellcome Trust, National Institute for Health Research University College London Hospitals Biomedical Research Centre, National Institute for Health Research Great Ormond Street Hospital Biomedical Research Centre and Academy of Medical Sciences.
Reference
Chang WH, Lai AG. Cumulative burden of psychiatric disorders and self-harm across 26 adult cancers. Nature Medicine; Published online 28 March 2022. DOI: https://doi.org/10.1038/s41591-022-01740-3