Introduction: A cancer diagnosis should not depend on a psychiatric history
Lung cancer is one of the world’s deadliest cancers, but over the past two decades, treatment has become more effective and more personalized. Surgery, chemotherapy, radiotherapy, targeted drugs, and immunotherapy have helped many patients live longer. In theory, these advances should benefit everyone who develops lung cancer. In practice, they do not.
A major new nationwide study from Japan shines a harsh light on a persistent blind spot in cancer care: patients with schizophrenia spectrum disorders, or SSD, were significantly less likely to receive several standard treatments for non-small cell lung cancer (NSCLC), the most common form of lung cancer. The study is important not only because of its size, but because it quantifies something clinicians, patients, and families have long suspected: severe mental illness can shape who gets timely, stage-appropriate cancer treatment.
This is not simply a story about psychiatry. It is a story about equity, communication, stigma, fragmented health systems, and the hidden ways medicine can fail people who already carry a heavy burden of illness.
The new study: What researchers found in Japan
The study, published in Chest in 2026 by Yamada and colleagues, analyzed national hospital-based cancer registry data linked with administrative data in Japan. Researchers examined 166,663 patients who received initial treatment for NSCLC between 2018 and 2021. Among them, 1,346 had schizophrenia spectrum disorders, defined by ICD-10 diagnoses F20-F29.
The results were striking.
Patients with SSD were more likely to be diagnosed at stage IV, meaning metastatic or advanced cancer, than patients without psychiatric disorders: 45.0% versus 31.4%. They were also less likely to undergo surgery overall: 31.5% versus 49.9%.
Even after adjusting for age, sex, cancer stage, comorbidities, and functional status, the treatment gap remained:
| Treatment outcome | Adjusted odds ratio | What it means |
|---|---|---|
| Surgery for NSCLC | 0.70 | Patients with SSD were 30% less likely to receive surgery |
| Adjuvant chemotherapy for stage II/IIIA | 0.31 | They were much less likely to receive recommended chemotherapy after surgery |
| Concurrent chemoradiotherapy for stage III | 0.99 | No significant difference was detected |
| Systemic therapy for stage IV | 0.54 | They were less likely to receive drug treatment for advanced disease |
In plain language: severe mental illness was associated with lower use of several standard lung cancer treatments, especially surgery, postoperative chemotherapy, and systemic therapy for advanced disease.
Why this matters beyond Japan
Although the study was conducted in Japan, the underlying problem is global. People with serious mental illness, including schizophrenia, die earlier than the general population, often by 10 to 20 years. While suicide and accidents contribute, a large share of this excess mortality comes from common medical illnesses such as cardiovascular disease, infections, and cancer.
Several international studies have shown that patients with severe mental illness are more likely to be diagnosed with cancer at a later stage, less likely to receive guideline-concordant treatment, and more likely to die from cancer. A 2024 Lancet Psychiatry Commission on cancer in people with mental illness argued that these disparities are not inevitable. They reflect modifiable failures in screening, access, communication, care coordination, and social support.
Lung cancer is a particularly important example because its treatment often requires quick, coordinated decisions. Depending on the stage, patients may need surgery, pathology review, molecular testing, radiation planning, smoking cessation support, and repeated clinic visits. For someone already navigating psychosis, cognitive symptoms, poverty, side effects of antipsychotic medication, or unstable housing, the system can be overwhelming.
A fictional patient story: Michael’s missed window
Michael, a 58-year-old man living with schizophrenia, has been stable for years on antipsychotic treatment. He smokes heavily, lives alone, and sees a community psychiatrist every few months. Over time, he develops a persistent cough and weight loss. He assumes it is from smoking. At one primary care visit, he struggles to describe his symptoms clearly. A chest X-ray is delayed. By the time he sees a specialist, the cancer is more advanced than it might have been months earlier.
Once diagnosed with NSCLC, new problems appear. Michael misses one appointment because transportation falls through. His sister is unsure whether she is allowed to join discussions. The thoracic surgery team worries about postoperative adherence. The oncology clinic is concerned about whether he can tolerate chemotherapy. His psychiatrist is not looped into the treatment plan. None of these concerns are trivial. But if they become excuses for therapeutic pessimism, Michael may lose his chance at standard treatment.
Michael is fictional, but the pattern is real. Many patients with serious mental illness do not fail treatment because they are uninterested or incapable. They fail because the system is not designed around their needs.
Why do treatment disparities happen?
There is rarely a single reason. More often, several barriers accumulate.
First, diagnosis may happen later. Smoking rates are disproportionately high in people with schizophrenia, which increases lung cancer risk. Yet preventive care and early symptom evaluation are often inconsistent. Symptoms may be overlooked, underreported, or mistakenly attributed to psychiatric illness, a phenomenon sometimes called diagnostic overshadowing.
Second, communication can break down. Cancer care requires informed consent, discussion of risks and benefits, and complex scheduling. Some patients with SSD may have cognitive impairment, disorganized thinking, paranoia, or low health literacy, especially during periods of relapse. But clinicians sometimes overestimate incapacity. Decision-making ability is task-specific and should be assessed carefully, not assumed absent because of a psychiatric diagnosis.
Third, cancer and mental health care are often siloed. Oncologists may feel unprepared to manage psychosis, while psychiatrists may not be integrated into cancer care. This can lead to delays, duplicated work, confusion over medications, or unnecessary exclusion from treatment.
Fourth, social circumstances matter. Poverty, unemployment, unstable housing, lack of family support, and transportation problems can all interfere with care. People with severe mental illness face these challenges more often.
Fifth, stigma still exists in medicine. Some clinicians may assume that a patient with schizophrenia will not adhere to treatment, will not tolerate surgery, or will not benefit enough to justify aggressive care. Sometimes these judgments are framed as practical concerns. But when they are not evidence-based or individualized, they become discrimination.
What the study does and does not prove
The Japanese study is strong, but it is still observational. That means it shows association, not automatic causation. It cannot fully explain why each patient did or did not receive treatment. Some patients may have declined therapy. Some may have had clinical contraindications not fully captured in administrative data. Others may have been considered too frail, despite the researchers adjusting for functional status and comorbidities.
Still, the pattern is too consistent to dismiss. When a large national dataset shows lower odds of surgery, lower odds of postoperative chemotherapy, lower odds of systemic therapy, and more frequent stage IV diagnosis in a defined patient group, that is a signal of structural inequity.
Importantly, the study found no significant difference in concurrent chemoradiotherapy for stage III disease. That result is interesting. It suggests disparities are not uniform across all treatment settings. Some treatment pathways may be more standardized or less vulnerable to discretionary variation than others. Understanding why one area appears more equitable could help improve others.
Misconceptions that can harm patients
One damaging myth is that people with schizophrenia are poor candidates for cancer treatment by default. In reality, many can successfully undergo surgery, chemotherapy, or radiation when they receive appropriate support. Psychiatric diagnosis alone should never be used as shorthand for inability.
Another misconception is that cancer outcomes are worse in this population mainly because of “patient factors.” That is only part of the story. Health systems, clinicians, and policies also shape outcomes. If appointments are hard to coordinate, if no one helps with transport, if consent processes are rushed, or if teams fail to include caregivers appropriately, poorer outcomes are partly system-produced.
A third myth is that psychiatry and oncology can be managed separately. They cannot. Cancer treatment may worsen anxiety, insomnia, or psychosis. Antipsychotics may interact with antiemetics, pain medicines, or cancer drugs. Tobacco use can alter metabolism of some psychiatric medications. Integrated care is not optional; it is clinically necessary.
What better care could look like
Reducing disparities does not require futuristic technology. Many solutions are practical.
One priority is earlier detection. People with SSD should have equitable access to smoking cessation services, primary care, lung cancer symptom evaluation, and, where appropriate, low-dose CT screening. Screening discussions should be accessible and repeated over time, not abandoned after one missed appointment.
Another priority is structured treatment support. Nurse navigators, case managers, social workers, and family members can help patients attend visits, understand plans, and manage logistics. Even simple measures such as reminder calls, transportation assistance, and same-day coordination between specialties can make a large difference.
Capacity assessment should be individualized. A patient may struggle with one complex decision yet still be able to express goals and preferences. Supported decision-making, simplified explanations, repeated conversations, and involvement of trusted caregivers can preserve autonomy while improving safety.
Psychiatric stabilization during cancer treatment is essential. Liaison psychiatry or psycho-oncology services can help manage psychosis, depression, delirium, substance use, insomnia, and medication interactions. These services should be built into cancer centers, not treated as an afterthought.
Finally, clinicians should track treatment equity. Cancer programs routinely monitor surgical outcomes and complication rates. They should also examine whether patients with severe mental illness are less likely to receive guideline-concordant therapy.
Practical recommendations for clinicians and health systems
Here are evidence-informed steps hospitals and clinicians can take now:
| Problem | Practical response |
|---|---|
| Late diagnosis | Strengthen symptom evaluation, smoking cessation, and screening access for people with serious mental illness |
| Communication barriers | Use plain language, teach-back, written summaries, and repeated visits when needed |
| Uncertain decisional capacity | Perform structured, task-specific capacity assessment; do not assume incapacity based on diagnosis |
| Fragmented care | Create routine collaboration between oncology, psychiatry, primary care, nursing, and social work |
| Missed appointments or treatment delays | Offer navigation, transportation support, caregiver outreach, and flexible scheduling |
| Medication complications | Review drug-drug interactions, smoking status, and psychiatric symptom burden throughout treatment |
| Hidden bias | Audit treatment patterns and train staff on stigma, disability rights, and equitable cancer care |
What patients and families should know
If you or a loved one has schizophrenia or another serious mental illness and is diagnosed with lung cancer, it is reasonable to ask direct questions:
What stage is the cancer?
What is the standard treatment for this stage?
Am I being offered that treatment, and if not, why not?
Would a psychiatric consultation help support treatment?
Can a family member, case worker, or trusted friend attend appointments?
Is there a nurse navigator or social worker who can help coordinate care?
These are not confrontational questions. They are the questions of informed patients.
Families and caregivers can be especially important in tracking appointments, monitoring symptoms, clarifying consent discussions, and advocating for stage-appropriate care. At the same time, patient autonomy should be respected whenever possible. The goal is not to replace the patient’s voice, but to strengthen it.
Expert perspective: equity is a quality metric
The broader message of this study is simple: equal cancer care should be a quality standard, not an aspiration. If one patient receives surgery because their support system is strong and another does not because their psychiatric illness makes the pathway harder, that is not merely unfortunate. It is a systems failure.
As the Lancet Psychiatry Commission emphasized, improving cancer outcomes in people with mental illness will require action across the continuum: prevention, screening, diagnosis, treatment, survivorship, and palliative care. The Japanese lung cancer study gives that agenda new urgency.
For oncologists, the lesson is not to become psychiatrists. It is to recognize that mental illness is part of real-world cancer medicine. For psychiatrists, the lesson is not to hand off cancer to another specialty. It is to remain engaged when a patient enters oncology. For health systems, the lesson is to stop treating severe mental illness as a complicating side note and start treating it as a core equity issue.
Conclusion
Patients with schizophrenia spectrum disorders should not have lower odds of receiving potentially life-extending lung cancer treatment simply because their care is harder to organize. The new nationwide study from Japan adds robust evidence to a troubling reality: people with severe mental illness are more likely to present with advanced NSCLC and less likely to receive several standard treatments.
The good news is that this gap is not biologically predetermined. It can be narrowed through earlier diagnosis, coordinated psycho-oncology care, individualized capacity assessment, caregiver engagement, and deliberate anti-stigma efforts in cancer systems.
Cancer care has made extraordinary scientific progress. The next step is making sure that progress truly reaches everyone.
References
1. Yamada Y, Fujiwara M, Ishii T, Watanabe T, Fujimori M, Nakaya N, Kawamura T, Otsuki K, Ichihara E, Shimazu T, Hinotsu S, Uchitomi Y, Inagaki M. Impact of pre-existing schizophrenia spectrum disorder on the receipt of surgery and other treatments for non-small cell lung cancer: A multicenter nationwide cohort study in Japan. Chest. 2026 May 20. PMID: 42167588.
2. Dalton SO, Mellemkjær L, Thomassen L, Mortensen PB, Johansen C. Risk for cancer in a cohort of patients hospitalized for schizophrenia in Denmark, 1969-1993. Schizophrenia Research. 2005;75(2-3):315-324.
3. Kisely S, Crowe E, Lawrence D. Cancer-related mortality in people with mental illness. JAMA Psychiatry. 2013;70(2):209-217.
4. Cunningham R, Sarfati D, Stanley J, Peterson D, Collings S. Cancer survival in the context of mental illness: a national cohort study. General Hospital Psychiatry. 2015;37(6):501-506.
5. Riede F, Scherer M, Lohmann A, et al. The Lancet Psychiatry Commission on cancer in people with mental illness. Lancet Psychiatry. 2024;11(5):385-436.
6. NCCN Clinical Practice Guidelines in Oncology: Non-Small Cell Lung Cancer. National Comprehensive Cancer Network. Current version available at nccn.org.
7. Sung H, Ferlay J, Siegel RL, et al. Global cancer statistics 2020: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries. CA: A Cancer Journal for Clinicians. 2021;71(3):209-249.
8. De Hert M, Correll CU, Bobes J, et al. Physical illness in patients with severe mental disorders. I. Prevalence, impact of medications and disparities in health care. World Psychiatry. 2011;10(1):52-77.