Bipolar disorder in oncology: Considerations for the psychiatrist

Abstract

Background

Bipolar disorder confers elevated cancer morbidity and mortality compared to the general population, yet bipolar disorder remains under-studied in oncology settings.

Aims

This narrative review aimed to synthesize key considerations for psychiatrists and oncologists treating people with co-occurring bipolar disorder and cancer.

Methods

A narrative review was performed to examine literature related to bipolar disorder in oncological care, focusing on outcomes, treatment-emergent mood symptoms, psychopharmacological interactions, and supportive interventions.

Results

Bipolar disorder may adversely affect cancer care through reduced treatment engagement, diagnostic delays, and lower receipt of guideline-concordant oncologic therapy. Bipolar disorder is associated with increased risks of self-harm and suicide, as is receiving a cancer diagnosis. Cancer-related neurological conditions and treatments, including corticosteroids, antineoplastics, and interferon-alpha, may precipitate or worsen mood episodes. Mood stabilizers and antipsychotics carry clinically relevant risks including organ toxicity, electrolyte disturbances, cardiac effects, and immunosuppression. Nonpharmacologic strategies, particularly psychotherapy and maintenance of sleep stability, are essential care components.

Discussion

Bipolar disorder has important implications for cancer treatment, while cancer and its therapies can destabilize mood and complicate psychiatric care. Early psychiatric care, close collaboration between oncology and psychiatry, careful medication selection and monitoring, attention to suicide risk and sleep, and psychosocial support are essential to improving care outcomes in this high-risk population. Future research addressing bipolar disorder as a distinct category within psycho-oncology rather than categorized under broader severe mental illness classifications will help further elucidate disorder-specific best practices.

1. Background

Bipolar disorder is a chronic, recurrent mood disorder defined in the DSM−5-TR by episodic mania (bipolar I disorder) or hypomania and depression (bipolar II disorder) [1]. The prevalence of bipolar spectrum disorders in the U.S. adult population is approximately 4%, corresponding to about fifteen million adults [2]. In addition to mood symptoms, people with bipolar disorder often suffer from persistent cognitive impairment in attention, memory, and executive function domains, conferring additional functional burdens [3]. Features such as cognitive deficits, fluctuating insight, and variable treatment adherence are especially relevant when bipolar disorder co-occurs with complex medical conditions such as cancer, or when cancer burden and treatment, in turn, contribute to worsened mental health.

Reviews of severe mental illness (SMI) and cancer have shown that people with bipolar disorder and other mental illnesses experience barriers to health care that extend into oncology, resulting in poorer access to cancer screening and treatment, conferring elevated risk for mortality [4]. Despite growing attention to psychological distress in oncology, bipolar disorder remains under-studied and under-recognized; large psycho-oncology datasets frequently rely on composite categories such as “mood disorder” or “serious mental illness” without specific considerations for bipolar disorder [4], [5]. Although bipolar disorder is both a mood disorder and a serious mental illness, it is distinctive in the symptom burden it confers from other mood disorders like major depression. To improve outcomes, clinicians providing care to people with bipolar disorder must consider potential impacts on cancer care, as well as how cancer and cancer care may affect mood stability. This narrative review synthesizes information on bipolar disorder in oncology for mental health clinicians and oncologists treating people with co-occurring bipolar disorder and cancer.

1.1. Impact of bipolar disorder on cancer care

People with cancer have higher prevalence rates of psychiatric disorders than the general population [6]. In a population-based cohort of 459,542 individuals with cancer, the cumulative burden of five major psychiatric disorders, including bipolar disorder, was associated with a markedly increased risk of self-harm and years of life lost compared with cancer patients without such diagnoses [5]. Evidence on whether bipolar disorder increases the risk of developing cancer is mixed but suggests a modest elevation; for instance, a U.S. sample of patients with schizophrenia and bipolar disorder combined showed a 2.6-fold higher cancer risk compared with the general population [4].

Current psycho-oncology practice guidelines emphasize routine distress screening with brief tools such as the National Comprehensive Cancer Network (NCCN) Distress Thermometer and Problem List [7]. These instruments are designed to detect general distress and depressive or anxiety symptoms; as such, they may miss or misclassify patients with bipolar disorder, as mood elevation or mixed features (e.g., features of both depression and hypomania/mania in a single mood episode) are not well captured. Moreover, these instruments were not designed or intended for people with known psychiatric disorders, and more specific instruments for depression and mania offer more specificity and sensitivity for those with known mood disorders, although false positive rates are often high (as to be expected with screening instruments).

Treatment engagement represents another challenge. Medication non-adherence to maintenance pharmacotherapy in bipolar disorder is common and clinically significant [8]. Adverse effects, limited insight, cognitive impairment, and regimen complexity contribute to non-adherence and challenge a patient’s ability to sustain and complete cancer treatment. Oncologists treating cancer in people with bipolar disorder (and mental health conditions in general) are not immune to societal stigma, so clinicians may minimize or miss physical complaints that may represent disease progression or treatment intolerance [9].

These vulnerabilities contribute to worse cancer outcomes: a cohort study in Italy of more than 12,000 individuals showed approximately 50% higher cancer mortality among those with bipolar spectrum disorders compared with the general population [10]. A systematic review of patients with pre-existing mental health disorders and cancer found delays in diagnosis, reduced likelihood of receiving guideline-recommended therapies (e.g., surgery, radiotherapy) with delays in treatment initiation, higher rates of treatment interruption, and reduced use of adjuvant therapies [11], although bipolar disorder’s impact specifically was not studied. Proactive mental health consultation at the time cancer is diagnosed is recommended in general, and especially in people with a history of a serious mental illness. As treatment progresses, active psychiatry and oncology collaboration has been found useful by clinicians and caregivers, although outcome data are limited [12].

Suicidal ideation represents a major and often underrecognized clinical risk at the intersection of bipolar disorder and cancer. Systematic reviews and meta-analyses consistently identify psychiatric illness history, depression, anxiety, pain, demoralization, financial strain, social isolation, and impaired social functioning as key contributors to SI in cancer patients as well [13]. Among oncology populations, the prevalence of suicidal behaviors varies widely, ranging from 0.7% to 46% depending on cancer type, disease stage, and assessment method [14]. Overall, cancer patients have nearly double the suicide rate of the general population, with the highest risk occurring in the early months following diagnosis and in those with advanced disease or severe symptom burden [15]. Bipolar disorder independently confers the highest suicide risk among psychiatric disorders, with lifetime suicidal ideation reported in up to 60% of patients, suicide attempts in at least 25%, and suicide completion in 15–19% of all patients with bipolar disorder [16]. Although the risk of suicide in people with both bipolar disorder and an oncological diagnosis has not been systematically studied, both illnesses place individuals at high risk, increasing the need for close screening and integration of psychiatric and oncologic care.

1.2. Medical and treatment-related causes of mood symptoms in cancer care

Several aspects of oncological conditions, including central nervous system involvement or inflammation and medication side effects, can contribute to mood symptoms, including depression or secondary mania. Secondary mania is defined as mania that occurs due to another medical illness, neurological disorder, or substance use in people without a prior history of bipolar disorder [17], [18]. Signs that point to a secondary cause of mania include a first manic episode after age 40; temporal onset of mania immediately after cancer diagnosis or treatment; and presence of neurological symptoms and signs [17], [18]. Secondary mania is etiologically distinct from primary bipolar disorder, and in addition to mood stabilizing agents, may require treatment directed at the underlying neurological or medical cause, or cessation of an inciting pharmacological agent.

1.3. Neurological conditions

Brain tumors, both primary and metastatic, may present with psychiatric symptoms, including depression, hypomania, mania, and psychosis. The prevalence of depression in brain tumors is estimated to be around 20%, with higher grade tumors conferring a higher risk [19]. Tumors involving the frontal or temporal regions, subcortical limbic structures, and pons are more likely to produce (hypo)mania symptoms, as are tumors located on the right side of the brain [17], [18], [20].

Autoimmune encephalitis (AIE) may also present with psychiatric symptoms, including mania, psychosis, and catatonia [21]. AIE generally has a subacute onset and may present with neurological symptoms, seizures, and/or vital sign instability [21], [22]. AIE can be paraneoplastic and is sometimes the presenting syndrome leading to a cancer diagnosis. Tumors associated with AIE include ovarian teratomas, thymoma, thyroid cancer, lung cancer, breast cancer, and renal cell cancers [22]. Immune checkpoint inhibitors, an intravenous treatment used for various cancers such as melanoma, bladder cancer, and Hodgkin lymphoma, may also rarely (incidence of <1%) cause an immune encephalitis [23].

When brain malignancy or AIE is suspected, brain imaging (preferably MRI with contrast) must be obtained. Criteria for diagnosing AIE include subacute onset of new CNS findings, new seizures, WBC in cerebrospinal fluid, or MRI findings suggestive of encephalitis, not explained by another known cause [24]. When AIE is suspected, serum and cerebrospinal fluid antibody testing should be performed, with the caveat that an estimated 50% of patients with AIE are seronegative [25].

1.4. Medications

1.4.1. Antineoplastics

Medications used to treat the underlying cancer, antineoplastics, may also induce or contribute to mood episodes. While overall depression rates in oncological patients are around 15% [26], confounding factors such as the stress of cancer itself, varying types of cancers and stages, and pre-existing mental illnesses, make it difficult to discern how much of a risk each individual chemotherapeutic agent confers. However, most categories of antineoplastics have been associated with an increased risk of developing depressive symptoms, including protein kinase inhibitors, anti-metabolites (e.g., methotrexate), androgen deprivation therapy, monoclonal antibodies, aromatase inhibitors, estrogen-receptor modulators, interferons, antibody-drug conjugates, plant alkaloids, tyrosine kinase inhibitors, and immune checkpoint inhibitors [17], [27], [28], [29]. In addition, interferon-alpha has also been associated with hypomania, mania, and mixed affective episodes [30]. Patients with a history of bipolar disorder undergoing treatment with antineoplastics require monitoring for recurrence of a mood episode and may need psychotropic medication adjustments if one occurs. If interferon-alpha is prescribed, close collaboration between oncology and psychiatry is warranted. Indeed, in the course of bipolar disorder, the occurrence of depression increases the risk of mania [31].

1.4.2. Steroids

Corticosteroids are commonly prescribed during cancer treatment and include prednisone, prednisolone, methylprednisolone, cortisone, and dexamethasone. Steroids can induce psychiatric side effects and mood episodes in both patients with and without pre-existing mental health conditions, with potential side effects including depression, hypomania and mania, psychosis, cognitive dysfunction, and delirium [32]. Risk factors for psychiatric side effects of steroids include pre-existing psychiatric disorders, older age, prolonged steroid therapy, intravenous administration, and high steroid dosage, although lower dosages and oral routes may also precipitate symptoms. While discontinuation may help improve or resolve symptoms, symptoms can persist for months after discontinuation and often require psychotropic treatment. People with a history of bipolar disorder should be on a mood stabilizing medication regimen prior to steroid initiation and monitored carefully throughout treatment, as exacerbations are common. In people without bipolar disorder but who have previously had severe side-effects provoked by steroids, such as mania or psychosis, a mood stabilizing agent may need to be preemptively considered prior to prescribing steroids.

2. Psychopharmacological considerations in cancer patients with bipolar disorder

Many medications used in the management of bipolar disorder have implications for oncological practice, both in terms of cancer patients’ potential increased susceptibility to adverse effects and the risk for drug-drug interactions between psychotropics and antineoplastics. Clinicians should consider the following side effect profiles before proceeding with the use of certain medications concurrently with cancer treatment.

2.1. Antipsychotics

Antipsychotics are associated with a variety of adverse effects, including but not limited to QTc prolongation, metabolic syndrome, agranulocytosis, and elevated seizure risk, although the level of risk conferred differs by each medication. In general, second-generation anti-psychotics (SGAs) tend to be favored for their lower side effect profiles and will be focused on in this review.

QTc prolongation is most common with ziprasidone, but is also of moderate risk with olanzapine, risperidone, and quetiapine [33], [34]. Cancer patients are at increased risk of a prolonged QTc, as many medications often used to manage chemotherapy-related nausea have QTc-prolonging effects, such as ondansetron, domperidone, metoclopramide, and certain first-generation H1 antagonists [35]. Baseline and interval EKG monitoring should be obtained in patients on multiple QTC-prolonging agents.

Risk of antipsychotic-induced agranulocytosis is compounded in cancer patients receiving immunosuppressant chemotherapy regimens. Of all antipsychotics, clozapine is associated with the highest risk (although absolute risk remains low around 1.5%), with quetiapine and risperidone posing this risk to lesser degrees [36]. A systematic review of patients receiving both clozapine and anti-cancer agents found that 64% developed neutropenia over the course of treatment, with 20% resulting in neutropenia-related infections [37]. Patients at increased risk of agranulocytosis, such as those on bone marrow suppressants, require closer monitoring.

Clozapine is also most implicated in the risk of seizures conferred by antipsychotics. Other SGAs have a much lower risk when administered alone, but seizures become more common when given concurrently with other medications such as tricyclic antidepressants and lithium [38]. Neuro-oncological patients are at heightened risk for seizures due to cancer-related structural brain changes. Practice guidelines recommend against prophylactic anti-seizure medications for neuro-oncological patients without prior seizures [39]. While clozapine lowers the seizure threshold, it is not strictly contraindicated in patients at elevated seizure risk, only in those with uncontrolled seizures, and therefore could still be utilized after careful consideration of risks and benefits and patient education about potential signs and symptoms of seizures. As clozapine is often reserved for treatment-resistant cases, addition of an antiepileptic may still be favored over discontinuation of clozapine.

Conversely, the metabolic side effects associated with SGAs may provide some benefit in the context of oncological care. Many cancer patients suffer from malnutrition and weight loss secondary to reduced food intake and altered metabolism. Olanzapine has been proposed to have a role in the treatment of cancer-related anorexia-cachexia syndrome due to its promotion of weight gain and appetite, and suppression of nausea and vomiting [34]. Olanzapine is also sedating and may help with sleep, which is often a problem in this population.

2.2. Mood stabilizers

Lithium, a first-line medication in the treatment of bipolar disorder and life-saving treatment for many with bipolar disorder, has a narrow therapeutic index, requiring careful monitoring. Lithium clearance takes place entirely via the kidneys, so patients with impaired renal function are at greater risk for toxicity. Conversely, antineoplastics that enhance renal clearance may lower levels and risk loss of efficacy [40]. Fortunately, lithium levels are easy to obtain and meaningfully guide treatment decisions.

Lithium is also associated with various adverse effects, with renal impairment and hypothyroidism being particularly relevant in oncological practice. Lithium’s renal side effects have a wide range of severity, from polyuria and mildly elevated creatinine to nephrogenic diabetes insipidus as well as chronic interstitial nephritis, which can progress to end-stage renal disease, although very rarely in the absence of pre-existing renal disease. Patients treated with lithium have been shown to exhibit significantly higher levels of kidney injury markers along with decreased eGFR[41]. Nephrotoxic agents are particularly insidious for cancer patients, who may already be exposed to anti-cancer therapies that are harmful to the kidneys, such as alkylating agents, platinum compounds, immune checkpoint inhibitors, and antimicrotubular drugs [42]. Indeed, many cancer patients exhibit renal insufficiency, with nearly 50% decreased GFR among patients with solid tumors, which correlated with a significantly decreased mean survival of 16.4 months compared to 25 months in those with normal renal function [43]. Renal insufficiency, regardless of etiology, has important implications for chemotherapeutic drug dosing, and cancer patients on potentially nephrotoxic agents such as lithium should be monitored for reduced GFR.

Second, hypothyroidism is a well-documented adverse effect associated with lithium, with patients on lithium therapy being found to have a six-fold increased risk of reduced thyroid function, for which routine monitoring is indicated at least once or twice annually [44]. Similarly to renal insufficiency, cancer patients are especially vulnerable to this effect due to the combined risk of hypothyroidism associated with certain anti-cancer therapies, including radiation to the head and neck. Risk of hypothyroidism can be as high as 30–50% following radiation therapy, and 25–70% in patients receiving tyrosine kinase inhibitors [45]; these patients may require more frequent monitoring.

Valproate is a known cause of hepatic injury [46]. Once more, the concern for hepatic damage becomes more concerning in cancer patients, who may already be subject to chemotherapy-induced hepatic injury [47]. This is further complicated by anti-cancer agents undergoing hepatic clearance, such as cisplatin, etoposide, and nitrosoureas, as valproic acid inhibits many CYP enzymes [40]. For these reasons, oncological patients receiving hepatotoxic drugs such as valproate should be assessed for hepatic insufficiency, and chemotherapy dose adjustment should be performed as necessary to prevent chemotherapy side effects and immunosuppression. A baseline valproic acid level should be obtained (before chemotherapy initiation), routinely during a chemotherapy cycle, and if signs or symptoms of toxicity appear. In addition, valproic acid may also cause thrombocytopenia, with a dose-related effect [48]. In patients undergoing types of chemotherapy that induce myelosuppression, this risk is compounded. Blood counts are obtained routinely during chemotherapy cycles, but this frequency may need to be increased for patients on valproic acid, or if counts begin to lower.

Carbamazepine and oxcarbazepine, both anticonvulsants also used as mood stabilizers, are CYP3A4 enzyme inducers with important considerations for hepatic drug clearance [40], [49], affecting the clearance of anti-cancer medications such as alkylating agents, mTOR inhibitors, and taxanes[50]. Most of these drugs experience increased clearance in the presence of the CYP3A4 inducers; however, pro-drugs may be more quickly converted to their active metabolites, thus resulting in increased plasma concentrations of the active medication. Oxcarbazepine is a weaker inducer, with carbamazepine showing a 46% higher effect in some studies [49]. However, oxcarbazepine’s use in treating bipolar disorder is not strongly supported by studies. Patients on these medications warrant a pharmacy consultation for discussion of drug-drug interactions, and may need dose adjustments.

Carbamazepine and oxcarbazepine are also associated with hyponatremia, with severe hyponatremia being more common in oxcarbazepine, requiring a baseline sodium level, levels after dose increases, and periodically throughout treatments [51]. Cancer patients are more sensitive to sodium derangements, with up to 40% of hospitalized oncological patients experiencing hyponatremia [52]. This is mainly a result of syndrome of inappropriate anti-diuretic hormone (SIADH), which is strongly linked as a paraneoplastic syndrome, particularly to small-cell lung cancer [52]. Patients at risk of hyponatremia, or with downtrending sodium levels, may require more close monitoring of electrolytes, and potentially medication discontinuation.

Finally, carbamazepine is associated with the development of idiosyncratic agranulocytosis. Similarly to clozapine-induced agranulocytosis, this risk is of particular concern in cancer patients concurrently on anti-cancer drug regimens with immunosuppressant effects, as carbamazepine-associated agranulocytosis is more common in those with lower leukocyte counts at baseline. However, the development of leukopenia while receiving carbamazepine is not a definitive indication for discontinuation; rather, patients should be monitored for symptoms of infection and carbamazepine should be withdrawn if leukocyte count falls below 3k. Carbamazepine is not strictly contraindicated in cancer patients already receiving immunosuppressive therapy, but close monitoring of leukocyte levels is necessary [53].

Lamotrigine is an antiepileptic medication and mood stabilizer that may be favored for concurrent treatment of bipolar disorder and brain tumor-related seizures due to lack of enzyme effects and subsequent minimal drug-drug interactions. Lamotrigine is, however, associated with some rare but severe adverse effects that are more common in immunocompromised patients, such as Stevens-Johnson Syndrome (SJS), Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS), and Hemophagocytic Lymphohistiocytosis (HLH) [54]. Cancer patients are at an increased risk for SJS, with an odds ratio of 2, primarily driven by those with hematological malignancy, as well as face increased mortality from SJS/TEN if it occurs [55]. Therefore, the use of lamotrigine in the oncological patient population should be done carefully, with patients who are prescribed lamotrigine receiving slow up-titration of the drug to minimize this risk along with detailed patient education on adverse effect recognition.

2.3. Management Across survivorship, remission, and end-of-life

Bipolar disorder psychotropic management must also be considered across the full trajectory of cancer. Bipolar disorder-specific guidance for cancer survivors is limited, but these individuals remain vulnerable to mood episode recurrence even following conclusion of cancer treatment, often precipitated by treatment-related sequelae, adjustment to post-treatment survivorship, and fear of recurrence [56].

In the setting of cancer remission, psychotropic regimens should be re-evaluated. Medications adjusted during active treatment may need to be optimized for long-term mood stability. For example, if a psychotropic medication was decreased due to anti-neoplastic interactions or side effects, this medication may need to be increased once anti-neoplastic agents are discontinued. Alternatively, a medication increased during a mood episode in the context of cancer may be able to be decreased back to pre-cancer dosages, dependent upon continued mood episode remission, patient tolerability, and patient preference.

Maintenance endocrine therapies for hormone receptor-positive breast cancer require additional psychopharmacological consideration. Tamoxifen depends partly on CYP2D6 metabolism to convert to active metabolites; strong CYP2D6 inhibitors such as fluoxetine, paroxetine, and bupropion should generally be avoided when there is an alternative option [57]. Aromatase inhibitors do not share this CYP2D6 activation issue, but may worsen insomnia, fatigue, arthralgias, vasomotor symptoms, and depressive symptoms [58]. The aromatase inhibitor exemestane is additionally vulnerable to CYP3A4 induction, making carbamazepine and other strong enzyme inducers potentially problematic [59].

In cases of poor cancer prognosis, continued psychiatric involvement can support quality of life, decision-making capacity, and meaningful participation in goals-of-care discussions. Psychiatric care should be integrated with oncology and palliative care to address mood symptoms, pain-related distress, delirium risk, steroid-induced mood symptoms, existential distress, and end-of-life goals. Treatment decisions regarding psychotropics should balance long-term mood stability with comfort, safety, and the patient’s goals and values. This is particularly important given that individuals with SMI are at risk for reduced access to palliative services and less goal-concordant end-of-life care [60]. Proactive palliative care referral, collaborative communication, caregiver involvement when appropriate, and careful capacity assessment may help promote equitable, goal-concordant care [60], [61].

3. Non-pharmacological considerations

Psychotherapy is a well-established treatment for bipolar disorder, with research supporting the combined efficacy of medication and psychotherapy compared to medication alone [62]. Psychotherapeutic modalities with benefit in bipolar disorder include cognitive-behavioral therapy (CBT), family therapy, and psychoeducation.

Additionally, receiving a cancer diagnosis poses a profound burden on patients’ quality of life and subsequent psychological wellbeing. CBT has been well-studied for its benefits in reducing symptoms of depression and anxiety in cancer patients, as well as improving overall quality of life [63]. In addition to CBT, numerous other therapy modalities have been proven effective at targeting various aspects of mental health in the oncological patient population, including meaning-centered therapy, mindfulness-based therapies, and supportive-expressive therapies [63]. The routine consideration of adding psychotherapy to the treatment regimen in these individuals is therefore highly recommended.

Psychotherapy may also be utilized in cancer survivors for the management of fear of cancer recurrence (FCR). FCR is theorized to affect around 70% of survivors and contributes significantly to psychological distress [64]. CBT is the most widely studied modality for FCR and has been proven effective in face-to-face settings [65]. Some studies also suggest a role for approaches such as mindfulness, and acceptance and commitment therapy [65]. However, there remains a lack of clinical guidelines regarding both the diagnosis of FCR, and the choice and design of psychotherapeutic interventions. Further investigation is required to comprehensively evaluate the long-term benefits of various treatment modalities, as well as develop structured recommendations for their delivery.

Sleep disturbance is a critical consideration in bipolar disorder and cancer, as it represents a symptom and cause of both mania and depression [1] and is often associated with cancer and treatment. Circadian rhythm disturbance is a hallmark of bipolar disorder. Sleep pattern dysfunction is defined in the DSM−5 diagnostic criteria for bipolar disorder, with manic episodes classified as exhibiting decreased need for sleep, and depressive episodes noted to exhibit changes in sleep that could present as either insomnia or hypersomnia [1]. The relationship between sleep disturbance and mood symptoms is bidirectional; in addition to mania and depression resulting in changes in sleep, poor sleep quality or decreased hours of sleep can also serve as a potent trigger for the onset of mood symptoms [66]; sleep disturbance can be used to predict recurrence of mood episodes in bipolar disorder [67]. Sleep maintenance in patients with bipolar disorder is vitally important.

Hospitalized patients are at increased risk for sleep disruption due to a variety of factors, with some studies suggesting that patients on higher-acuity units experience the greatest disturbance [68]. Hospitalized cancer patients receiving ICU-level care are subject to frequent nighttime awakenings for lab work, vitals measurement, and overall physical discomfort. Cancer patients with comorbid psychiatric illness experience combined psychological disturbance of sleep quality, which in turn predisposes them to further mood symptoms. As such, sleep disturbance in these patient populations should be lessened wherever possible in the hospital setting. Strategies should focus on clustering blood draws, vitals, and other nursing activities during daytime hours, as well as prioritizing sleep hygiene through established nighttime routines and controlled environmental light and sound. If such modifications fail, pharmacologic treatment of insomnia is strongly indicated in bipolar disorder.

4. Conclusions

People with bipolar disorder have higher rates of morbidity and mortality from cancer and additionally are at increased risk of mood disturbances from treatment. Furthermore, their mood-stabilizing medications can interact with, and compound, side effects faced from their cancer treatment. Psychiatrists treating this population should be aware of these risk and be prepared to increase their therapeutic drug monitoring and surveillance. Routine prescribing of evidence-based psychotherapy is recommended. Future work should focus on integrating bipolar-specific screening and management strategies into psycho-oncology to improve outcomes.

Funding

This work was supported by the Mary O'Daniel Stone and Bill Stone Psychiatry Fund.

Declaration of Competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.