12.4 Psychiatric & Psychosocial Comorbidities in Cancer Care
Key Takeaways
- Depression affects roughly one in six patients with cancer and is diagnosed by the psychological symptoms of anhedonia, worthlessness, and hopelessness rather than by somatic symptoms that overlap with the disease.
- A PHQ-9 score of 10 or higher indicates at least moderate depression, and a GAD-7 score of 10 or higher indicates at least moderate anxiety.
- Delirium is the most common neuropsychiatric complication of advanced cancer, and hypoactive delirium is frequently misdiagnosed as depression; the Confusion Assessment Method identifies it by acute onset with fluctuation plus inattention.
- Delirium management begins with identifying and reversing the cause, with antipsychotics reserved for distressing agitation and benzodiazepines avoided except in alcohol or sedative withdrawal and in terminal refractory agitation.
- Fluoxetine, paroxetine, and bupropion are strong CYP2D6 inhibitors that reduce conversion of tamoxifen to endoxifen, so venlafaxine, citalopram, or escitalopram are preferred in patients taking tamoxifen.
12.4 Psychiatric & Psychosocial Comorbidities in Cancer Care
Blueprint focus: ONCC Domain IV.D — Psychiatric and psychosocial comorbidities, including anxiety, depression, and cognitive impairment. These conditions worsen adherence, amplify symptom burden, prolong hospitalization, and independently worsen survival.
Depression
Prevalence. Roughly one in six patients with cancer meets criteria for major depression — far above the general population — and rates are highest in pancreatic, head and neck, and lung cancer and in advanced disease.
The diagnostic problem. The somatic criteria for depression — fatigue, appetite loss, weight change, sleep disruption, psychomotor slowing — are also produced by cancer and its treatment. Relying on them over-diagnoses depression in physically ill patients. Weight the psychological criteria instead:
- Pervasive anhedonia — loss of pleasure in everything, not just in activities the illness has made impossible
- Worthlessness and excessive guilt
- Hopelessness that is global, extending beyond the medical prognosis
- Suicidal ideation
Screening. The PHQ-9 with a cutoff of 10 or higher for at least moderate depression; the PHQ-2 as an ultra-brief screen; the Hospital Anxiety and Depression Scale (HADS), designed to minimize somatic items and therefore well suited to medically ill populations.
Rule out organic contributors before diagnosing: hypothyroidism, hypercalcemia, anemia, B12 deficiency, brain metastases, corticosteroids, interferon, opioid oversedation, and uncontrolled pain — which alone can produce a depression-like picture that resolves entirely with adequate analgesia.
Treatment. Combine psychotherapy — cognitive behavioral therapy, behavioral activation, meaning-centered or supportive-expressive therapy — with pharmacotherapy for moderate to severe depression, and add exercise, which has independent antidepressant effect. Expect a 4- to 6-week latency to antidepressant response, which matters when prognosis is short; methylphenidate works within days and is used for depressive symptoms in advanced disease with limited life expectancy.
Antidepressant selection in oncology
| Situation | Preferred | Avoid and why |
|---|---|---|
| On tamoxifen | Venlafaxine, citalopram, escitalopram | Fluoxetine, paroxetine, bupropion — strong CYP2D6 inhibitors that reduce conversion of tamoxifen to its active metabolite endoxifen |
| Hot flashes plus depression | Venlafaxine, desvenlafaxine | — |
| Neuropathic pain plus depression | Duloxetine (also first-line for painful CIPN) | — |
| Insomnia and poor appetite | Mirtazapine (sedating, appetite-stimulating, antiemetic at low dose) | — |
| Fatigue with low motivation | Bupropion (if not on tamoxifen) | Caution with seizure risk and brain metastases |
| On multiple QT-prolonging agents | Sertraline (lower QT effect) | Citalopram at higher doses |
| On tramadol, linezolid, or triptans | Any SSRI/SNRI with counseling | Watch for serotonin syndrome |
Anxiety
Presentation. Anxiety in cancer clusters around specific triggers — the diagnostic wait, scans, procedures, treatment initiation, transitions of care, and disease progression — rather than being continuous.
Screening. GAD-7, with a score of 10 or higher indicating at least moderate anxiety.
Rule out organic causes that mimic anxiety: hypoxia, pulmonary embolism, pain, uncontrolled nausea, hypoglycemia, corticosteroids, akathisia from antiemetics such as metoclopramide and prochlorperazine, thyrotoxicosis, and withdrawal from alcohol, benzodiazepines, or opioids. A patient who is suddenly anxious and dyspneic needs a pulmonary embolism ruled out before a benzodiazepine.
Treatment. Cognitive behavioral therapy, relaxation training, mindfulness, and hypnosis for procedural anxiety; SSRIs or SNRIs for persistent anxiety; short-acting benzodiazepines such as lorazepam for situational anxiety, procedures, and anticipatory nausea, used cautiously in older adults and in anyone with delirium risk.
Delirium
Delirium is the most common neuropsychiatric complication of advanced cancer, affecting the large majority of patients in the final weeks of life. It is frequently missed, and hypoactive delirium is routinely misdiagnosed as depression.
Confusion Assessment Method (CAM) requires:
- Acute onset and fluctuating course, and
- Inattention, plus either
- Disorganized thinking, or
- Altered level of consciousness.
| Feature | Depression | Hypoactive delirium |
|---|---|---|
| Onset | Weeks | Hours to days |
| Course | Steady | Fluctuating, worse at night |
| Attention | Usually intact | Impaired — the cardinal feature |
| Consciousness | Clear | Clouded |
| Orientation | Intact | Impaired |
| Reversibility | Slow | Often reversible if the cause is found |
Common reversible causes: medications (opioids, benzodiazepines, anticholinergics, corticosteroids), infection, hypercalcemia, hyponatremia, hypoxia, dehydration, renal or hepatic failure, brain metastases, urinary retention, constipation, uncontrolled pain, and withdrawal.
Management.
- Find and treat the cause — this is the definitive intervention.
- Nonpharmacologic first: reorientation, familiar objects and family presence, glasses and hearing aids, daylight exposure and a dark quiet night, mobilization, hydration, sleep protection, and avoiding restraints, which worsen agitation.
- Antipsychotics — haloperidol, olanzapine, quetiapine, or risperidone — are reserved for distressing agitation or dangerous behavior, not for quiet hypoactive delirium.
- Avoid benzodiazepines, which worsen delirium, except in alcohol or sedative-hypnotic withdrawal and in refractory terminal agitation.
Cancer-Related Cognitive Impairment
Affecting roughly 20% to 30% of survivors after chemotherapy, this involves deficits in working memory, processing speed, executive function, and word finding. Contributors include chemotherapy, cranial radiation, endocrine therapy, anemia, fatigue, sleep disruption, depression, anxiety, and polypharmacy.
Management: validate the experience, treat the reversible contributors, refer for neuropsychological assessment when deficits are functionally significant, and provide cognitive rehabilitation, compensatory strategies (calendars, lists, single-tasking, reduced distraction), exercise, and mindfulness. No pharmacologic agent has consistent evidence.
Substance Use Disorder and Serious Mental Illness
- Substance use disorder coexists with cancer more often than is documented. Cancer pain still requires treatment; the approach is structure and co-management, as described in Section 9.2, not withholding analgesia. Screen for alcohol and benzodiazepine dependence before hospitalization, since unrecognized withdrawal presents as agitated delirium on day 2 to 3.
- Serious mental illness — schizophrenia, bipolar disorder, severe major depression — is associated with later stage at diagnosis, lower rates of guideline-concordant treatment, and worse cancer survival. Involve psychiatry early, coordinate psychotropic monitoring (clozapine and agranulocytosis interacting with myelosuppressive chemotherapy; lithium and renal or fluid shifts), and never let a psychiatric diagnosis become the reason a patient is offered less cancer treatment.
Suicide Risk
Patients with cancer carry an elevated suicide risk relative to the general population, highest in the first months after diagnosis and in head and neck, lung, pancreatic, and esophageal cancers, and in male and older patients.
Ask directly — asking about suicide does not create the idea. Any positive response requires an immediate risk assessment: ideation, plan, means, intent, and protective factors. For a patient with a plan and intent, initiate safety protocols, do not leave the patient alone, remove access to lethal means including stockpiled opioids, and arrange emergency psychiatric evaluation. Also distinguish suicidal intent from a desire for hastened death arising from uncontrolled symptoms or loss of dignity — that finding calls for aggressive palliative care, which frequently resolves it.
A 78-year-old man with metastatic prostate cancer becomes withdrawn, quiet, and minimally responsive over 2 days. He is oriented to person only, cannot recite the months backward, and is more confused each evening. His nurse reports he 'seems depressed.' What is the most likely diagnosis?
A 49-year-old premenopausal woman taking adjuvant tamoxifen develops moderate depression with a PHQ-9 score of 16. Which antidepressant should be avoided, and why?
A patient with newly diagnosed pancreatic cancer says at his second visit, 'Sometimes I think everyone would be better off if I just didn't wake up.' What should the nurse practitioner do first?