Psycho-oncology: depression, interactions, delirium, and capacity (MEQ)

(i) Differential. Working diagnosis for the 5-week syndrome: major depressive episode in the context of cancer (pervasive anhedonia, insomnia with early waking, passive death wishes, PHQ-9 18) rather than simple normative sadness.[8] Consider coexisting demoralisation (pointlessness/subjective incompetence) which may amplify distress and guide meaning-centred therapy, but does not exclude MDD.[5] Intermittent steroid neuropsychiatric effects (insomnia/irritability after dexamethasone escalations) are a parallel process and can worsen mood, sleep, and judgement.[4] Night-time IV-pulling with confusion suggests delirium until proven otherwise (acute change, behavioural disturbance) — apply CAM reasoning and medical work-up; do not collapse everything into one label.[7]

(ii) Depression care and tamoxifen-safe pharmacology. Offer integrated collaborative care modelled on SMaRT Oncology-2: systematic identification, care management, psychiatrist supervision, measurement-based antidepressant treatment, and psychological strategies — this improves depression outcomes versus usual care.[1] Do not "start any SSRI." Avoid strong CYP2D6 inhibitors such as paroxetine and fluoxetine with tamoxifen (Kelly mortality signal).[2] Prefer agents with more favourable interaction profiles when clinically suitable, e.g. sertraline 25–50 mg oral daily titrating toward response (often 50–150 mg), escitalopram 5–10 mg, or mirtazapine 7.5–15 mg at night if sleep/appetite are priorities — monitor hyponatraemia, nausea overlap, QTc where relevant, and suicide risk early after starting.[2][8] Address pain, sleep, and practical supports; involve psychology. Screen actively for escalating suicidal ideation (elevated risk after cancer diagnosis in Fang data).[6]

(iii) Night confusion / antipsychotics. Treat as delirium: reverse precipitants (infection, metabolic, CNS disease, opioids, steroids, constipation/retention), non-drug measures first. Agar 2017: risperidone and haloperidol produced worse delirium symptom scores than placebo in palliative care with more EPS — do not prescribe scheduled neuroleptics as default "confusion treatment." Reserve low-dose short-term antipsychotic only for severe distress or danger after non-drug care, with daily review.[3][7]

(iv) Capacity. Capacity is decision-specific. Chemotherapy refusal requires understanding of nature, benefits, risks, and alternatives, retention, weighing, and communication. Severe depression with hopelessness, steroid-related irritability/possible mania, or delirium can each impair weighing and understanding. Document assessment, treat reversible factors (delirium, steroid toxicity, depression), reassess, involve substitute decision-makers under local law if incapacitous, and avoid processing major refusals solely on a single "no" during an acute confusional or highly distorted affective state.[4][7][8]