The prevalence and effects of delirium in very old individuals aged ≥80 years have not yet been systematically evaluated. Therefore, this large single-center study of the one-year prevalence of delirium in 3,076 patients in 27 medical departments of the University Hospital of Zurich was conducted.

Patient scores on the Delirium Observation Screening scale, Intensive Care Delirium Screening Checklist, Diagnostic and Statistical Manual, 5th edition, and electronic Patient Assessment–Acute Care (nursing tool) resulted in the inclusion of 3,076 individuals in 27 departments. The prevalence rates were determined by simple logistic regressions, odds ratios (ORs), and confidence intervals.

Of the 3,076 patients, 1,285 (41.8%) developed delirium. The prevalence rates in the 27 departments ranged from 15% in rheumatology (OR = 0.30) to 73% in intensive care (OR = 5.25). Delirious patients were more likely to have been admitted from long-term care facilities (OR = 2.26) or because of emergencies (OR = 2.24). The length of their hospital stay was twice as long as that for other patients. Some died before discharge (OR = 24.88), and others were discharged to nursing homes (OR = 2.96) or assisted living facilities (OR = 2.2).

This is the largest study to date regarding the prevalence of delirium in patients aged ≥80 years and the medical characteristics of these patients. Almost two out of five patients developed delirium, with a high risk of loss of independence and mortality.

Delirium is a frequent complication in advanced cancer patients, among whom it is frequently underdiagnosed and inadequately treated. To date, evidence on risk factors and the prognostic impact of delirium on outcomes remains sparse in this patient population.

In this prospective observational cohort study at a single tertiary-care center, 1,350 cancer patients were enrolled. Simple and multiple logistic regression models were utilized to identify associations between predisposing and precipitating factors and delirium. Cox proportional-hazards models were used to estimate the effect of delirium on death rate.

In our patient cohort, the prevalence of delirium was 34.3%. Delirium was associated inter alia with prolonged hospitalization, a doubling of care requirements, increased healthcare costs, increased need for institutionalization (OR 3.22), and increased mortality (OR 8.78). Predisposing factors for delirium were impaired activity (OR 10.82), frailty (OR 4.75); hearing (OR 2.23) and visual impairment (OR 1.89), chronic pneumonitis (OR 2.62), hypertension (OR 1.46), and renal insufficiency (OR 1.82). Precipitating factors were acute renal failure (OR 7.50), pressure sores (OR 3.78), pain (OR 2.86), and cystitis (OR 1.32). On multivariate Cox regression, delirium increased the mortality risk sixfold (HR 5.66). Age ≥ 65 years and comorbidities further doubled the mortality risk of delirious patients (HR 1.77; HR 2.05).

Delirium is common in cancer patients and associated with increased morbidity and mortality. Systematically categorizing predisposing and precipitating factors might yield new strategies for preventing and managing delirium in cancer patients.

Although age and pre-existent dementia are robust risk factors for developing delirium, evidence for patients older than 90 years is lacking. Therefore, this study assesses the delirium prevalence rates and sequelae in this age group.

Based on a Diagnostic and Statistical Manual (DSM)-5, Delirium Observation screening scale (DOS), and Intensive Care Delirium Screening Checklist (ICDSC) construct, in this prospective cohort study, the prevalence rates and sequelae of delirium were determined in 428 patients older than 90 years by simple logistic regressions and corresponding odds ratios (ORs).

The overall prevalence delirium rate was 45.2%, with a wide range depending upon specialty: intermediate and intensive care services (83.1%), plastic surgery and palliative care (75%), neurology (72%), internal medicine (69%) vs. dermatology (26.5%), and angiology (14.5%). Delirium occurred irrespective of age and gender; however, pre-existent dementia was the strongest delirium predictor (OR 36.05). Delirious patients were less commonly admitted from home (OR 0.47) than from assisted living (OR 2.24), indicating functional impairment. These patients were more severely ill, as indicated by emergency (OR 3.25) vs. elective admission (OR 0.3), requirement for intensive care management (OR 2.12) and ventilation (OR 5.56–8.33). At discharge, one-third did not return home (OR 0.22) and almost half were transferred to assisted living (OR 2.63), or deceased (OR 47.76).

At age older than 90 years, the prevalence and sequelae of delirium are substantial. In particular, functional impairment and pre-existent dementia predicted delirium and subsequently, the loss of independence and death were imminent.

Patients with terminal illness are at high risk of developing delirium, in particular, those with multiple predisposing and precipitating risk factors. Delirium in palliative care is largely under-researched, and few studies have systematically assessed key aspects of delirium in elderly, palliative-care patients.

In this prospective, observational cohort study at a tertiary care center, 229 delirious palliative-care patients stratified by age: <65 (N = 105) and ≥65 years (N = 124), were analyzed with logistic regression models to identify associations with respect to predisposing and precipitating factors.

In 88% of the patients, the underlying diagnosis was cancer. Mortality rate and median time to death did not differ significantly between the two age groups. No inter-group differences were detected with respect to gender, care requirements, length of hospital stay, or medical costs. In patients ≥65 years, exclusively predisposing factors were relevant for delirium, including hearing impairment [odds ratio (OR) 3.64; confidence interval (CI) 1.90–6.99; P < 0.001], hypertension (OR 3.57; CI 1.84–6.92; P < 0.001), and chronic kidney disease (OR 4.84; CI 1.19–19.72; P = 0.028). In contrast, in patients <65 years, only precipitating factors were relevant for delirium, including cerebral edema (OR 0.02; CI 0.01–0.43; P = 0.012).

The results of this study demonstrate that death in delirious palliative-care patients occurs irrespective of age. The multifactorial nature and adverse outcomes of delirium across all age in these patients require clinical recognition. Potentially reversible factors should be detected early to prevent or mitigate delirium and its poor survival outcomes.

The general in-hospital mortality and interrelationship with delirium are vastly understudied. Therefore, this study aimed to assess the rates of in-hospital mortality and terminal delirium.

In this prospective cohort study of 28,860 patients from 37 services including 718 in-hospital deaths, mortality rates and prevalence of terminal delirium were determined with simple logistic regressions and their respective odds ratios (ORs).

Although overall in-hospital mortality was low (2.5%), substantial variance between services became apparent: Across intensive care services the rate was 10.8% with a 5.8-fold increased risk, across medical services rates were 4.4% and 2.4-fold, whereas at the opposite end, across surgical services rates were 0.7% and 87% reduction, respectively. The highest in-hospital mortality rate occurred on the palliative care services (27.3%, OR 19.45). The general prevalence of terminal delirium was 90.7% and ranged from 83.2% to 100%. Only across intensive care services (98.1%, OR 7.48), specifically medical intensive care (98.1%, OR 7.48) and regular medical services (95.8%, OR 4.12) rates of terminal delirium were increased. In contrast, across medical services (86.4%, OR 0.32) and in particular oncology (73.9%, OR 0.25), pulmonology (72%, OR 0.31) and cardiology (63.2%, OR 0.4) rates were decreased. For the remaining services, rates of terminal delirium were the same.

Although in-hospital mortality was low, the interrelationship with delirium was vast: most patients were delirious at the end of life. The implications of terminal delirium merit further studies.

The prevalence rates and adversities of delirium have not yet been systematically evaluated and are based on selected populations, limited sample sizes, and pooled studies. Therefore, this study assesses the prevalence rates and outcome of and odds ratios for managing services for delirium.

In this prospective cohort study, based on the Diagnostic and Statistical Manual (DSM) 5, the Delirium Observation Screening (DOS) scale, and the Intensive Care Delirium Screening Checklist (ICDSC) construct, 28,118 patients from 35 managing services were included, and the prevalence rates and adverse outcomes were determined by simple logistic regressions and their corresponding odds ratios (ORs).

Delirious patients were older, admitted from institutions (OR 3.44–5.2), admitted as emergencies (OR 1.87), hospitalized twice longer, and discharged, transferred to institutions (OR 5.47–6.6) rather than home (OR 0.1), or deceased (OR 43.88). The rate of undiagnosed delirium was 84.2%. The highest prevalence rates were recorded in the intensive care units (47.1–84.2%, pooled 67.9%); in the majority of medical services, rates ranged from 20% to 40% (pooled 26.2%), except, at both ends, palliative care (55.9%), endocrinology (8%), and rheumatology (4.4%). Conversely, in surgery and its related services, prevalence rates were lower (pooled 13.1%), except for cardio- and neurosurgical services (53.3% and 46.4%); the lowest prevalence rate was recorded in obstetrics (2%).

Delirium remains underdiagnosed, and novel screening approaches are required. Furthermore, this study identified the impact of delirium on patients, determined the prevalence rates for 32 services, and elucidated the association between individual services and delirium.

Nursing instruments have the potential for daily screening of delirium; however, they have not yet been evaluated. Therefore, after assessing the functional domains of the electronic Patient Assessment — Acute Care (ePA-AC), this study evaluates the cognitive and associated domains.

In this prospective cohort study in the intensive care unit, 277 patients were assessed and 118 patients were delirious. The impacts of delirium on the cognitive domains, consciousness and cognition, communication and interaction, in addition to respiration, pain, and wounds were determined with simple logistic regressions and their respective odds ratios (ORs).

Delirium was associated with substantial impairment throughout the evaluated domains. Delirious patients were somnolent (OR 6), their orientation (OR 8.2–10.6) and ability to acquire knowledge (OR 5.5–11.6) were substantially impaired, they lost the competence to manage daily routines (OR 8.2–22.4), and their attention was compromised (OR 12.8). In addition, these patients received psychotropics (OR 3.8), were visually impaired (OR 1.8), unable to communicate their needs (OR 5.6–7.6), displayed reduced self-initiated activities (OR 6.5–6.9) and challenging behaviors (OR 6.2), as well as sleep–wake disturbances (OR 2.2–5), Furthermore, delirium was associated with mechanical ventilation, abdominal/thoracic injuries or operations (OR 4.2–4.4), and sensory perception impairment (OR 3.9–5.8).

Delirium caused substantial impairment in cognitive and associated domains. In addition to the previously described functional impairments, these findings will aid the implementation of nursing instruments in delirium screening.

From case reports, haloperidol administration has been associated with QTc prolongation, torsades de pointes, and sudden cardiac death. In a vulnerable population of critically ill patients after cardiac surgery, however, it is unclear whether haloperidol administration affects the QTc interval. Thus, the aim of this study is to explore the effect of haloperidol in low doses on this interval.

This retrospective cohort study was performed on a cardio-surgical intensive care unit (ICU), screened 2,216 patients and eventually included 68 patients with delirium managed with oral and intravenous haloperidol. In this retrospective analysis, electrocardiograms were taken prior and within 24 h after haloperidol administration. The effect of haloperidol on QTc was determined with a Person correlation, and inter-group differences were measured with new long QT comparisons.

In total, 68 patients were included, the median age was 71 (64–79) years and predominantly male (77%). Haloperidol administration followed ICU admission by three days and the cumulative dose was 4 (2–9) mg. As a result, haloperidol administration did not affect the QTc (r = 0.144, p = 0.23). In total, 31% (21/68 patients) had a long QT before and 27.9% (19/68 patients) after haloperidol administration. Only 12% (8/68 patients) developed a newly onset long QT. These patients were not different in the route of administration, cumulative haloperidol doses, comorbidities, laboratory findings, or medications.

These results indicated that low-dose intravenous haloperidol was safe and not clinically relevant for the development of a newly onset long QT syndrome or adverse outcomes and support recent findings inside and outside the ICU setting.

Nursing assessments have been recommended for the daily screening for delirium; however, the utility of individual items have not yet been tested. In a first step in establishing the potential of the electronic Patient Assessment-Acute Care (ePA-AC) as such, the impact of delirium on the functional domains was assessed.

In this prospective observational cohort study, 277 patients were assessed and 118 patients were delirious. The impact of delirium on functional domains of the ePA-AC related to self-initiated activity, nutrition, and elimination was determined with simple logistic regressions.

Patients with delirium were older, sicker, were more commonly sedated during the assessment, stayed longer in the intensive care unit (ICU) and floors, and less commonly discharged home. A general pattern was the loss of abilities and full functioning equivalent to global impairment. For self-initiated mobility, in and out of the bed sizable limitations were noted and substantial inability to transfer caused friction and shearing. Similarly, any exhaustion and fatigue were associated with delirium. For self-initiated grooming and dressing, the impairment was greater in the upper body. Within the nutritional domain, delirium affected self-initiated eating and drinking, the amount of food and fluids, energy and nutrient, as well as parenteral nutrition requirement. In delirious patients, the fluid demand was rather increased than decreased, tube feeding more often required and dysphagia occurred. For the elimination domain, urination was not affected — of note, most patients were catheterized, whereas abilities to initiate or control defecation were affected.

Delirium was associated with sizable impairment in the level of functioning. These impairments could guide supportive interventions for delirious patients and perspectively implement nursing instruments for delirium screening.

Delirium is a common complication in palliative care patients, especially in the terminal phase of the illness. To date, evidence regarding risk factors and prognostic outcomes of delirium in this vulnerable population remains sparse.

In this prospective observational cohort study at a tertiary care center, 410 palliative care patients were included. Simple and multiple logistic regression models were used to identify associations between predisposing and precipitating factors and delirium in palliative care patients.

The prevalence of delirium in this palliative care cohort was 55.9% and reached 93% in the terminally ill. Delirium was associated with prolonged hospitalization (p < 0.001), increased care requirements (p < 0.001) and health care costs (p < 0.001), requirement for institutionalization (OR 0.11; CI 0.069–0.171; p < 0.001), and increased mortality (OR 18.29; CI 8.918–37.530; p < 0.001). Predisposing factors for delirium were male gender (OR 2.19; CI 1.251–3.841; p < 0.01), frailty (OR 15.28; CI 5.885–39.665; p < 0.001), hearing (OR 3.52; CI 1.721–7.210; p < 0.001), visual impairment (OR 3.15; CI 1.765–5.607; p < 0.001), and neoplastic brain disease (OR 3.63; CI 1.033–12.771; p < 0.05). Precipitating factors for delirium were acute renal failure (OR 6.79; CI 1.062–43.405; p < 0.05) and pressure sores (OR 3.66; CI 1.102–12.149; p < 0.05).

Our study identified several predisposing and precipitating risk factors for delirium in palliative care patients, some of which can be targeted early and modified to reduce symptom burden.

In the intensive care setting, delirium is a common occurrence; however, the impact of the level of alertness has never been evaluated. Therefore, this study aimed to assess the delirium characteristics in the drowsy, as well as the alert and calm patient.

In this prospective cohort study, 225 intensive care patients with Richmond Agitation and Sedation Scale (RASS) scores of −1 — drowsy and 0 — alert and calm were evaluated with the Delirium Rating Scale-Revised-1998 (DRS-R-98) and the Diagnostic and Statistical Manual 4th edition text revision (DSM-IV-TR)-determined diagnosis of delirium.

In total, 85 drowsy and 140 alert and calm patients were included. Crucial items for the correct identification of delirium were sleep–wake cycle disturbances, language abnormalities, thought process alterations, psychomotor retardation, disorientation, inattention, short- and long-term memory, as well as visuo-spatial impairment, and the temporal onset. Conversely, perceptual disturbances, delusions, affective lability, psychomotor agitation, or fluctuations were items, which identified delirium less correctly. Further, the severities of inattentiveness and visuo-spatial impairment were indicative of delirium in both alert- or calmness and drowsiness.

The impairment in the cognitive domain, psychomotor retardation, and sleep–wake cycle disturbances correctly identified delirium irrespective of the level alertness. Further, inattentiveness and — to a lesser degree — visuo-spatial impairment could represent a specific marker for delirium in the intensive care setting meriting further evaluation.

The hypoactive, hyperactive, and mixed subtypes of delirium differently impact patient management and prognosis, yet the evidence remains sparse. Therefore, we examined the outcome of varying management strategies in the subtypes of delirium.

In this observational cohort study, 602 patients were managed for delirium over 20 days with the following strategies: supportive care alone or in combination with psychotropics, single, dual, or triple+ psychotropic regimens. Cox regression models were calculated for time to remission and benefit rates (BRs) of management strategies.

Generally, the mixed subtype of delirium caused more severe and persistent delirium, and the hypoactive subtype was more persistent than the hyperactive subtype. The subtypes of delirium were similarly predictive for mortality (P = 0.697) and transfer to inpatient psychiatric care (P = 0.320). In the mixed subtype, overall, psychotropic drugs were administered more often (P = 0.016), and particularly triple+ regimens were administered more commonly compared to hypoactive delirium (P = 0.007). Patients on supportive care benefited most, whereas those on triple+ regimens did worst in terms of remission in all groups of hypoactive, hyperactive, and mixed subtypes (BR: 4.59, CI 2.01–10.48; BR: 4.59, CI 1.76–31.66; BR: 3.36, CI 1.73–6.52; all P < 0.05).

The mixed subtype was more persistent to management than the hypoactive and hyperactive subtypes. Delirium management remains controversial and, generally, supportive care benefited patients most. Psychopharmacological management for delirium requires careful choosing of and limiting the number of psychotropics.

The importance of the proper identification of delirium, with its high incidence and adversities in the intensive care setting, has been widely recognized. One common screening instrument is the Intensive Care Delirium Screening Checklist (ICDSC); however, the symptom profile and key features of delirium dependent on the level of sedation have not yet been evaluated.

In this prospective cohort study, the ICDSC was evaluated versus the Diagnostic and Statistical Manual, 4th edition, text revision, diagnosis of delirium set as standard with respect to the symptom profile, and correct identification of delirium. The aim of this study was to identify key features of delirium in the intensive care setting dependent on the Richmond Agitation and Sedation Scale levels of sedation: drowsiness versus alert and calmness.

The 88 delirious patients of 225 were older, had more severe disease, and prolonged hospitalization. Irrespective of the level of sedation, delirium was correctly classified by items related to inattention, disorientation, psychomotor alterations, inappropriate speech or mood, and symptom fluctuation. In the drowsy patients, inattention reached substantial sensitivity and specificity, whereas psychomotor alterations and sleep-wake cycle disturbances were sensitive lacked specificity. The positive prediction was substantial across items, whereas the negative prediction was only moderate. In the alert and calm patient, the sensitivities were substantial for psychomotor alterations, sleep-wake cycle disturbances, and symptom fluctuations; however, these fluctuations were not specific. The positive prediction was moderate and the negative prediction substantial. Between the nondelirious drowsy and alert, the symptom profile was similar; however, drowsiness was associated with alterations in consciousness.

In the clinical routine, irrespective of the level of sedation, delirium was characterized by the ICDSC items for inattention, disorientation, psychomotor alterations, inappropriate speech or mood and symptom fluctuation. Further, drowsiness caused altered levels of consciousness.

Similar to delirium, its subsyndromal form has been recognized as the cause of diverse adverse outcomes. Nonetheless, the nature of this subsyndromal delirium remains vastly understudied. Therefore, in the following, we evaluate the phenomenological characteristics of this syndrome versus no and full-syndromal delirium.

In this prospective cohort study, we evaluated the Delirium Rating Scale–Revised, 1998 (DRS–R–98) versus the Diagnostic and Statistical Manual of Mental Disorders, 4th ed., Text Revision (DSM–IV–TR) diagnostic criteria and examined the diagnosis of delirium with respect to phenomenological distinctions in the intensive care setting.

Out of 289 patients, 36 with subsyndromal delirium versus 86 with full-syndromal and 167 without delirium were identified. Agreement with respect to the DSM–IV–TR diagnosis of delirium was perfect. The most common subtype in those with subsyndromal delirium was hypoactive, in contrast to mixed subtype in those with full-syndromal delirium versus no motor alterations in those without delirium. By presence and severity of delirium symptoms, subsyndromal delirium was intermediate. The ability of the DRS–R–98 items to discriminate between either form of delirium was substantial. Between subsyndromal and no delirium, the cognitive domain and sleep–wake cycle were more impaired and allowed a distinction with no delirium. Further, between full- and subsyndromal delirium, the prevalence and severity of individual DRS–R–98 items were greater. Although the differences between these two forms of delirium was substantial, the items were not very specific, indicating that the phenomenology of subsyndromal delirium is closer to full-syndromal delirium.

Phenomenologically, subsyndromal delirium was found to be distinct from and intermediate between no delirium and full-syndromal delirium. Moreover, the greater proximity to full-syndromal delirium indicated that subsyndromal delirium represents an identifiable subform of full-syndromal delirium.

In the intensive care setting, delirium is a common occurrence that comes with subsequent adversities. Therefore, several instruments have been developed to screen for and detect delirium. Their validity and psychometric properties, however, remain controversial.

In this prospective cohort study, the Confusion Assessment Method for the Intensive Care Unit (CAM–ICU) and the Intensive Care Delirium Screening Checklist (ICDSC) were evaluated versus the DSM–IV–TR in the diagnosis of delirium with respect to their validity and psychometric properties.

Out of some 289 patients, 210 with matching CAM–ICU, ICDSC, and DSM–IV–TR diagnoses were included. Between the scales, the prevalence of delirium ranged from 23.3% with the CAM–ICU, to 30.5% with the ICDSC, to 43.8% with the DSM–IV–TR criteria. The CAM–ICU showed only moderate concurrent validity (Cohen's κ = 0.44) and sensitivity (50%), but high specificity (95%). The ICDSC also reached moderate agreement (Cohen's κ = 0.60) and sensitivity (63%) while being very specific (95%). Between the CAM–ICU and the ICDSC, the concurrent validity was again only moderate (Cohen's κ = 0.56); however, the ICDSC yielded higher sensitivity and specificity (78 and 83%, respectively).

In the daily clinical routine, neither the CAM–ICU nor the ICDSC, common tools used in screening and detecting delirium in the intensive care setting, reached sufficient concurrent validity; nor did they outperform the DSM–IV–TR diagnostic criteria with respect to sensitivity or positive prediction, but they were very specific. Thus, the non-prediction by the CAM–ICU or ICDSC did not refute the presence of delirium. Between the CAM–ICU and ICDSC, the ICDSC proved to be the more accurate instrument.

The management of and prognosis for delirium are affected by its subtype: hypoactive, hyperactive, mixed, and none. The DMSS–4, an abbreviated version of the Delirium Motor Symptom Scale, is a brief instrument for the assessment of delirium subtypes. However, it has not yet been evaluated in an intensive care setting.

We performed a prospective/descriptive cohort study in order to determine the internal consistency, reliability, and validity of the relevant items of the DMSS–4 versus the Delirium Rating Scale–Revised-98 (DRS–R-98) and the original DMSS in a surgical intensive care setting.

A total of 289 elderly, predominantly male patients were screened for delirium, and 122 were included in our sample. The internal consistency of the DMSS–4 items was excellent (Cronbach's α = 0.92), and between the DMSS–4 and DRS–R-98 the overall concurrent validity was substantial (Cramer's V = 0.67). Within individual motor subtypes, concurrent validity remained at least substantial (Cohen's κ = 0.65–0.81) and sensitivity high (69.8 to 82.2%), in contrast to those of the no-motor subtype, with less validity and sensitivity (κ = 0.28, 22%). Similarly, total concurrent validity between the DMSS–4 and the original DMSS reached perfection (Cramer's V = 0.83), as did agreement between the subtypes (κ = 0.83–0.92), while sensitivity remained high (88.2–100%). Only in those with delirium with no-motor subtype was agreement moderate (κ = 0.56) and sensitivity lower (67%). Specificity was high across all subtypes (91.2–99.1%). The DMSS–4 yielded very sensitive ratings, particularly for hypoactive and hyperactive motor symptoms, and interrater agreement was excellent (Fleiss's κ = 0.83).

We found the DMSS–4 to be a most reliable and valid brief assessment of delirium in characterizing the subtypes of delirium in an intensive care setting, with increased sensitivity to hypoactive and hyperactive motor alterations.

Studies on decisional capacity have primarily focused on cognitive disorders, whereas noncognitive disorders remain understudied. The purpose of our study was to assess decisional capacity across a wide spectrum of medical and psychiatric disorders.

More than 2,500 consecutive consults were screened for decisional capacity, and 336 consults were reviewed at Bellevue Hospital Center in New York. Sociodemographic and medical variables, medical and psychiatric diagnoses, as well as decisional capacity assessments were recorded and analyzed.

Consults for decisional capacity were most commonly called for in male patients with cognitive and substance abuse disorders. Less commonly, consults were called for patients with mood or psychotic disorders. Overall, about two thirds of patients (64.7%) were deemed not to have decisional capacity. Among medical diagnoses, neurological disorders contributed to decisional incapacity, and among the psychiatric diagnoses, cognitive disorders were most frequently documented in cases lacking decisional capacity (54.1%) and interfered more commonly with decisional capacity than substance abuse or psychotic disorders (37.2 and 25%). In contrast, patients with mood disorders usually retained their decisional capacity (32%). Generally, the primary treatment team's assessment was accurate and was confirmed by the psychiatric service.

Although decisional capacity assessments were most commonly requested for patients with substance abuse and cognitive disorders, the latter generally affected the ability to make healthcare decisions the most. Further, cognitive disorders were much more likely to impair the ability to make appropriate healthcare decisions than substance abuse or psychotic disorders.