Time and Life Perception in the Terminally Ill: Its Utility in Screening for Depression

Abstract

Objective:

The objective was to explore the utility of a new three-item depression screening tool concerning time and life perception (TLP-3), compared with the DSM-IV criteria.

Methods:

This was a cross-sectional study of 63 Portuguese terminally ill patients, from May 2010 to November 2012. Patients were eligible if they fulfilled the following inclusion criteria: age ≥18 years old; having a life-threatening disease with prognosis of 6 months or less; no evidence of dementia or delirium, based on documentation within the medical chart or by clinical consensus; Mini Mental State score ≥20; being able to read and speak Portuguese; and provision of written informed consent. Participants were assessed for depression using DSM-IV criteria and the newly developed TLP-3. Screening performance for depression using the TLP-3 compared with DSM-IV was calculated using measures of sensitivity, specificity, positive and negative predictive values. Logistic regression was calculated with the aim of identifying variables with the best predictive ability for diagnosing depression.

Results:

After logistic regression analysis was made to all three items composing TLP-3, only two items were maintained (OR=2.9, 95% CI [0.9–8.7]; OR=7.6, 95% CI [0.9–65.3], respectively). This final regression model composed of two questions (TLP-2) was able to diagnose correctly 70% of the depressed patients with a sensitivity of 63% and a specificity of 74%. The area under the ROC curve was 72% (95% CI [59–85]).

Conclusion:

TLP-3 is a novel and clinically applicable approach to assessing depression among palliative care patients. Further investigation is needed on the psychological significance of time and life perception distortions, and its possible application to screen for depression among patients nearing end of life.

Introduction

Depression is a serious psychological problem in palliative care, affecting nearly 15% of terminally ill patients.¹ Clinicians often lack the knowledge and skills to identify psychological issues such as depression in this patient population.² Furthermore, doctors tend to avoid discussing and exploring these areas due to time constraints, which may cause further suffering and undermining of quality of life.^2–4 In frail and fatigued patients, typical of those found in the palliative care setting, screening tools need to be brief.

Research on brief screening tools for depression in palliative care has attracted wide interest. Mahoney and colleagues⁵ for example, showed that a single-item interview for depression was as accurate as the Geriatric Depression Scale in detecting depression in older adults in palliative care. Chochinov and colleagues⁶ found that the single question, “Are you depressed?” successfully screened for depression in 197 patients receiving palliative care for advanced cancer, with 100% sensitivity, specificity, and positive predictive value compared with the Schedule for Affective Disorder. A U.K. study was unable to replicate perfect sensitivity and specificity for this single item screening approach, although methodological variation between the two studies may have accounted for these differences.⁷

Altered time perception has been identified as a means of screening for psychological distress in palliative care. Based on William James's⁸ statement that “Subjective time may be perceived as shorter or longer than objective time,” Bayés and colleagues⁹ reported a new tool for screening suffering in patients with terminal cancer and AIDS. Patients were systematically asked, “How long did yesterday seem to you?” and their answers were examined relative to their psychological condition. The authors reported that subjective perception of time correlated well with subjective suffering in half the patients, although the origins of distress were not known. The authors concluded that their findings regarding time perception in terminally ill patients could be a starting point for future research to identify suffering or distress. Other authors, Hanneke van Laarhoven and colleagues, showed that advanced cancer patients perceived time as moving slowly and this was correlated with distress.¹⁰

In his work about time, emotions, and depression, Gallagher¹¹ writes that several phenomenological and experimental studies show that depressed subjects have a slowed experience of time flow and that, in comparison to patients in control conditions, depressed patients tend to be less focused on present and future events.

Despite the above, researchers continue to study the efficacy and characteristics of brief screening tools for psychological depression in patients with advanced diseases; the use of time and life perception in terminally ill patients has not as yet received much attention. In particular, the utility and validity of this approach has not been established. The objective of our study was to explore a new three-item depression screening tool concerning time and life perception (TLP-3), compared with the Structured Clinical Interview for DSM-IV¹² in a group of 63 Portuguese terminally ill patients.

Study Rationale: Case Vignettes that Triggered This Research

First case vignette

F.S. is a 32-year-old terminally ill woman suffering from an aggressive, chemotherapy resistant leg sarcoma. F.S. was being cared for in a palliative care program to help her with debilitating pain and nausea. One day, during one of her consultations and looking very sad, she told her palliative care physician (M.J.): “I feel like I'm frozen in time. Life is broken, shattered…. It's like I'm living in another dimension, in a parallel path: there was life without cancer and this parallel present pathway with the disease.”

Second case vignette

V.P. is a 68-year-old gentleman with end-stage multiple sclerosis. He spends all his days in bed, totally dependent on others for his activities of daily living. In conversation with his palliative care doctor (M.J.), after a very disturbing night struggling with dyspnea, he describes a very vivid feeling when looking at the clock in his hospital room: “You know doctor, it's funny how the clock—and the time it represents—looks different when you have multiple sclerosis like I do. Days are very long, like my multiple sclerosis movements.”

Based on these kinds of patient statements in two cases, we wondered if time and life perception or possible distortion might relate to depression in terminally ill patients, and if so, whether this altered perception might serve as a depression screening tool. In turn, we developed a three-item screening instrument, TLP-3, which has been included as part of a protocol for an ongoing randomized controlled trial (RCT).¹³ The development of TLP-3 was based on notions or perceptions of slowing or freezing of time; a sense that one's life is shattered or broken; and a feeling, as a result of being ill, of living one's life on a separate path (see Table 1).

Table 1.

The Three Sentences about Time and Life Perception (TLP-3)

Por favor coloque um X em cada afirmação, conforme ache que é verdadeira ou falsa. (Please put an X on each sentence, if you consider it true or false.)
	Verdadeiro (True)	Falso (False)
1. Sinto que a minha vida se quebrou, se partiu. (I feel like my life is shattered, broken.)	□	□
2. Parece que a vida passa ao meu lado e que não andamos no mesmo caminho. (It seems like life is passing me by and that we don't walk the same path.)	□	□
3. Para mim o tempo parece congelado, parado. (To me time seems frozen, stopped.)	□	□

Methods

Patients

Participants were receiving inpatient care in the palliative medicine unit of S. Bento Menni of Casa de Saúde da Idanha in Lisbon, which delivers palliative care to terminally ill patients. Recruitment took place from May 2010 to November 2012. Patients were deemed eligible if they fulfilled the following inclusion criteria: age ≥18 years old; having a life-threatening disease with prognosis of 6 months or less; no evidence of dementia or delirium, based on documentation within the medical chart or by clinical consensus; Mini Mental State score ≥20; being able to read and speak Portuguese; and provision of written informed consent. Mini Mental State score ≥20 was used because of the low performance status and relatively low educational levels of our patient sample.

Our study received ethical approval from the ethics committee of the Instituto das Irmãs Hospitaleiras do Sagrado Coração de Jesus - Casa de Saúde da Idanha. All patients gave informed written consent after the investigation protocol was explained.

Design and evaluation

Participants were assessed for depression using DSM-IV criteria¹² by the principal investigator (M.J.), blind to TLP-3 answers, and were asked to complete the newly developed TLP-3. TLP-3 was self-administered, but if patients were too tired or requested help, it could be presented orally by a trained nurse. All scales were assessed at the same time.

This study was part of an overall RCT¹³ (registered with www.controlled-trials.com/ISRCTN34354086) investigating the efficacy of dignity therapy on the psychosocial and existential suffering of terminally ill patients.

Statistical analysis

At first, descriptive analysis was performed in order to describe study participants. A screening analysis was performed for TLP-3 considering DSM-IV as the gold standard. Sensitivity, specificity, positive predictive and negative values were calculated for each TLP-3 question. In order to evaluate the predictive performance of TLP-3 questions we applied a logistic regression model with DSM-IV depression status as dependent variable. Variable selection was performed using the Backward Stepwise Method with the likelihood ratio test; p-value for variable entrance and elimination was set as 0.05 and 0.10, respectively.

Results

Of the 186 patients admitted to the palliative care ward between May 2010 and November 2012, 123 patients did not fulfill the inclusion criteria—mainly because of clinical deterioration; followed by not being able to read, write, or speak Portuguese; and for declining to participate. The final sample was comprised of 63 terminally ill individuals.

Response rate for the TLP-3 was 100%. Prevalence of depression was 38.1%. Summary demographic and illness data are presented in Table 2. Table 3 shows the screening performance of the TLP-3 compared with the DSM-IV criteria as the gold standard.

Table 2.

Summary Characteristics of the Participants (N=63).

Gender, n (%)
Male	31 (49.2)
Female	32 (50.8)
Age, years
mean (SD)	65.7 (13.3), range=28–90
≤65	33 (52.4)
>65	30 (47.6)
Race/ethnicity, n (%)
Caucasian	60 (95.2)
African	3 (4.8)
Marital status, n (%)
Single	14 (22.2)
Married/ common law	23 (36.5)
Divorced/separated	10 (15.9)
Widowed	16 (25.4)
Education, n (%)
<high school	39 (61.9)
≥high school	24 (38.1)
Religion, n (%)
Catholic	53 (84.1)
Other	10 (15.9)
Diagnosis, n (%)
Oncologic	58 (93.3)
Nononcologic	5 (6.7)
Palliative Performance Scale ^a
mean (SD), range	58.3 (17.6), 30–90
Mini Mental State
mean (SD), range	24.4 (1.9), 20–28

Palliative Performance Scale: 100% - healthy; 0% - death.

Table 3.

Screening Performance for Depression of the TLP-3 Compared with DSM-IV, in 63 Terminally Ill Patients

	DSM-IV
Questions of TLP-3	Sensitivity (%)	Specificity (%)	PPV	NPV
1. Sinto que a minha vida se quebrou, se partiu. (I feel like my life is shattered, broken.)	100	7.7	40.0	100
2. Parece que a vida passa ao meu lado e que não andamos no mesmo caminho. (It seems like life passes aside and that we don't walk the same path.)	62.5	66.7	53.6	74.3
3. Para mim o tempo parece congelado, parado. (To me time seems frozen, stopped.)	95.8	28.2	45.1	91.7

NPV, negative predictive value; PPV, positive predictive value; TLP-3, time and life perception – 3 sentences.

Logistic regression

We chose the Backward Stepwise Method with the aim of identifying variables with best predictive ability for diagnosing depression. After the analysis only items 2 and 3 were maintained (TLP-2) (OR=2.9, 95% CI [0.9 – 8.7]; OR=7.6, 95%CI [0.9 – 65.3], respectively). This final regression model composed of two questions was able to diagnose correctly 70% of the depressed patients (using a cut-point of 50%), with a sensitivity of 63%, specificity of 74%, and positive and negative predictive values respectively 60% and 73%. The area under the ROC curve was 72% (95% CI [59–85]). Hosmer and Lemeshow¹⁴ have provided a qualitative scale to evaluate the area under the ROC curve (AUC). AUC=0.5: no discrimination; 0.7≤AUC<0.8: acceptable discrimination; 0.8≤AUC<0.9: excellent discrimination; and AUC≥0.9: outstanding discrimination.

Discussion

Various attempts have been made to develop brief screening approaches for depression in the terminally ill.⁶ The work of Bayés and colleagues⁹ using time perception was the basis for using this concept as a means of detecting psychological suffering in terminally ill patients. Although intriguing, the issue of time perception in patients nearing end of life has not been investigated, developed, or clinically implemented.

The present study, while performed in a small sample of palliative care patients, provides new insight on a new potential screening tool for depression in patients who are terminally ill.

Among the strengths of this study, the first was the 100% response rate to the TLP-3. This suggests excellent acceptability and ease with which this instrument was applied, even in a sample of terminally ill patients with a poor performance status like ours (mean=58.3, SD=17.6). Only two of the three TPL-3 items (items 2 and 3) remained following the logistic regression modeling, suggesting that these items have the best predictive value in identifying depression (Table 4). Although DSM-IV continues to be used as a diagnostic tool for depression in terminally ill patients,¹⁵ it is not considered the best instrument for medically ill patients.¹⁶ Clearly, a two-item screening tool such as the TLP-2 might be easier and more acceptable for highly distressed patients encountering pain or fatigue that could limit their ability to engage in more-demanding screening approaches.

Table 4.

The Two Sentences about Time and Life Perception (TLP-2)

Por favor coloque um X em cada afirmação, conforme ache que é verdadeira ou falsa. (Please put an X next to each sentence, showing if you consider it true or false.)
	Verdadeiro (True)	Falso (false)
Parece que a vida passa ao meu lado e que não andamos no mesmo caminho. (It seems like life is passing me by and that we don't walk the same path.)	□	□
Para mim o tempo parece congelado, parado. (To me time seems frozen, stopped.)	□	□

Translation of the sentences is merely exemplificative.

Our study has some important limitations worth noting. Firstly, our sample was relatively small. However, the odds ratios in our regression model suggest that this screening approach shows some predictive ability in screening for depression within the palliative care setting.

Secondly, despite our rationale for choosing Mini Mental State score ≥20, it is possible that our study could have inadvertently included some minor mildly delirious patients.

The other limitation was the high prevalence of depression within the study sample. This high prevalence likely strengthened the screening properties of our new screening tool, while possibly diminishing its specificity and NPV, i.e., its ability to correctly diagnose nondepressed cases. Clearly, future research using TLP-3 should be undertaken in a more psychologically heterogeneous population in order to determine its broader screening performance among palliative care patients, namely its specificity.

Another limitation was the generalizability of TLP-3 to different samples of patients. Our study was conducted in a sample of inpatients, so may not be as generalizable to advanced cancer patients attending outpatient clinics. We think it is possible that hospitalized patients may have different time perception due to boredom and separation from their usual home activities.

Finally, the majority of the study's participants had end-stage cancer and few had nononcologic conditions, as in the case vignette of multiple sclerosis, which in part triggered our investigation. At this time, we cannot say if issues pertaining to altered time perception apply to other noncancer palliative care populations, such as patients with advanced organic diseases. Research examining this issue and the performance of TLP-2 or TP-3 could determine if our findings are cancer specific or more far reaching.

Although TLP-2 appears to have some characteristics that make it useful as a screening tool, we echo the caution raised by Mahoney and colleagues⁵ and Chochinov and colleagues,⁶ indicating that screening does not replace the all-important task of thorough and detailed clinical assessment. Hence, we think our findings should alert clinicians to the novel dimension of time perception distortions encountered in terminally ill patients. Further investigation may elaborate on the psychological significance of this phenomenon, ultimately determining whether this manifests into clinically meaningful insights or applications, including screening strategies for depression among patients nearing end of life.

Footnotes

Acknowledgments

We would like to thank Filipa Fareleira for her constant support. A special word of gratitude to Professor Chochinov. A word in memory of Isabel Levy for the scientific research scholarship from Associação Portuguesa de Cuidados Paliativos.

Author Disclosure Statement

No conflicting financial interests exist.

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