Quality of Life in Patients With Bipolar Disorder: Defining and Measuring Goals

May 1, 2007

A complex and heterogeneous condition characterized by a variety of symptoms and marked variability in disease course, bipolar disorder is marked by episodes of depression, hypomania, mania, or psychosis and,patients can experience a mixture of emotional states.

Bipolar disorder (BD) is a complex and heterogeneous condition characterized by a variety of symptoms and marked variability in disease course. A patient with BD can experience episodes of depression, hypomania, mania, or psychosis and, indeed, can experience a mixture of emotional states or cycle rapidly between them. In fact, recent research has highlighted the prevalence of marked subsyndromal features between episodes,1 but despite currently available treatments, BD remains a chronic relapsing condition.2

Given the symptom profile of BD, it is not surprising that the diagnosis is typically associated with significant disability and impaired functioning. According to World Health Organization (WHO) estimates, BD was the 6th leading cause of disability worldwide among young adults at the turn of the century.3 For example, if BD develops in a woman at the age of 25, she may lose 9 years in life expectancy (because of cardiovascular and other medical problems), 14 years of productivity, and 12 years of good health.4 Disturbingly, the lifetime suicide rates of patients with BD (treated or not) may be as high as 15%.5

Beyond symptoms to quality of life
While outcomes in patients with BD have traditionally been assessed as objectively measured clinicalinformation (such as relapse rates, number of hospitalizations, or symptom reduction as rated by a clinician-rated scale), a number of arguments suggest the need for the addition of functional and quality-of-life (QOL) measures.6-8 It has been observed clinically, for example, that some patients appear to function poorly despite relatively few symptoms, while others function well in the context of relatively severe symptoms.7 Likewise, there is evidence for a disjunction between symptom change and QOL change in response to treatment, with the latter typically lagging substantially behind the former.9 Finally, as discussed later in this article, patients themselves attend to more than symptoms when assessing the success of their treatment, and it would be reasonable to expect that the treatment alliance would benefit when clinicians share this more holistic viewpoint.6

The movement toward a broader set of outcome measures in BD is consistent with a change in the zeitgeist of BD research in the past decade. Mirroring the developments that occurred in schizophrenia research a decade earlier,10 biopsychosocial models of BD have recently been proposed,11-13 and a number of adjunctive psychosocial treatments for BD have been found efficacious.14,15 Researchers from this contemporary tradition have called for expanded targets for therapy7 and, hence, an expanded range of outcome mea-surements in BD. Indeed, it may be in the area of functional outcomes that psychosocial interventions make their strongest contribution.16 As asserted by Harvey,17 for example: "recovery should not be defined merely by symptomatic remission or even syndromal remission; rather, recovery should include symptomatic recovery, syndromal recovery, functional recovery, and a return to an acceptable quality of life for the patient."

Although the terms "QOL" and "functioning" are often used interchangeably, it may be useful to distinguish between them. Functioning is typically clinician-assessed and refers to objective function in a variety of behavioral domains. In contrast, QOL is commonly understood as a subjective indicator of patient well-being. The WHO has described QOL as the "individuals' perception of their position in life in the context of the culture and value systems in which they live and in relation to their goals, expectations, standards, and concerns."18 Although the domains encompassed by QOL and functioning may overlap (eg, social, occupational, and independent living), the former are characterized by an emphasis on subjective assessment of satisfaction. This article focuses on the subjective assessments of QOL in BD. Given the limited evidence base, our review will not distinguish between a broad conceptualization of QOL and health-related quality of life (HRQOL), with the latter referring specifically to those aspects of life that are impacted by health or ill health.

Quantitative studies
Compared with the study of QOL in unipolar depression, research into QOL in BD has been sparse.10 However, to date, the literature permits preliminary conclusions on 2 fundamental questions; namely, the degree of QOL impairment in BD patients compared with that in nonclinical and other patient populations, and the differential impact on QOL of the phases of BD.19-22

Several studies have sought to determine the degree of QOL impairment experienced by patients with BD. Not surprisingly, QOL in populations with BD appears to fall far below that observed in general population samples. For example, one study using the medical outcome survey (MOS) SF-3623-the most widely used HRQOL measure in the BD population to date-compared scores of patients with BD (N = 44) with previously reported norms for a general population sample (N = 2474).24 The SF-36 contains 8 subscales that assess physical functioning, social functioning, role limitations (physical), role limitations (emotional), pain, mental health, general health, and vitality. The results of the study indicated that HRQOL was significantly compromised in patients with BD in all SF-36 domains except physical functioning as compared with the general population. While the study provided a useful initial comparison, its findings must be interpreted with caution because of the disparate sample sizes and the use of previously published norms for the HRQOL instrument.

More recent data are provided by Yatham and colleagues,25 who reported on SF-36 scores in a large sample of patients with BD type I (BDI) (N = 920) who either were currently depressed or had experienced a recent episode of depression. Scores were significantly lower across all scale domains in the group of patients with BD than in the general population in the United States, with the patients with BD scoring markedly lower in the mental health, vitality, social functioning, and role emotional domains.

A number of studies have investigated HRQOL in BD compared with other psychiatric conditions. One study from the Netherlands compared SF-36 scores in patients with BD (N = 136) with scores found in patients with a variety of other psychiatric disorders.26 Participants with BD showed significantly more impairment in most SF-36 domains compared with other participants. For example, in the domain of mental health, participants with BDI experienced significantly lower scores (62.3) than people with mood (75.2), anxiety (74.0), substance use (80.2), or no psychiatric disorders (85.8).

In the study by Yatham and colleagues,25 the SF-36 scores in their sample of patients with BD were compared with scores reported in 7 large studies of HRQOL in patients with unipolar depression. Scores on 4 domains (general health, social functioning, role-physical, and role-emotional) were consistently lower in the group with BDI than in the group with unipolar depression; however, the patients with unipolar depression tended to exhibit higher scores in the bodily pain domain.

Although hypomanic symptoms are used to distinguish BD from unipolar depression in the current DSM classification, much of the morbidity and mortality in BD appears to be a consequence of the depressive phase of the disorder, rather than the defining hypomanic or manic phases. Among a sample of 129 patients, those who experienced acute depressive or mixed depressive episodes were at significantly higher risk for suicide, panic disorder, and psychosis than those patients who experienced purely manic episodes.27

There is growing evidence that the deleterious impact of depressive episodes and subsyndromal depressive symptoms in BD extends to QOL and functioning.28-31 Altshuler and colleagues32 found that subthreshold depressive symptoms of BD were significantly predictive of impaired role functioning-specifically, impairment in work, home functioning, and relationships. Indeed, in this sample of 759 patients, odds of experiencing significant impairment in role functioning among patients with subthreshold depressive symptoms were 3 to 6 times greater than for those who were not depressed. Recent findings from the ongoing multicenter STEP-BD trial funded by the NIMH underscore the relationship between depressive symptoms and QOL in BD.33 By comparing the baseline clinical states of the first 2000 participants enrolled in the STEP-BD, Zhang and colleagues8 demonstrated that depressive symptoms were strongly associated with poorer emotional QOL (as measured by the SF-36 mental health subscale), even after relevant confounding variables were controlled for.

Growing evidence for the marked association between depressive symptoms and lowered QOL in BDI is clinically significant, given that depressive symptoms predominate over manic symptoms in patients with BDI and particularly those with BDII.1,34 A large proportion of the QOL challenge of BD may therefore be attributable to depression, consistent with some evidence that QOL scores may be lower in patients with BDII in comparison to patients with BDI.35

The lack of a disorder-specific QOL scale is a limitation of the existing quantitative literature on QOL in BD. Although key aspects of QOL in BD are captured in generic QOL and HRQOL instruments, some of the disorder's unique features (eg, financial indiscretion and hypersexuality when hypomanic) demand specific measurements.36 For this reason, our group has undertaken a program of research to develop a disorder-specific scale for BD (QOL.BD).37,38

Qualitative data
As part of the development of the disorder-specific scale, QOL.BD, we conducted a series of in-depth qualitative interviews to identify themes in the QOL impacts of BD.37 We sought the views of a representative sample of people in whom both BDI and BDII had been diagnosed. The sample included individuals with a range of illness severity, from those patients who had been clinically stable for several years to inpatients who were recovering from a severe episode of depression or mania. We also interviewed caregivers of people severely affected by BD, health care workers with expertise in BD, and international experts. In total, we conducted 35 interviews with persons who had BD, 5 with caregivers, and 12 with health care professionals or experts (identified by both convenience and purposive sampling).

Respondents described a wide variety of factors that influenced QOL, including the adverse effects of medications, occupation, level of education, physical functioning, environment, health care factors, leisure activities, routine, and sexuality. On the other hand, a number of patients were functioning exceptionally well despite their diagnosis, and a minority espoused the view that BD had opened new doors of opportunity (eg, improved career paths or social networks). On the whole, however, even these individuals described having undergone several years of hardship and adjustment before getting "back on track."

Some of the factors mentioned (eg, independence, stigma and disclosure, identity, and spirituality) are not frequently examined in relation to QOL, yet they appear to have a significant impact on people's ability to lead full lives in the context of BD. We are continuing to develop the QOL.BD in close consultation with patients and health care professionals with the aim of maximizing the validity of the resulting instrument.

There are currently no consensus guidelines for the clinical measurement of outcomes for QOL in BD. Drawing on our own research and related literature, however, we are able to make provisional recommendations for clinicians, as outlined in the Table.

    
   
 Only use assessment scales that have demonstrated validity in this patient population 

Concluding remarks
There has been a recent upsurge of interest in measuring QOL in BD. Although research is at an early stage, there is no doubt that symptom measures alone constitute a limited assessment of BD outcomes, and more valid understandings (scientifically and clinically) are achieved with the addition of QOL measures. Existing research has revealed, for example, the marked negative impact of BD on QOL, a disjunction between symptom level and functional outcome in BD, and the apparent primacy of depressive over hypomanic symptoms in BD QOL outcomes.

In sum, the emerging body of research clearly suggests that it is both feasible and important to assess QOL in patients with this complex condition. For the practicing clinician, routinely adding a QOL measure to outcome monitoring will enrich understanding of patient progress, with consequent benefits for tailoring treatment regimens and for the therapeutic alliance.

References:

References1. Judd LL, Schettler PJ, Akiskal HS, et al. Long-term symptomatic status of bipolar I vs. bipolar II disorders. Int J Neuropsychopharmacol. 2003;6:127-137.
2. DePaulo JR Jr. Bipolar disorder treatment: an evidence-based reality check. Am J Psychiatry. 2006;163: 175-176.
3. Murray CJ, Lopez AD. Alternative projections of mortality and disability by cause 1990-2020: Global Burden of Disease Study. Lancet. 1997;349:1498-1504.
4. US DHEW Medical Practice Project. A State of the Service Report for the Office of the Assistant Secretary for the US Dept of Health, Education and Welfare. 1979.
5. Simpson SG, Jamison KR. The risk of suicide in patients with bipolar disorders. J Clin Psychiatry. 1999;60 (suppl 2):53-56; discussion 75-76, 113-116.
6. Keck PE Jr. Defining and improving response to treatment in patients with bipolar disorder. J Clin Psychiatry. 2004;65(suppl 15):25-29.
7. Colom F, Vieta E. A perspective on the use of psychoeducation, cognitive-behavioral therapy and interpersonal therapy for bipolar patients. Bipolar Disord. 2004;6:480-486.
8. Zhang H, Wisniewski SR, Bauer MS, et al. Comparisons of perceived quality of life across clinical states in bipolar disorder: data from the first 2000 Systematic Treatment Enhancement Program for Bipolar Disorder (STEP-BD) participants. Compr Psychiatry. 2006;47:161-168.
9. Namjoshi MA, Rajamannar G, Jacobs T, et al. Economic, clinical, and quality-of-life outcomes associated with olanzapine treatment in mania. Results from a randomized controlled trial. J Affect Disord. 2002;69:109-118.
10. Michalak EE, Murray G, Young AH, Lam RW. Quality of life impairment in bipolar disorder. In: Ritsner M, ed. Quality of Life Impairment in Schizophrenia, Mood and Anxiety Disorders: From Brain Functions to Clinical Practice. New York: Springer; 2007.
11. Frank E, Swartz HA, Kupfer DJ. Interpersonal and social rhythm therapy: managing the chaos of bipolar disorder. Biol Psychiatry. 2000;48:593-604.
12. Jones SH. Circadian rhythms, multilevel models of emotion and bipolar disorder: an initial step towards integration? Clin Psychol Rev. 2001;21:1193-1209.
13. Grandin LD, Alloy LB, Abramson LY. The social zeitgeber theory, circadian rhythms, and mood disorders: review and evaluation. Clin Psychol Rev. 2006;26:679-694.
14. Scott J, Gutierrez MJ. The current status of psychological treatments in bipolar disorders: a systematic review of relapse prevention. Bipolar Disord. 2004;6:498-503.
15. Scott J, Colom F, Vieta E. A meta-analysis of relapse rates with adjunctive psychological therapies compared to usual psychiatric treatment for bipolar disorders. Int J Neuropsychopharmacol. 2007;10:123-129.
16. Miklowitz DJ, Johnson SL. The psychopathology and treatment of bipolar disorder. Annu Rev Clin Psychol. 2006;2:199-235.
17. Harvey PD. Defining and achieving recovery from bipolar disorder. J Clin Psychiatry. 2006;67(suppl 9):14-18; discussion 36-42.
18. The WHOQOL Group. The World Health Organization Quality of Life assessment (WHOQOL): position paper from the World Health Organization. Soc Sci Med. 1995; 41:1403-1409.
19. Namjoshi MA, Buesching DP. A review of the health-related quality of life literature in bipolar disorder. Qual Life Res. 2001;10:105-115.
20. Dean BB, Gerner D, Gerner RH. A systematic review evaluating health-related quality of life, work impairment, and healthcare costs and utilization in bipolar disorder. Curr Med Res Opin. 2004;20:139-154.
21. Revicki DA, Matza LS, Flood E, Lloyd A. Bipolar disorder and health-related quality of life: review of burden of disease and clinical trials. Pharmacoeconomics. 2005; 23:583-594.
22. Michalak EE, Yatham LN, Lam RW. Quality of life in bipolar disorder: a review of the literature. Health Qual Life Outcomes. 2005;3:72.
23. Stewart AL, Hays RD, Ware JE Jr. The MOS short-form general health survey: reliability and validity in a patient population. Med Care. 1988;26:724-735.
24. Arnold LM, Witzeman KA, Swank ML, et al. Health-related quality of life using the SF-36 in patients with bipolar disorder compared with patients with chronic back pain and the general population. J Affect Disord. 2000; 57:235-239.
25. Yatham LN, Lecrubier Y, Fieve RR, et al. Quality of life in patients with bipolar I depression: data from 920 patients. Bipolar Disord. 2004;6:379-385.
26. ten Have M, Vollebergh W, Bijl R, Nolen WA. Bipolar disorder in the general population in The Netherlands (prevalence, consequences and care utilisation): results from The Netherlands Mental Health Survey and Incidence Study (NEMESIS). J Affect Disord. 2002;68:203-213.
27. Dilsaver SC, Chen YW, Swann AC, et al. Suicidality, panic disorder and psychosis in bipolar depression, depressive-mania and pure-mania. Psychiatry Res. 1997; 73:47-56.
28. Vojta C, Kinosian B, Glick H, et al. Self-reported quality of life across mood states in bipolar disorder. Compr Psychiatry. 2001;42:190-195.
29. Scott J, Paykel E, Morriss R, et al. Cognitive-behavioural therapy for severe and recurrent bipolar disorders: randomised controlled trial. Br J Psychiatry. 2006; 188:313-320.
30. Altshuler LL, Gitlin MJ, Mintz J, et al. Subsyndromal depression is associated with functional impairment in patients with bipolar disorder. J Clin Psychiatry. 2002; 63:807-811.
31. Post RM, Denicoff KD, Leverich GS, et al. Morbidity in 258 bipolar outpatients followed for 1 year with daily prospective ratings on the NIMH life chart method. J Clin Psychiatry. 2003;64:680-690.
32. Altshuler LL, Post RM, Black DO, et al. Subsyndromal depressive symptoms are associated with functional impairment in patients with bipolar disorder: results of a large, multisite study. J Clin Psychiatry. 2006;67:1551-1560.
33. Sachs GS, Thase ME, Otto MW, et al. Rationale, design, and methods of the systematic treatment enhancement program for bipolar disorder (STEP-BD). Biol Psychiatry. 2003;53:1028-1042.
34. Judd LL, Akiskal HS, Schettler PJ, et al. The long-term natural history of the weekly symptomatic status of bipolar I disorder. Arch Gen Psychiatry. 2002;59:530-537.
35. Cooke RG, Robb JC, Young LT, Joffe RT. Well-being and functioning in patients with bipolar disorder assessed using the MOS 20-ITEM short form (SF-20). J Affect Disord. 1996;39:93-97.
36. Patrick DL, Deyo RA. Generic and disease-specific measures in assessing health status and quality of life. Med Care. 1989;27:S217-S232.
37. Michalak EE, Yatham LN, Kolesar S, Lam RW. Bipolar disorder and quality of life: a patient-centered perspective. Qual Life Res. 2006;15:25-37.
38. Michalak EE, Yatham LN, Wan DD, Lam RW. Perceived quality of life in patients with bipolar disorder. Does group psychoeducation have an impact? Can J Psychiatry. 2005;50:95-100.
39. Ware JE, Kosinski M, Keller SD. SF-36 Physical and Mental Health Summary Scales: A User's Manual. Boston: The Health Institute, New England Medical Center; 1994.
40. Endicott J, Nee J, Harrison W, Blumenthal R. Quality of Life Enjoyment and Satisfaction Questionnaire: a new measure. Psychopharmacol Bull. 1993;29:321-326.
41. Lam R, Michalak E, Swinson R. Assessment Scales in Depression, Mania and Anxiety. London: Taylor and Francis; 2005.
42. Keck PE Jr, McElroy SL, Strakowski SM, et al. 12-Month outcome of patients with bipolar disorder following hospitalization for a manic or mixed episode. Am J Psychiatry. 1998;155:646-652.