• Users Online: 43
  • Home
  • Print this page
  • Email this page
Home Current issue Archives Ahead of print Search Subscribe Instructions Submit article About us Editorial board Contacts Login 

 Table of Contents  
ORIGINAL ARTICLE
Year : 2018  |  Volume : 39  |  Issue : 1  |  Page : 28-34

Cognitive dysfunction in depressive and mixed episodes of bipolar disorder and major depressive disorder: is there a difference? egyptian experience


Department of Neurology and Psychiatry, Faculty of Medicine, University of Alexandria, Alexandria, Egypt

Date of Submission07-Sep-2017
Date of Acceptance10-Oct-2017
Date of Web Publication29-Jan-2018

Correspondence Address:
Hesham A Sheshtawy
Department of Neurology and Psychiatry, Faculty of Medicine, University of Alexandria, Alexandria, 21525
Egypt
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ejpsy.ejpsy_27_17

Rights and Permissions
  Abstract 


Background Depressive episodes are present in both bipolar disorder (BD) and major depressive disorder (MDD). Do cognitive dysfunction symptoms of depressive episode differ according to the disorder (MDD or BD)?
Aim of the work This work aimed to study the cognitive functions among patients with BD (depressive or mixed) and MDD during relapse.
Patients and methods This study included 90 patients during relapse diagnosed according to Diagnostic and Statistical Manual of Mental Disorders, 4th ed., Text Revision (DSM-IV-TR) (30 bipolar mixed, 30 bipolar depression, and 30 major depression) and 30 control participants. They were compared in terms of the severity of depression (using the Hamilton Depression Rating Scale), working memory (using the digit span test), processing speed (using the digit symbol test and trail making test A), verbal fluency (using the verbal fluency test), and executive function (using trail making test B).
Results The scores of BD patients were significantly worse than those of MDD patients in digit span tests (forward and backward), digit symbol test, verbal fluency test, and trail making tests (A and B). No significant difference was found between bipolar depression patients and bipolar mixed patients in the patterns of cognitive dysfunctions and the severity of cognitive dysfunctions.
Conclusion Bipolar patients experience significantly greater impairment than major depression patients. Other differentiators between the two disorders were that BD have lower age of illness onset, higher number of previous episodes, higher numbers of previous hospitalizations, and greater presence of psychotic features than MDD.

Keywords: bipolar disorder, cognitive dysfunction, differentiators, major depressive disorder


How to cite this article:
Abdel Aal MK, Molokhia TK, El Kholy OA, Sheshtawy HA. Cognitive dysfunction in depressive and mixed episodes of bipolar disorder and major depressive disorder: is there a difference? egyptian experience. Egypt J Psychiatr 2018;39:28-34

How to cite this URL:
Abdel Aal MK, Molokhia TK, El Kholy OA, Sheshtawy HA. Cognitive dysfunction in depressive and mixed episodes of bipolar disorder and major depressive disorder: is there a difference? egyptian experience. Egypt J Psychiatr [serial online] 2018 [cited 2018 Feb 17];39:28-34. Available from: http://new.ejpsy.eg.net/text.asp?2018/39/1/28/224007




  Introduction Top


Bipolar disorder (BD) is a chronic condition with repeated manic and depressive episodes alternating over a long period of time after disease onset with an extremely high risk of relapse and recurrence (Keller et al., 1993; Kanba et al., 2013).

Major depressive disorder (MDD) is a relapsing, remitting condition in most patients characterized by recurrent episodes of depression (Solomon et al., 2000).

Cognitive dysfunction is an impairment in cognitive ability closely linked to the functioning of specific brain areas, neural pathways, or cortical networks (Bearden et al., 2001).

Similar to that observed in schizophrenia (Green et al., 2004), cognitive deficits are also found in BD and MDD. In general, unipolar (UP) and bipolar (BP) patients have shown impaired performance in tests of attention, executive function, and memory (Marvel and Paradiso, 2004).

Some clinical factors can be associated with worsening of cognitive dysfunction in mood disorders. These include lifetime number of acute episodes, illness duration, history of psychosis, and number of hospital admissions (Robinson et al., 2006). The more these factors are present, the greater the cognitive impairment observed (MacQueen et al., 2001; Zubieta et al., 2001; Cavanagh et al., 2002; Clark et al., 2002; Martinez-Aran et al., 2004; Bora et al., 2007).

Depressive episodes are present in both BD and MDD. Do cognitive dysfunction symptoms of depressive episode differ according to the disorder (MDD or BD)?


  Aim of the work Top


The aim of the present work is to study the cognitive functions among patients with BD current episode depressive or mixed and patients with MDD during relapse.


  Patients and methods Top


To achieve the aim of this study, 120 participants were recruited from El-Hadra University Hospital psychiatric wards and the outpatient neuropsychiatric clinic in the main Alexandria University Hospital in the period from March 2015 to January 2016. They were divided into four groups distributed as follows:
  1. 30 BP patients with current episode depressive according to Diagnostic and Statistical Manual of Mental Disorders, 4th ed., Text Revision (DSM-IV-TR) criteria.
  2. 30 BP patients with current episode mixed according to DSM-IV-TR criteria.
  3. 30 Major depressive patients during relapse according to DSM-IV-TR criteria.
  4. 30 Healthy control participants matched in terms of age, sex, and education.


The sample was collected randomly on the basis of the following inclusion and exclusion criteria.

Inclusion criteria

  1. Diagnoses: BD current episodes: depressed and mixed and MDD during relapse
  2. Age: 18–50 years.
  3. Both sexes.
  4. Informed and written consent of all the participants in the study.


Exclusion criteria

  1. Refusal to participate in the study.
  2. Other psychiatric disorders, for example: comorbid substance use disorder, anxiety disorder.
  3. History of mental retardation or significant cognitive impairment.
  4. History of head trauma.
  5. History of substance dependence in the last year.
  6. History of electroconvulsive therapy in the last year.
  7. Chronic physical or neurological debilitating disorders, especially those affecting cognition, for example: endocrine disorders, Parkinson’s disease.


The participants were subjected to the following:
  1. Semistructured interview using DSM-IV-TR criteria for the diagnosis of BD and MDD (American Psychiatric Association, 2000).
  2. Hamilton Depression Rating Scale (HDRS-17) (Hamilton, 1960, 1967).
  3. Digit span test (for the assessment of working memory and attention) (Brebionet al., 2009; Koenigset al., 2009).
  4. Digit symbol test (for the assessment of processing speed) (Rosanoet al., 2008).
  5. Semantic verbal fluency test (animal naming) (assessment of verbal fluency) (Chenet al., 2000).
  6. Trail making test (A ‘assessing processing speed’ and B ‘assessing executive functions’) (Reitan, 1955).


Data were entered into a computer and analyzed using IBM SPSS software package, version 20.0 (Kirkpatrick and Feeney, 2013).


  Results Top


Demographic characteristics among the four groups studied

In terms of sex, there was no statistically significant difference between the four groups (P>0.05)

The bipolar depression patients’ group included 17 (56.7%) men and 13 (43.3%) women, the bipolar mixed patients’ group included 12 (40.0%) men and 18 (60.0%) women, the major depression patients’ group included 11 (36.7%) men and 19 (63.3%) women, and the control group included 17 (56.7%) men and 13 (43.3%) women.

In terms of age, there was no statistically significant difference between the four groups (P>0.05)

The bipolar depression patients’ age ranged between 19 and 40 years, with a mean of 27.67±5.93 years, the bipolar mixed patients’ age ranged between 17 and 42 years, with a mean of 30.0±8.17 years, the major depression patients’ age ranged between 22 and 49 years, with a mean of 31.40±7.19 years, and age of the participants in the control group ranged between 21 and 42 years, with a mean of 27.20±4.83 years.

In terms of employment, there was no statistically significant difference between the four groups (P>0.05)

The bipolar depression patients’ group included 15 (50.0%) employed individuals and 15 (50.0%) unemployed individuals, the bipolar mixed patients’ group included 13 (43.3%) employed individuals and 17 (56.7%) unemployed individuals, the major depression patients’ group included 17 (56.7%) employed individuals and 13 (43.3%) unemployed individuals, and the control group included 19 (63.3%) employed individuals and 11 (36.7%) unemployed individuals.

In terms of the duration of education, there was also no statistically significant difference between the four groups (P>0.05)

The bipolar depression patients’ group showed a range between 11 and 16 years, with a mean of 13.80±1.67, whereas the bipolar mixed patients’ group showed a range between 8 and 18 years, with a mean of 13.40±2.49 years. The major depression patients’ group showed a range between 12 and 18 years, with a mean of 14.20±2.07, whereas the control group showed a range between 10 and 19 years, with a mean of 14.20±2.58 years.

Clinical characteristics among the patient groups

In terms of the age at illness onset, number of previous episodes, number of previous hospitalizations, and presence of current or previous psychotic features, there was a statistically significant difference between the major depression patients’ group and both bipolar groups (bipolar depression and bipolar mixed) (P<0.001) ([Table 1]). However, there was no statistically significant difference between the bipolar mixed patients and the bipolar depression patients (P=0.306).
Table 1 Comparison between the patient groups according to clinical characteristics (n=30)

Click here to view


In terms of the duration of illness, there was no statistically significant difference between the groups (P>0.05).

Hamilton Depression Rating Scale among the patient groups

The bipolar depression patients’ score was in the range between 8.0 and 24.0, with a mean of 17.20±5.32, the score of the bipolar mixed patients was in the range between 8.0 and 25.0, with a mean of 16.73±5.09, and score of the major depression patients’ was in the range between 8.0 and 25.0, with a mean of 15.47±5.23. There was no statistically significant difference between the groups (P>0.05) ([Table 2]).
Table 2 Comparison between the patient groups according to Hamilton Depression Rating Scale (n=30)

Click here to view


Comparison between the different studied groups according to digit span, digit symbol, verbal fluency, and trail making A and B tests

The forward digit span test

The mean score of bipolar depression patients was 5.80±1.13, whereas the mean score of bipolar mixed patients was 5.90±1.18 ([Table 3]). However, the mean score of patients with major depression was 6.17±1.18, whereas the of the controls was 6.87±0.90. There was a statistically significant difference between the control group and both bipolar groups (bipolar depression and bipolar mixed) (P=0.005 and 0.002, respectively). There was no statistically significant difference between the major depression patients group and the other three groups (control, bipolar depression, and bipolar mixed) (P=0.072, 0.573, and 0.785, respectively). Also, there was no statistically significant difference between the bipolar depression patient group and the bipolar mixed patient group (P=0.985).
Table 3 Comparison between the different groups studied according to digit span, digit symbol, verbal fluency, and trail making A and B tests (n=30)

Click here to view


The backward digit span test

The mean score of bipolar depression patients was 4.07±1.14, whereas the mean score of bipolar mixed patients was 4.03±1.25. However, the mean score of patients with major depression was 5.40±1.16, whereas the mean score of the controls was 6.20±0.89. There was a statistically significant difference between the control group and the other three groups (bipolar depression, bipolar mixed, and major depression) (P<0.001, <0.001, and 0.032 respectively). Also, there was a statistically significant difference between the group of patients with major depression and both bipolar groups (bipolar depression and bipolar mixed) (P<0.001). There was no statistically significant difference between the bipolar depression patient group and the bipolar mixed patient group (P=0.999).

The digit symbol test

The mean score of bipolar depression patients was 36.07±11.81, whereas the mean score of bipolar mixed patients was 33.97±9.42. However, the mean score of patients with major depression was 37.17±9.90, whereas the mean score of the controls was 47.33±7.35. There was a statistically significant difference between the control group and the other three groups (bipolar depression, bipolar mixed, and major depression) (P<0.001, <0.001, and <0.001, respectively). There was no statistically significant difference between the major depression patient group and both bipolar groups (bipolar depression and bipolar mixed) (P=0.695 and 0.203, respectively). Also, there was no statistically significant difference between the bipolar depression patient group and the bipolar mixed patient group (P=0.668)

Verbal fluency test

The mean score of the bipolar depression patients was 10.77±3.16, whereas the mean score of bipolar mixed patients was 11.10±3.21. However, the mean score of patients with major depression was 13.17±2.57, whereas mean score of the controls was 15.33±1.79. There was a statistically significant difference between the control group and the other three groups (bipolar depression, bipolar mixed, and major depression) (P<0.001, <0.001, and 0.014, respectively). Also, there was a statistically significant difference between the major depression patients’ group and both bipolar groups (bipolar depression and bipolar mixed) (P=0.005 and 0.022, respectively). There was no statistically significant difference between the bipolar depression patients’ group and the bipolar mixed patient group (P=0.965).

The trail making test part A

The mean score of the bipolar depression patients was 58.83±20.11, whereas the mean score of the bipolar mixed patients was 72.43±39.97. However, the mean score of the major depression patients was 55.17±17.59, whereas the mean score of the controls was 40.53±15.50. There was a statistically significant difference between the control group and the other three groups (bipolar depression, bipolar mixed, and major depression) (P=0.001, <0.001, and 0.002, respectively). There was no statistically significant difference between the major depression patients’ group and both bipolar groups (bipolar depression and bipolar mixed) (P=0.554 and 0.117, respectively). Also, there was no statistically significant difference between the bipolar depression patients’ group and the bipolar mixed patients’ group (P=0.416)

The trail making test part B

The mean score of the bipolar depression patients was 159.07±32.31 whereas the mean score of the bipolar mixed patients was 172.67±55.16. However, the mean score of the major depression patients was 121.20±24.52, whereas the mean score of the controls was 106.53±26.11. There was a statistically significant difference between the control group and the other three groups (bipolar depression, bipolar mixed, and major depression) (P<0.001, <0.001, and 0.036, respectively). Also, there was a statistically significant difference between the major depression patients’ group and both bipolar groups (bipolar depression and bipolar mixed) (P<0.001 and <0.001, respectively). There was no statistically significant difference between the bipolar depression patients’ group and the bipolar mixed patients’ group (P=0.403).


  Discussion Top


In terms of cognitive impairment, the study indicated that the three patient groups showed impairment in a wide range of neuropsychological domains including processing speed, verbal fluency, executive function, working memory, and psychomotor speed, which is in agreement with Xu et al. (2012), who studied three groups of bipolar I (n=92), bipolar II (n=131), and unipolar depression patients (n=293) using a battery of neuropsychological tests both at baseline (during a depressive episode) and after 6 weeks of treatment, and compared them with 202 healthy individuals.

The main finding of this study is that bipolar depression patients during either a depressive episode or a mixed episode perform significantly worse than MDD patients during relapse in neuropsychological tests measuring executive functions (trail making test part B), working memory (digit span backward), and verbal fluency. This is similar to (Borkowska and Rybakowski, 2001), who studied neuropsychological frontal lobe tests in bipolar depression patients (n=15) and unipolar depression patients (n=30), and Wolfe et al. (1987), who studied Verbal memory deficits associated with major affective disorders.

The difference between BP patients during either a depressive episode or a mixed episode and MDD patients found in the current study was not caused by the intensity of the depressive symptoms during an acute episode, the duration of illness, the duration of education, and employment as there was no statistically significant difference between these three groups in the previous four factors mentioned. The difference was also not because of slow psychomotor performance as trail making test part A scores (which measure psychomotor speed) of these three groups were not different statistically. This may indicate that the difference among these three groups could be related to the difference in the pathogenesis of their underlying disorders.

In terms of attention (digit span forward) and psychomotor speed (trail making test part A), there was no significant difference between BP patients during either a depressive episode or a mixed episode and major depressive patients. This is similar to the results of Borkowska and Rybakowski (2001).

In the current study, among the bipolar subgroups; no significant differences were found between the depressed and the mixed patients in cognitive dysfunctions. This was similar to the findings of Ryan et al. (2012).

Employment and duration of education did not differ significantly between the patient groups and the control groups. This may indicate that illness does not constitute a major problem in employment. Also, mostly, illness was not a barrier against continuation of education. However, the age of illness onset was significantly lower in the bipolar (mixed and depression) patients’ groups than the major depression group. The difference in age of illness onset was statistically insignificant between the bipolar mixed and the bipolar depression groups. Therefore, lower age of illness onset can enable differentiation of whether the depressive episode is UP or BP. However, age of illness onset mostly cannot differentiate between bipolar mixed and bipolar depression.

Other differentiators between the BP patients’ groups and the major depression group were higher numbers of previous episodes, higher numbers of previous hospitalizations, and the presence of psychotic features (previously or currently). However, duration of illness and severity of depressive symptoms (measured by HDRS) were similar in all patient groups. Thus, mostly, the last two factors cannot enable differentiation of whether the depressive episode is UP or BP.


  Conclusion Top


BD patients and MDD patients have a similar pattern of cognitive impairment, but BP experience greater impairment than major depression patients. Other differentiators between the two disorders were that BP have lower age of illness onset, higher number of previous episodes, higher numbers of previous hospitalizations, and presence of psychotic features (previously or currently) than major depression patients. However, sex, duration of illness, and severity of depressive symptoms (measured by HDRS) were similar in all patient groups. Thus, mostly the last three factors cannot enable differentiation of whether the depressive episode is UP or BP.[26]

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
American Psychiatric Association (2000). Diagnostic and statistical manual of mental disorders : DSM-IV-TR. Washington, DC: American Psychiatric Association.  Back to cited text no. 1
    
2.
Bearden CE, Hoffman KM, Cannon TD (2001). The neuropsychology and neuroanatomy of bipolar affective disorder: a critical review. Bipolar Disord 3:106–153.  Back to cited text no. 2
    
3.
Bora E, Vahip S, Akdeniz F, Gonul AS, Eryavuz A, Ogut M et al. (2007). The effect of previous psychotic mood episodes on cognitive impairment in euthymic bipolar patients. Bipolar Disord 9:468–477.  Back to cited text no. 3
    
4.
Borkowska A, Rybakowski JK (2001). Neuropsychological frontal lobe tests indicate that bipolar depressed patients are more impaired than unipolar. Bipolar Disord 3:88–94.  Back to cited text no. 4
    
5.
Brebion G, David AS, Jones HM, Pilowsky LS (2009). Working memory span and motor and cognitive speed in schizophrenia. Cogn Behav Neurol 22:101–108.  Back to cited text no. 5
    
6.
Cavanagh JT, Van Beck M, Muir W, Blackwood DH (2002). Case-control study of neurocognitive function in euthymic patients with bipolar disorder: an association with mania. Br J Psychiatry 180:320–326.  Back to cited text no. 6
    
7.
Chen YL, Chen YH, Lieh-Mak F, Lieh MF (2000). Semantic verbal fluency deficit as a familial trait marker in schizophrenia. Psychiatry Res 95:133–148.  Back to cited text no. 7
    
8.
Clark L, Iversen SD, Goodwin GM (2002). Sustained attention deficit in bipolar disorder. Br J Psychiatry 180:313–319.  Back to cited text no. 8
    
9.
Green MF, Nuechterlein KH, Gold JM, Barch DM, Cohen J, Essock S et al. (2004). Approaching a consensus cognitive battery for clinical trials in schizophrenia: the NIMH-MATRICS conference to select cognitive domains and test criteria. Biol Psychiatry 56:301–307.  Back to cited text no. 9
    
10.
Hamilton M (1960). A rating scale for depression. J Neurol Neurosurg Psychiatry 23:56–62.  Back to cited text no. 10
    
11.
Hamilton M (1967). Development of a rating scale for primary depressive illness. Br J Soc Clin Psychol 6:278–296.  Back to cited text no. 11
    
12.
Kanba S, Kato T, Terao T, Yamada K (2013). Guideline for treatment of bipolar disorder by the Japanese Society of Mood Disorders, 2012. Psychiatry Clin Neurosci 67:285–300.  Back to cited text no. 12
    
13.
Keller MB, Lavori PW, Coryell W, Endicott J, Mueller TI (1993). Bipolar I: a five-year prospective follow-up. J Nervous Mental Dis 181:238–245.  Back to cited text no. 13
    
14.
Kirkpatrick LA, Feeney BC (2013). A simple guide to IBM SPSS statistics for version 20.0. Student ed. Belmont, CA: Wadsworth, Cengage Learning.  Back to cited text no. 14
    
15.
Koenigs M, Barbey AK, Postle BR, Grafman J (2009). Superior parietal cortex is critical for the manipulation of information in working memory. J Neurosci 29:14980–14986.  Back to cited text no. 15
    
16.
MacQueen GM, Young LT, Galway TM, Joffe RT (2001). Backward masking task performance in stable, euthymic out-patients with bipolar disorder. Psychol Med 31:1269–1277.  Back to cited text no. 16
    
17.
Martinez-Aran A, Vieta E, Colom F, Torrent C, Sanchez-Moreno J, Reinares M et al. (2004). Cognitive impairment in euthymic bipolar patients: implications for clinical and functional outcome. Bipolar Disord 6:224–232.  Back to cited text no. 17
    
18.
Marvel CL, Paradiso S (2004). Cognitive and neurological impairment in mood disorders. Psychiatr Clin North Am 27:19–36.  Back to cited text no. 18
    
19.
Reitan R (1955). The relation of the trail making test to organic brain damage. J Consulting Psychol 19:393–394.  Back to cited text no. 19
    
20.
Robinson LJ, Thompson JM, Gallagher P, Goswami U, Young AH, Ferrier IN et al. (2006). A meta-analysis of cognitive deficits in euthymic patients with bipolar disorder. J Affect Disord 93:105–115.  Back to cited text no. 20
    
21.
Rosano C, Newman AB, Katz R, Hirsch CH, Kuller LH (2008). Association between lower digit symbol substitution test score and slower gait and greater risk of mortality and of developing incident disability in well-functioning older adults. J Am Geriatr Soc 56:1618–1625.  Back to cited text no. 21
    
22.
Ryan KA, Vederman AC, McFadden EM, Weldon AL, Kamali M, Langenecker SA et al. (2012). Differential executive functioning performance by phase of bipolar disorder. Bipolar Disord 14:527–536.  Back to cited text no. 22
    
23.
Solomon DA, Keller MB, Leon AC, Mueller TI, Lavori PW, Shea MT et al. (2000). Multiple recurrences of major depressive disorder. Ame J Psychiatry 157:229–233.  Back to cited text no. 23
    
24.
Wolfe J, Granholm E, Butters N, Saunders E, Janowsky D (1987). Verbal memory deficits associated with major affective disorders: a comparison of unipolar and bipolar patients. J Affect Disord 13:83–92.  Back to cited text no. 24
    
25.
Xu G, Lin K, Rao D, Dang Y, Ouyang H, Guo Y et al. (2012). Neuropsychological performance in bipolar I, bipolar II and unipolar depression patients: a longitudinal, naturalistic study. J Affect Disord 136:328–339.  Back to cited text no. 25
    
26.
Zubieta JK, Huguelet P, O’Neil RL, Giordani BJ (2001). Cognitive function in euthymic bipolar I disorder. Psychiatry Res 102:9–20.  Back to cited text no. 26
    



 
 
    Tables

  [Table 1], [Table 2], [Table 3]



 

Top
 
 
  Search
 
Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
Access Statistics
Email Alert *
Add to My List *
* Registration required (free)

 
  In this article
Abstract
Introduction
Aim of the work
Patients and methods
Results
Discussion
Conclusion
References
Article Tables

 Article Access Statistics
    Viewed13    
    Printed0    
    Emailed0    
    PDF Downloaded11    
    Comments [Add]    

Recommend this journal


[TAG2]
[TAG3]
[TAG4]