What Domains of Quality of Life are Risk Factors for Depression in Patients with Epilepsy?

Hideki Azuma* and Tatsuo Akechi

Department of Psychiatry, Nagoya City University Graduate School of Medical Sciences, Japan

*Corresponding author: Hideki Azuma, Department of Psychiatry, Nagoya City University Graduate School of Medical Sciences, Japan

Received: June 20, 2014; Accepted: July 14, 2014; Published: July 16, 2014

Abstract

Depression affects quality of life (QOL) in patients with epilepsy, but this study investigated which domains of QOL represent risk factors for depression. Ninety-two patients were asked to complete the Quality of Life Inventory in Epilepsy-31-P (QOLIE-31-P) as a QOL questionnaire, the Side Effects and Life Satisfaction (SEALS) inventory to identify effects of antiepileptic drugs on cognition, and the Neurological Disorders Depression Inventory for Epilepsy (NDDI) for rapid screening of depression. Significant factors were entered into logistic backward elimination to investigate risk factors for depression. Major depression was seen in 18 of the 92 patients (19.6%). No significant differences were seen between depression and non-depression groups in seizure-related or demographic variables. However, NDDI score correlated with frequency of complex partial seizure. Energy/Fatigue and Emotional Well-Being subscales in QOLI-31-P and the Worry subscale in SEALS remained as QOL factors impacting on depression. Mean onset of depression was approximately 4 years before the time of the investigation. QOL subscales representing risk factors for depression were not seizures, but health-related QOL factors in QOLIE-31-P and SEALS. Confirmation of these scores may facilitate the management of depression and the achievement of better QOL in patients with epilepsy.

Keywords: Epilepsy; Depression; QOLIE-31-P; SEALS; NDDI

Abbreviations

QOL: Quality of Life; QOLIE-31-P: Quality of Life Inventory for Epilepsy-31-P; SEALS: Side Effects and Life Satisfaction Inventory; NDDI: Neurological Disorders Depression Inventory for Epilepsy; AED: Antiepileptic Drug; CPS: Complex Partial Seizure; HRQOL: Health-Related QOL; SF-36: Medical Outcomes Study Short Form; HADS: Hospital Anxiety and Depression Scale

Introduction

The prevalence of depression is higher in patients with epilepsy than in the general population, with the lifetime prevalence of depressive disorder increasing to approximately 30% [1]. Although some discussions have examined whether relationships between seizure frequency or control and depression are relevant [2-6], seizure severity has been considered as a more important factor for depression than seizure frequency [7,8]. On the other hand, depression reportedly has a greater effect than seizure frequency on quality of life (QOL) [9,10]. Many studies have identified depression as a significant determinant of QOL [11-14]. One study reported that risk factors for depression emerged as seizure worry and social functioning subscale in Quality of Life Inventory for Epilepsy-31 (QOLIE-31) [15]. The present study investigated which domains of QOL most impact on depression.

Methods

From May to December 2013, a total of 202 patients visited the epilepsy clinic in the department of psychiatry at Nagoya City University Hospital. Exclusion criteria were intellectual disability (n=78), dementia (n=11), pregnancy (n=1), severe psychosis (n=1), psychogenic seizures (n=3), and visit of a family member (n=5). Another 11 patients declined to complete the questionnaires. As a result, 92 patients were eligible for this study. These patients were diagnosed as according to the International League Against Epilepsy classification of seizures and epileptic syndromes [16,17]. They completed the modified version of the QOLIE-31 (QOLIE-31-P) [18,19] as a measure of QOL, the Side Effects and Life Satisfaction Inventory (SEALS) [20] as an indicator of the cognitive side effects of antiepileptic drugs (AEDs), the Neurological Disorders Depression Inventory for Epilepsy (NDDI) [21] for the detection of major depression. Demographic and seizure-related variables were also examined. The diagnosis of major depression in patients with NDDI score >16 was determined by a psychiatrist through a clinical interview in accordance with the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders [22]. QOLIE-31-P was widely used to indicate QOL in patients with epilepsy [18]. SEALS was developed to identify the effects of AEDs on cognition and affect, and was available as a QOL measure complementary to QOLIE-31 [23,24]. Cross-sectional data were analyzed as described below. This study was relatively small and naturalistic. The small sample size meant that a normal distribution of data could not be guaranteed. Group differences were investigated using the chi square test and Mann-Whitney U test. To identify the subscales in QOLIE-31-P and SEALS associated with depression, the significant parameters were inserted into the backward elimination method. Values of P<0.05 were considered statistically significant. Data analysis was performed using PASW Statistics version 18. The ethics committee of Nagoya City University Medical School approved the study protocol. Written informed consent to participate in this study was obtained from all patients prior to enrolment.

Results

Depression was identified in 18 of 92 patients (19.6%). The current episode in all subject fulfilled the criteria for unipolar major depression as described by DSM4. No differences between depression and non-depression group were evident in terms of seizure-related and demographic variables (Table 1). However, a correlation was seen between NDDI and frequency of CPS (more than once per year) (Spearman's rho=0.22, p=0.035) after controlling for age and sex. Overall scores and scores in each subscale for QOLIE-31-P and SEALS were worse in the depression group than in the non-depression group, with the exception of the Dysphoria subscale in SEALS (Table 1). Logistic backward elimination revealed the QOL subscales of lower Energy/Fatigue and Emotional Well-Being in the QOLIE-31-P and the higher Worry subscale in SEALS (Tables 2,3) had the most impacts on depression. These analyses were not controlled by seizure frequency, which was not a significant factor for depression. Two patients did not complete SEALS. Brain magnetic resonance imaging was inspected for 69 of the 92 patients. Seven of the 18 patients with depression were taking antidepressants or major tranquilizers at the time of the study. In the depression group, mean (standard deviation (SD)) time from onset of epilepsy to onset of depression was 15.7 (16.8) years and the duration of epilepsy at the time of investigation was 19.6 (15.6) years. Two patients showed depression preceding the onset of epilepsy. Four patients were newly diagnosed with depression in this investigation. The AEDs taken by patients are shown in Table 4.

Table 1: Demographic variables, seizure-related variables, QOLIE-31-P and SEALS in depression and non-depression groups.



  
     
    Depression group (n=18)
    Non- depression group (n=74)
    p
  
  
    Age (years)**
    42.5 (16.4)
    45.3 (14.7)
    0.49
  
  
    Sex (male/female)*
    10/8
    33/41
    0.44
  
  
    NDDI**
    18.4 (1.89)
    10.0 (3.0)
    <0.001
  
  
    Duration of education (years)**
    12.2 (2.5)
    12.5 (2.4)
    0.58
  
  
    Age at diagnosis (years)**
    22.9 (18.9)
    18.1 (15.3)
    0.31
  
  
    Duration of epilepsy (years)**
    19.6 (15.6)
    27.9 (15.2)
    0.08
  
  
    Symptomatic partial/primary generalized*
    17/1
    59/15
    0.18
  
  
    Complex partial seizure (CPS)*
    10
    34
    0.60
  
  
    Frequency of CPS (at least once    a month)*
    1
    5
    1.00
  
  
    Frequency of CPS (at least once    a year)*
    6
    16
    0.72
  
  
    Secondary generalized seizure*
    12
    41
    0.44
  
  
    Simple partial seizure*
    7
    27
    1.00
  
  
    Absence seizure*
    1
    5
    0.67
  
  
    Myoclonic seizure*
    0
    4
    0.41
  
  
    Tonic seizure*
    0
    1
    0.80
  
  
    Tonic-clonic seizure*
    0
    6
    0.26
  
  
    EEG abnormality*
    7
    41
    0.29
  
  
    Number of AED**
    1.9 (1.1)
    1.6 (1.0)
    0.17
  
  
    Marital status*
    10
    38
    0.80
  
  
    Childbirth*
    3
    19
    0.55
  
  
    Full-time work*
    7
    29
    1.00
  
  
    Part-time work*
    1
    7
    1.00
  
  
    Sheltered work*
    1
    0
    0.20
  
  
    Student*
    1
    2
    0.48
  
  
    Unemployed*
    3
    17
    0.75
  
  
    Housewife*
    2
    13
    0.73
  
  
    Retired*
    3
    6
    0.37
  
  
    QOLIE-31-P
     
     
     
  
  
    QOLIE overall score**
    46.9 (11.8)
    73.9 (15.4)
    <0.001
  
  
    Energy/Fatigue**
    36.1 (15.7)
    64.9 (19.6)
    <0.001
  
  
    Emotional Well-Being**
    36.2 (15.7)
    71.0 (18.0)
    <0.001
  
  
    Social Functioning**
    57.2 (19.0)
    79.8 (21.3)
    <0.001
  
  
    Cognitive Functioning**
    54.9 (21.8)
    82.2 (20.9)
    <0.001
  
  
    Medication Effects**
    56.0 (24.7)
    74.7 (23.6)
    0.003
  
  
    Seizure Worry**
    44.8 (28.5)
    68.6 (24.5)
    0.001
  
  
    Overall Quality of Life**
    36.1 (13.9)
    62.4 (16.2)
    <0.001
  
  
    SEALS
     
     
     
  
  
    SEALS overall score**
    54.8 (16.3)
    34.1 (14.1)
    <0.001
  
  
    Cognition**
    52.0 (21.4)
    27.0 (20.5)
    <0.001
  
  
    Dysphoria**
    50.0 (16.29
    44.5 (16.7)
    0.21
  
  
    Tiredness**
    50.1 (25.6)
    35.2 (19.7)
    0.014
  
  
    Temper**
    56.3 (24.2)
    30.3 (21.3)
    <0.001
  
  
    Worry**
    80.3 (15.9)
    45.2 (22.9)
    <0.001



Table 1:  Demographic variables, seizure-related variables, QOLIE-31-P and SEALS in depression and non-depression groups.

	Beta coefficient	Wald	p	Odds	95%CI
Energy/Fatigue	-0.072	4.90	0.027	0.93	0.87-0.99
Emotional Well-Being	-0.102	9.98	0.002	0.90	0.85-0.96

	Beta coefficient	Wald	p	Odds	95%CI
Worry	0.08	17.9	<0.0001	1.08	1.04-1.02

Antiepileptic drug	Number of patients (%)
Carbamazepine	30 (32.6%)
Valproate	24 (26.1%)
Phenytoin	18 (30.4%)
Phenobarbital	18 (19.6%)
Levetiracetam	11 (12.0%)
Clonazepam	10 (10.9%)
Lamotrigine	10 (10.9%)
Clobasam	6 (6.5%)
Topiramate	6 (6.5%)
Zonisamide	5 (5.4%)
Primidone	4 (4.4%)
Acetazolamide	1 (1.1%)
Diazepam	1 (1.1%)
Ethosuximide	1 (1.1%)
Sulthiame	1 (1.1%)

What Domains of Quality of Life are Risk Factors for Depression in Patients with Epilepsy?

Abstract

Abbreviations

Introduction

Methods

Results

Discussion

Conclusion

References