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High Incidence of Depression Among People with Epilepsy
Depressive disorders are common among adults in the USA, with an annual prevalence of 10% (Kessler et .al.). With the development of new medications, there has been a trend toward better identification and treatment of depression. Two recent systematic surveys have been made to ascertain the incidence of depression among people with epilepsy.
A postal survey of more than 150,000 households across the USA revealed that 1.5% of responding adults had epilepsy (Blum et. al.). A follow-up postal survey was answered by 775 people who reported having epilepsy, 395 people with asthma, and 362 people with no chronic medical condition (control group) (Ettinger et. al.). People were asked to describe their symptoms of depression using the Center for Epidemiology Studies - Depression Scale (CESD), a 20-item patient checklist. People also were asked: "Have you ever consulted a physician for depression?" and "Have you ever taken prescription medication for depression?"
Significantly more people with epilepsy had symptoms of depression than those with asthma or no chronic medical disorder (36.5% epilepsy, 27.8% asthma, 11.8% controls, p<0.001). People with epilepsy also were more likely to have "ever consulted a doctor for depression" than asthma or control respondents (32.9%, 22.3%, 11.2%, p<.001). They were also more likely to have "ever taken medication for depression" than asthma or control respondents (27.1%, 19.0%, 10.5%, p<0.001).
These data not only support the concept of a higher than expected impact of depression on people with epilepsy, but also contradict the notion that depression is simply a consequence of having any chronic disorder. Unfortunately, these data also show that many people were not diagnosed or treated for depression. The problem may be that patients are unaware of the symptoms of depression, assume it is part of their epilepsy, caused by the medication, or hide symptoms when with their doctor. Alternatively, doctors may not adequately evaluate symptoms of chronic depression, be unwilling to add another medication, or have concerns about seizure exacerbation due to an antidepressant.
We have some answers to these questions in several recent reports emanating from these surveys.
Quality of Life:
The impact of depression on health-related quality of life (HRQOL) was evaluated in a community sample of people with epilepsy (Cramer et. al.). Depression was categorized as severe (SEV), mild-moderate (MOD) or none (NO) based on CES-D scores. HRQOL was evaluated with the QOLIE-89.
This survey of a community sample of people with epilepsy confirms the high correlations between depression and patient-reported HRQOL. The use of self-report instruments to define current symptoms of depression and perceived severity and bother related to seizures also denotes the simplicity of using these instruments as screening tools in clinical practice. These data are a picture of the pervasive influence of clinical depression on multiple aspects patients' perceptions of their epilepsy.
These analyses demonstrate that clinical depression is significantly associated with poorer HRQOL among people with all types of seizures. Categorization of people by presence of depression differentiated HRQOL among people experiencing all types of seizures. Level of depression differentiated patients for HRQOL status whether seizures were controlled or continuing. The significant influence of even mild-moderate depression on people's perception of all aspects of their HRQOL suggests the importance of depression screening among people with epilepsy. Diagnosis and treatment of depression could be an important contribution to wellness of people with epilepsy whether or not seizures are controlled.
The impact of depression on self-reported seizure severity was evaluated in a community sample of people with epilepsy (Cramer et. al.). These analyses defined the associations between depression and recovery from seizures (based on seizure type, frequency, and severity) as measured by the Seizure Severity Questionnaire (SSQ, Cramer et. al.). Depression was assessed by the CES-D scale.
Seizure Severity Scale (SSQ):
Patient-reported assessment of seizures was made both as (a) categories of seizure frequency based on whether seizures had occurred recently (les than one week ago, 1-3 weeks ago, 1-3 months ago) or not recently (4-12 months ago, 1-2 years ago, more than 2 years ago), and (b) as a patient-rated assessment. The SSQ categorizes seizures into three phases as warning (aura), ictal activity, and post-ictal recovery. The recovery phase was further subdivided into three components as cognitive, emotional, and physical aspects of recovery, each rated for frequency, severity, and bothersomeness.
These analyses demonstrated that clinically depressed people with epilepsy perceived higher levels of severity and bother from seizures, indicating greater problems with perceived seizure recovery than non-depressed people experiencing similar types of seizures. The pervasive influence of depressive symptoms on reports of seizure activity suggests that people with epilepsy should be screened for depression and treated as needed.
Healthcare Resource Utilization:
The impact of depression on healthcare utilization was evaluated in a community sample of people with epilepsy (Cramer et. al.). Depression was assessed by the CES-D scale. The Sheehan Disability Scale (SDS) was used to ask about the frequency of disrupted by caused by epilepsy-related problems. All analyses were adjusted for seizure type and recency.
People with epilepsy who had mild-moderate and severe depression had two-fold and four-fold, respectively, increased numbers of visits to medical doctors compared to people with no depression. Those with severe depression received more psychiatric care (3.6+14 visits) than people with mild (0.88+3 visits) or no depression (0.36+3 visits, p<0.0001), as well as twice as many visits for emergency care (p=0.001) and four-fold higher days in hospital (p=0.002). SDS scores correlated with the amount of healthcare utilization. Yet, seizure type was not a significant factor in these differences.
These analyses documented the significant impact that comorbid depression has on amount of healthcare used by people with epilepsy (frequency of visits to physicians for medical, psychiatric and emergency care, as well as days in hospital). Finding that these differences were not related to seizure type indicates we cannot assume that people who have minor seizures or have not had a seizure for several months are unaffected by depression. Diagnosis and treatment of comorbid depression among people with epilepsy might be an important target to reduce overall healthcare utilization, and perhaps cost.
The message is clear that epilepsy extends beyond seizures. Simple self-report questionnaires, such as the CES-D used in this survey, can be employed to screen for depression. Once diagnosed, consideration should be given to treatment. The stigma of epilepsy need not be compounded with the stigma of untreated depression.
Written by: Joyce Cramer, epilepsy.com Editorial Board
Reviewed September 2004 by Steven C. Schachter, MD and Orrin Devinsky MD, epilepsy.com Editorial Board.
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