Does Gender Influence Electroconvulsive Therapy Sessions Required across Psychiatric Diagnoses? A 5-Year Experience from a Single Center

INTRODUCTION

Electroconvulsive therapy (ECT) is a well-established and commonly utilized somatic treatment when psychiatrists encounter severe or refractory mental disorders such as major depression with prominent suicide risk, recalcitrant psychosis, and acute catatonic states with inadequate response to pharmacotherapy.[12] Despite concerns about its side effects, most patients and caregivers approach the procedure as a life-saving treatment.[3] Although many clinical guidelines are available on practice and indications of ECT,[45] literature has less to divulge on number of sessions required for clinical response across the spectrum of common indications and whether gender may be a determinant of the same.

Knowledge on the required number of sessions will inform us about patient education, plan hospital stay, implement treatment strategies, and importantly prevent various side effects. In India, common diagnoses for which ECT has been prescribed are schizophrenia and mood disorders and lastly catatonia as an independent indication.[6] Indications, legal requirements, and practice of ECT have been shown to vary considerably across settings. More pertinently perhaps, this is one area where fidelity to clinical guidelines has been found insufficient.[7] In such a scenario, it is important for countries to have a valid and representative database about use and practice of ECT. With this background, we aimed at ascertaining the number of ECT sessions required to yield response and the gender influence on number of sessions required in patients with diagnoses of schizophrenia, mood disorders, and other acute and transient psychiatric disorders (other ATPD). The last category was chosen because, in our center, patients presenting with acute onset catatonic signs with no preceding mood or psychotic features are commonly assigned this diagnosis. As there is no national ECT registry in India, the present study will provide real world data on use and practice of ECT.

SUBJECTS AND METHODS

RESULTS

Over a 5-year period, 148 patients were administered ECT either as inpatients or outpatients. The sample comprised 60 males and 88 females. The mean age of the sample was 29.5 (± 11.3) years. The age range of the sample was between 18 and 61 years.

The distribution of diagnosis showed that mood disorders (bipolar affective disorder and recurrent depressive disorder) were the baseline diagnosis in more than half (55.4%, n = 82) of the individuals who underwent ECT. Schizophrenia was the diagnosis in 43 patients (29.1%) and other ATPDs in 22 patients (14.9%). The baseline diagnosis was not available in 1 patient. Subsequently, the total number of ECT sessions administered for each diagnostic category was analyzed [Table 1]. In the schizophrenia group (n = 43), patients received a mean of 9.7 (± 6.1) sessions of ECT while patients in the mood disorders (n = 82) category received a mean of 7.3 (± 3.8) sessions. Patients who had a diagnosis of other ATPDs (n = 22) received a mean of 5.4 (± 2.0) sessions. These diffeferences were statistically significant as per the Kruskal–Wallis test. We did not have data on the number of ECT sessions needed for two patients.

Table 1 Electroconvulsive therapy sessions administered across diagnoses

Although females with mood disorders and acute transient psychotic disorders required more number of ECT sessions than their male counterparts, the reverse was true for schizophrenia [Table 2]. However, none of these diffeferences were statistically significant.

Table 2 Gender differences in number of electroconvulsive therapy sessions received across diagnoses

DISCUSSION

Among the 148 patients who were administered ECT, mood disorder was the most frequent diagnosis followed by schizophrenia and other ATPD. This finding is in variance with earlier reports of ECT practice in Asia, where schizophrenia was observed to be the most common diagnosis.[6] Our findings may be artefactual as our sample had more females and affective diagnoses are more commonly encountered in females.[10] Hence, more studies from other centers in the country are required to validate these results.

The average number of ECT sessions required to yield therapeutic response in patients with schizophrenia, mood disorders, and other ATPD approximately coincide with that reported in cross-cultural literature.[11112] Similar to our results, catatonia as the sole indication for ECT has been shown to respond earlier compared to mood disorders and schizophrenia.[13] Our findings are also in line with systematic reviews on ECT practice, which have concluded that the minimum number required can range from 12 to 20 in schizophrenia,[3] 5–6 in catatonia,[13] 6–12 in mood disorders.[114]

The statistically significant difference in the number required across the three diagnoses indicates that the dose requirement to achieve response might be disorder-specific. However, one should exert caution in interpreting these findings as there are considerable variations in ECT parameters such as mode of delivery and electrode placement – unilateral or bifrontal or bitemporal,[15] intensities – threshold and suprathreshold,[1617] and frequency of sessions and variations in pulse–width – brief and ultrabrief,[12] all of which may conceivably influence stimulus dosing and response to ECT. Here, we have employed bitemporal threshold ECT for cases which, according to our knowledge, is most commonly practiced across India.

Previous studies have looked into the gender influence on the electrical charge delivered during ECT.[18] The present study is one of the few attempts to check the gender influence on number of ECT sessions. We could not find any significant effect of gender on ECT sessions required to induce a response across diagnostic categories. These findings are consistent with those from other cultures[19] and in resonance with the hypothesis that response to ECT is gender-neutral.[20] However, the skewed nature of our sample and inadequate numbers in subcategories such as other ATPD may indicate that these findings are not conclusive. Limitations of the study include its retrospective design, possible selection bias by virtue of being a single-center study, and nonmatching of sample across the studied groups. Further, we did not analyze gender diffeferences in electrical charge delivered during sessions or diffeferences in reasons for termination of ECT as we did not have access to this data. Given the naturalistic study design, the results are not affected by constraints of patient selection and ensuring strict protocols as in clinical trials. For this reason, they are also more reflective of real-world practice of ECT in Indian settings.

CONCLUSION

Mean number of ECT sessions are least for catatonia followed by mood disorders and schizophrenia. Number of sessions and dose required to achieve response may be disorder-specific. ECT-induced clinical response in major psychiatric disorders is independent of gender.