Chapter 5. Adverse Effects - Adverse Effects

Written by Juli Lawrence

Following ECT, patients also display retrograde amnesia. Deficits in the recall of both personal (autobiographical) and public information are usually evident, and the deficits are typically greatest for events that occurred temporally closest to the treatment (Janis, 1950; Cronholm and Molander 1961; Strain et al. 1968; Squire 1975; Squire et al. 1975, 1976, 1981; Weeks et al. 1980; Sackeim et al. 1986; Wiener et al 1986b; Sackeim et al 1993; McElhiney et al. 1995). The magnitude of the retrograde amnesia is greatest immediately following the treatment. A few days following the ECT course, memory for events in the remote past is usually intact, but there may be difficulty in recalling events that transpired several months to years prior to ECT. The retrograde amnesia over this time span is rarely complete. Rather, patients have gaps or spottiness in their memories of personal and public events. Recent evidence suggests that the retrograde amnesia is typically greater for public information (knowledge of events in the world) as compared to personal information (autobiographic details of the patient's life) (Lisanby et al. in press). The emotional valence of autobiographical events, i.e., memories of pleasant or distressful events, is not related to their likelihood of being forgotten (McElhiney et al. 1995).

As time from ECT increases, there is usually substantial reduction in the extent of retrograde amnesia. Older memories are more likely to be recovered. The time course for this shrinkage of retrograde amnesia is often more gradual than that for the resolution of anterograde amnesia. In many patients the recovery from retrograde amnesia will be incomplete, and there is evidence that ECT can result in persistent or permanent memory loss (Squire et al. 1981; Weiner et al. 1986b; McElhiney et al. 1995; Sobin et al. 1995). Owing to a combination of anterograde and retrograde effects, many patients may manifest persistent loss of memory for some events that transpired in the interval starting several months before and extending to several weeks following the ECT course. There are individual differences, however, and, uncommonly, some patients may experience persistent amnesia that extends back several years prior to ECT. Profound and persistent retrograde amnesia may be more likely in patients with pre-existing neurological impairment and patients who receive large numbers of treatments, using methods that accentuate acute cognitive side effects (e.g., sine wave stimulation, bilateral electrode placement, high electrical stimulus intensity).

To determine the occurrence and severity of cognitive changes during and following the ECT course, orientation and memory functions should be assessed prior to initiation of ECT and throughout the course of treatment (see Chapter 12 for details).

5.5. Adverse Subjective Reactions

Negative subjective reactions to the experience of receiving ECT should be considered adverse side effects (Sackeim 1992). Prior to ECT, patients often report apprehension; rarely, some patients develop intense fear of the procedure during the ECT course (Fox 1993). Family members are also frequently apprehensive about the effects of the treatment. As part of the consent process prior to the start of ECT, patients and family members should be given the opportunity to express their concerns and questions to the attending physician and/or members of the ECT treatment team (see Chapter 8). Since much of the apprehension may be based on lack of information, it is often helpful to provide patients and family members with an information sheet describing basic facts about ECT (see Chapter 8). This material should be supplemental to the consent form. It is also useful to make available video material on ECT. Addressing the concerns and educational needs of patients and family members should be a process that continues throughout the course. In centers that regularly conduct ECT, it has been found useful to have ongoing group sessions led by a member of the treatment team, for patients receiving ECT and/or their significant others. Such group sessions, including prospective and recently treated patients and their families, may engender mutual support among these individuals and can serve as a forum for education about ECT.

Shortly following ECT, the great majority of patients report that their cognitive function is improved relative to their pre-ECT baseline (Cronholm and Ottosson 1963b; Shellenberger et al 1982; Frith et al 1983; Pettinati and Rosenberg 1984; Weiner et al 1986b; Mattes et al 1990; Calev et al 1991; Sackeim et al. 1993 ); Coleman et al 1996). Indeed, recent research has shown that two months following completion of ECT the memory self-ratings of former patients are markedly improved relative to their pre-ECT baseline and indistinguishable from healthy controls (Coleman et al. 1996). In patients who have received ECT, memory self-ratings show little association with the results of objective neuropsychological testing (Cronholm and Ottosson 1963b; Frith et al 1983; Squire and Slater 1983; Weiner et al 1986b; Squire and Zouzounis 1988; Calev et al 1991a; Coleman et al 1996). Likewise, in healthy and neurological samples, subjective memory assessments have generally shown weak or no association with objective neuropsychological measures (Bennett-Levy and Powell 1980; Broadbent et al. 1982; Rabbitt 1982; Larrabee and Levin 1986; Sackeim and Stem 1997). In contrast, strong associations are observed between mood state and memory self-ratings among patients who have received ECT, as well as other populations (Stieper et al. 1951; Frith et al 1983; Pettinati and Rosenberg 1984; Weiner et al. 1986b; Mattes et al 1990; Coleman et al. 1996). In essence, patients who benefit the most from ECT in terms of symptomatic response typically report the greatest improvement in subjective evaluations of memory.

A small minority of patients treated with ECT later report that they have suffered devastating consequences (Freeman and Kendell 1980, 1986). Patients may indicate that have dense amnesia extending far back into the past for events of personal significance and/or that broad aspects of cognitive function are impaired such that they are no longer able to engage in former occupations. The rarity of these subjective reports of profound cognitive deficits makes determination of their absolute base rates difficult. Multiple factors likely contribute to these perceptions by former patients.

First, in some patients self-reports of profound ECT-induced deficits may be accurate. As noted, as with any medical intervention, there are individual differences in the magnitude and persistence of ECT's cognitive effects. In rare cases, ECT may result in a more dense and persistent retrograde amnesia that extends back to years prior to the treatment.

Second, some of the psychiatric conditions treated with ECT result in cognitive deterioration as part of their natural history. This may be particularly likely in young patients in their first psychotic episode (Wyatt 1991, 1995), and in older patients where ECT may unmask a dementing process. While in such cases, cognitive deterioration would have occurred inevitably, the experience of transient short-term side effects with ECT may sensitize patients to attribute the persistent changes to the treatment (Squire 1986; Sackeim 1992).

Third, as noted above, subjective evaluations of cognitive function typically show poor association with objective measurement and strong association with measures of psychopathology (Coleman et al. 1996). Only one study recruited patients with long-term complaints about effects of ECT and compared them to two control groups (Freeman et al. 1980). Objective neuropsychological differences among the groups were slight, but there were marked differences in assessments of psychopathology and medication status. Patients who reported persistent deficits due to ECT were less likely to have benefited from the treatment, and were more likely to be presently symptomatic and receiving psychotropic treatment (Freeman et al. 1980; Frith et al. 1983).