ECT-induced negative symptom improvements boost cognition, functioning in schizophrenia

Electroconvulsive therapy (ECT) or the delivery of a finely controlled electric current to the brain in patients with schizophrenia can effectively address negative symptoms, which in turn translates to improvements in overall function, as shown in a study from Singapore.

In an analysis involving patients with schizophrenia/schizoaffective disorder treated with ECT at the Institute of Mental Health (IMH), ECT-induced reductions in negative symptoms were strongly related to improvements in global functioning (direct effect correlation coefficient [r]: –0.496; p=0.001) and cognitive function (indirect effect r: –0.077; p=0.035). These outcomes were assessed using the Global Assessment of Function and the Montreal Cognitive Assessment, respectively. [Brain Sci 2022;12:545]

“Negative symptoms represent a core component of schizophrenia associated with significant diminution or absence of normal behaviours related to motivation and interest (eg, avolition, anhedonia, asociality) or expression (eg, blunted affect, alogia), which accounts for a large part of the poor functional outcome, cognition impairment, and long-term morbidity in patients with this disorder,” according to the investigators. [Lancet Psychiatry 2018;5:664-677; Am J Psychiatry 2005;162:495-506]

Treating the negative symptoms of schizophrenia remains a high unmet need, they added, as the current pharmacological or psychotherapeutic treatment approaches have been shown to yield only small effect sizes. [Neuropsychiatr Dis Treat 2020;16:519-534; Curr Treat Options Psychiatry 2016;3:133-150]

In light of the present data, the investigators concluded that ECT may be an effective approach to promote neurocognitive and functional recovery via an improvement in negative symptoms.

Predictors of negative symptom improvement

The study included 340 patients (average age 40.9 years, 51.2 percent female) who underwent an average of 7.2 ECT sessions. Most of them (80.6 percent) received bifrontal ECT. Negative symptoms significantly decreased in 196 (57.6 percent) patients; 53 (15.5 percent) showed no change, while 91 (26.7 percent) exhibited symptom worsening.

There were several factors that predicted negative symptom improvement following ECT, including the capacity to give consent to treatment (p=0.025), lithium prescription (p=0.006), more severe baseline negative symptoms (p<0.001), and voluntary admission (p=0.032).

However, the investigators acknowledged that ECT produced a smaller improvement in negative symptoms (20.2 percent from baseline) than in psychotic (41.9 percent; p<0.001) and manic symptoms (30.7 percent; p=0.033).

“The interpretation of our results may be biased by patient selection, ie, the majority of patients treated with ECT in our hospital were due to acute relapse and dominant positive symptoms. Thus, it remains unclear whether ECT is a [suitable] treatment tool specifically for patients with dominant negative symptoms,” the investigators said.

“Future studies of randomized controlled trials with patients of dominant negative symptoms may help to address this concern,” they added.