Preliminary Results of a Cognitive Enhancement Therapy Protocol for Persistent Negative Symptoms in Schizophrenia Spectrum Disorders

Background and Purpose

Schizophrenia spectrum disorders (SSDs) are characterized by a complex interplay of positive, negative, and affective symptoms, which can contribute to poor quality of life, functioning, and overall life experiences. While advances in psychosocial interventions and pharmacotherapy have demonstrated capacity to ameliorate positive symptoms, many individuals with schizophrenia still experience significant negative symptom burden, which have been less responsive to treatment. Prior research in negative symptomatology has suggested that cognition and negative symptoms are linked and could prove to be a potential treatment target. This study reports on preliminary findings from a randomized trial of a cognitive remediation intervention designed to target severe and persistent negative symptoms.

Methods

A total of 26 participants diagnosed with SSDs were randomly assigned to either Cognitive Enhancement Therapy (CET), a cognitive remediation treatment, or Enriched Supportive Therapy (EST), a field standard psychosocial intervention, for 18 months. Assessments of cognition and symptomatology were collected at six-month intervals starting at baseline, and three months post study completion. Intent-to-treat linear mixed-effects models were conducted to examine differential cognition and negative symptom change trajectories between CET and EST.

Results

Differential treatment effects were detected for problem-solving neurocognitive domains at post-completion assessments (B = 42.31, p = .002), as well as a trend level effect (B = 7.24, p = .087) for overall neurocognition, with CET outperforming EST. Additionally, an emerging effect on the expression negative symptom domain indicates a potential post-treatment improvement in CET vs. EST. While models indicate improvement in social cognition and reduction of other negative symptom domains across the trial, no significant differential treatment effects were detected in the preliminary sample.

Conclusions and Implications

While these findings are preliminary and will require further interpretation across the full study population, CET has shown efficacy in improving cognition as well as key components of negative symptomatology. The absence of a social cognition effect may suggest difficulty in engaging this target in those experiencing persistent negative symptoms. Analysis of 1-year post intervention assessments will provide crucial insight into the durability and lasting impact of negative symptom improvement and cognitive gains.