In response to RFA-MH-18-705, this application develops and tests a novel treatment strategy for improving cognition in patients with schizophrenia (SZ), via Pharmacologic Augmentation of Cognitive Therapies (PACTs), and directly addresses a critical need for more effective treatments for these disabling impairments. Cognitive benefits in SZ patients can be achieved via ?bottom-up? sensory-based targeted cognitive training (TCT) therapies, but such treatments are time- and resource-intensive, and responses are incomplete and variable. This application tests a rational and empirically supported platform for augmenting the benefits of TCT in antipsychotic medicated SZ patients by adjunctive daily treatment of 20 mg memantine (MEM), an FDA approved medication for the treatment of cognitive dysfunction in Alzheimer's Disease. Recent meta-analyses of MEM augmentation in antipsychotic-medicated SZ patients have demonstrated its safety, tolerability, and effectiveness at improving scores on brief cognitive screening tests. We hypothesize that MEM will augment TCT learning and hence the clinical gains from TCT, and that this PACT approach will be most effective in biomarker-defined subgroups of patients. Preliminary support for these hypotheses comes from our proof-of-concept, randomized, controlled studies of single-dose exposure to MEM relative to placebo. In these studies, we found that MEM significantly enhanced learning in auditory discrimination, the key component of the TCT program which is known to drive the cognitive gains in SZ patients following 30-50h of TCT. We also found that a single dose of MEM significantly enhanced several biomarkers of early sensory information processing in antipsychotic medicated SZ patients. Dose-response and time course studies identified the optimal MEM dose (20 mg) for maximal pro-learning effects. This application conducts a careful assessment of this PACT strategy for SZ:
Aim 1) Confirmation of target engagement: 54 SZ patients will be tested to confirm that MEM (20 mg) enhances measures of TCT learning;
Aim 2) Efficient pilot testing: Subjects from Aim 1 will be randomized into 2 treatment arms (n=27/arm) for a double-blind placebo-controlled 30-session clinical trial of MEM+TCT vs. placebo+TCT, to determine whether daily dosing of MEM augments the magnitude, rate and/or durability of TCT gains, and whether these gains are associated with target engagement, using specific Go/No-Go criteria and outcome measures of symptoms, cognition and real-life function;
Aim 3) Predictive biomarker identification of the PACT response, based on cognitive, electrophysiological, and performance-based measures assessed pre- and post-TCT. This is a highly novel, high-risk high-reward application to develop a PACT-based treatment paradigm that will enhance cognition, improve recovery and enhance outcomes for patients with schizophrenia, and will determine whether a future, fully-powered ?Confirmatory Efficacy trial? of this approach is warranted.
Treatment of schizophrenia currently includes antipsychotic medications and cognitive therapies which improve some symptoms, but do not sufficiently restore cognitive functioning or reduce psychosocial disability. We hypothesize that medications that specifically target sensory information processing deficits, rather than psychotic symptoms per se, will significantly enhance the benefits of a sensory-based targeted cognitive training (TCT) intervention in patients with schizophrenia. We will complete a randomized, double-blind clinical trial to: 1) confirm that the drug memantine augments TCT learning; 2) determine whether memantine enhances the clinical benefits from a full 30 session course of TCT vs. TCT plus placebo in antipsychotic-medicated schizophrenia patients, and 3) determine if memantine's enhancement of TCT is most effective in biomarker-defined subgroups of patients.
