Memantine as an adjuvant in cognitive symptoms of schizophrenia with chronic course a follow up study

Schizophrenia is a complex and heterogenous psychiatric illness characterized by constellation of positive, negative and cognitive symptoms. In the chronic course, the cognitive impairment remains persistent leading to socio-occupational impairment. Few studies have used memantine as an adjunctive treatment, and observed a decrease in positive, negative symptoms and improvement in cognitive symptoms and functionality. Initially , only the dopaminergic hyperactivity in the mesolimbic pathway had been described. However , recent evidence points to the involvement of glutamatergic pathways and glutamate receptors , especially the N-methyl-D-aspartate glutamatergic receptors(NMDAr), in its pathogenesis. However, antipsychotics still reamin the mainstay of treatment. Memantine is a partial uncompetitive non selective voltage dependent NMDA receptor antagonist. This was officially licensed for the treatment of moderate to severe Alzheimers disease, and has a favorable safety and tolerability profile. In recent years, studies have found glutamatergic system participation in the etiopathogenesis of schizophrenia, especially through aberrant NMDA receptors functioning, affecting the spatial and temporal organization of excitation and inhibition in neural networks that mediate cognition and behavior. Thus, drugs that modulate this activity, such as amantadine and memantine, could theoretically be used in its treatment. Memantine has been hypothesized to have a neuroprotective action in schizophrenia and other psychiatric disorders. Few case reports have explored its role as an off-label use in psychotic disorders. Moreover its effect in delaying the cognitive decline of patients with Alzheimers disease reveals a potential role for treating cognitive impairment as well as for preventing the progression of illness in schizophrenia. Several studies have focused on adjunctive use of memantine in schizophrenia, which revealed equivocal results. In some studies, adjunctive memantine treatment has been reported to decrease positive and negative symptoms, and to improve cognitive and functional level in patients with schizophrenia. Hence, our study aims to explore the effectiveness of memantine in cognitive symptoms of schizophrenia.