RESUMO
INTRODUCTION: All symptoms in schizophrenia may impact functioning. Although Food and Drug Administration-approved medications typically benefit positive symptoms, negative symptoms are generally refractory to medication interventions. N-acetylcysteine's (NAC) influence on glutamatergic neurotransmission has been established. An emerging body of research has attempted to correlate this action with reduction in symptom severity, evaluating response in positive, negative, and cognitive symptom domains. METHODS: A literature review was performed to analyze available data on NAC intervention and improvement in the positive, negative, and cognitive symptom domains in patients with schizophrenia. Quality of evidence was systematically assessed to determine level of certainty in results. RESULTS: Three randomized controlled trials were identified. Across studies, negative symptoms decreased more with NAC compared to placebo; ranging between 11.9% and 24.1%. The assessment determined a low level of certainty regarding benefit of NAC on negative and cognitive symptoms and moderate certainty for NAC regarding findings of side effects and lack of benefit on positive symptoms. DISCUSSION: Consistent reporting of benefit in negative symptoms is found across studies of NAC intervention. These improvements are notable for symptoms that have generally remained refractory to medication intervention. Inconsistent benefit was reported in positive and cognitive symptoms. GRADE (grading of recommendations assessment, development and evaluation) assessment of current evidence indicates a low certainty of benefit for negative symptoms with standard use of NAC in patients with schizophrenia. However, a trial of this low-risk intervention may be warranted in patients with resistant negative symptoms and subsequent impaired functioning despite appropriate antipsychotic therapy as they may experience additional benefit in this symptom domain.
RESUMO
BACKGROUND: Long-acting injectable antipsychotics (LAIAs) have been developed to decrease medication nonadherence. LAIAs are usually given biweekly or monthly, with the exception of new 3-month and 6-week formulations. There has been no known evaluation regarding whether the frequency of LAIA formulation affects adherence. The purpose of this study is to evaluate whether there is a difference in adherence between LAIAs administered biweekly or monthly. METHODS: Eligible participants were identified from the Louis Stokes Cleveland VA electronic medical record as having an active prescription for a LAIA between September 1, 2009, and September 1, 2014. Participants were then evaluated using inclusion and exclusion criteria to determine study entrance. Medication possession ratios (MPRs) were calculated for each participant to determine adherence for comparison of objectives. Descriptive statistics and t tests were used to identify significant differences between groups. RESULTS: There were 128 participants enrolled based on eligibility criteria. There were no differences in MPRs for biweekly versus monthly administered LAIAs (0.98 versus 0.97, respectively; P = .691). No differences in adherence were observed between first- and second-generation LAIAs (0.98 versus 0.98, respectively; P = .975), or for risperidone LAI versus paliperidone palmitate (0.97 versus 0.99, respectively; P = .269). Hospitalizations were observed to decrease by 61% after LAIA initiation (P = .021). DISCUSSION: Based on the findings of this retrospective cohort review, there was no difference in adherence in patients prescribed biweekly versus monthly injected LAIAs. Patient preference and response, safety, tolerability, cost, and availability of follow-up appointments should be other factors to take into consideration for agent selection.
