S196. TRANSCRANIAL MAGNETIC STIMULATION IN SCHIZOPHRENIA WITH PROMINENT NEGATIVE SYMPTOMS- A REVIEW OF THE LITERATURE

BACKGROUND: Negative symptoms in schizophrenia are associated with lower quality of life, worse functional prognosis and poorer response to the psychopharmacological treatment [1]. Many efforts have been made to find new approaches for negative symptoms, and neuromodulation techniques may represent a solution for these patients when antipsychotics have reached their limits of efficacy [2]. Transcranial magnetic stimulation (TMS) is based on the use of alternating magnetic fields to induce electrical current in the cortical areas, being mainly used for patients with treatment-resistant depression and it is considered safe and well tolerated [3]. METHODS: A narrative review of data regarding the efficacy of transcranial magnetic stimulation for patients with schizophrenia with prominent negative symptoms was performed. Papers published between January 2000 and July 2019 in the main electronic databases (PubMed, Cochrane, EMBASE, CINAHL) were included in this review. The keywords used for database search were “schizophrenia” and “negative symptoms” and “transcranial magnetic stimulation” or “repetitive transcranial magnetic stimulation”. RESULTS: The treatment of negative symptoms in schizophrenia with high frequency TMS has been associated with favorable results in clinical trials. The targeted zones were dorsolateral prefrontal cortex, either bilaterally or only on the left side. The results varied upon the stimulation regimen, including duration, frequency, uni- versus bilaterally application etc. Two meta-analyses were identified and their results supported an effect size from 0.58 to 0.63 [2,3]. However, negative results derived from well designed clinical trials exist, which show no difference in the Positive and Negative Syndromes Scale (PANSS) - negative symptom score between rTMS and sham rTMS [4,5]. An exploratory analysis of a large-scale trial showed the impact of rTMS on different negative symptom domains confirmed no additional beneficial effect of the actove comparative to sham rTMS [5]. Also, data exist about the potential of rTMS for increasing task-related in frontal areas in patients with schizophrenia with negative predominant symptoms, which may grant further exploration of the mechanisms underlying the effects of rTMS. DISCUSSION: Data about the efficacy of TMS in schizophrenia with negative symptoms are controversial, because both evidence to support its efficacy and its lack of efficacy exist in clinical trials. However, meta-analyses support an important size effect which may be comparable to that of the pharmacological treatment. REFERENCES: 1. Vasiliu O, Vasile D, Făinărea AF, et al. Analysis of risk factors for antipsychotic-resistant schizophrenia in young patients- a retrospective analysis. Romanian Journal of Military Medicine 2018;CXXI(1):25–29. 2. Dlabac-de Lange J, Knegtering R, Aleman A. Repetitive transcranial magnetic stimulation for negative symptoms of schizophrenia: review and meta-analysis. J ClinPsychiatry 2010;71:411–418. 3. Freitas C, Fregni F, Pascual_leone A. Meta-analysis of the effects of repetitive transcranial magnetic stimulation (rTMS) on negative and positive symptoms in schizophrenia. Schizophr Res 2009;108:11–24. 4. Mogg A, Purvis R, Eranti S, et al. Repetitive transcranial magnetic stimulation for negative symptoms of schizophrenia: a randomized controlled pilot study. Schizophr Res 2007;93:221–228. 5. Hansbauer M, Wobrock T, Kunze B, et al. Efficacy of high-frequency repetitive transcranial magnetic stimulation on PANSS factors in schizophrenia with predominant negative symptoms- results from an exploratory re-analysis. Psychiatry Res 2018;263:22–29.