Repetitive TMS (rTMS) is the most widely used modality with a single session lasting 20–40 min, typically delivering between 1200-3000 magnetic pulses 13. Whether TMS increases or decreases the activity of the targeted neurons depends on the frequency of the magnetic pulses with 1 Hz and below (low frequency) being inhibitory and >1 Hz being excitatory (high frequency) 12. Transcranial magnetic stimulation (TMS) is a non-invasive neuromodulation technique in which a localized electrical field is elicited in underlying brain parenchyma through electromagnetic induction, generally limited to superficial cortical regions 10, 11.

Therefore, identification and development of efficacious treatments of negative symptoms is a priority 3, 9. Patients with predominantly negative symptoms are more resistant to treatment than patients with primarily positive symptoms, and negative symptoms are strongly associated with low daily functioning and poor long-term prognosis 6, 7, 8. The negative symptoms of schizophrenia are those representing absence/lessening of normal functions and include affective flattening, alogia, apathy and social withdrawal 5. Though positive symptoms (e.g., delusions and hallucinations) respond relatively well to pharmacological treatment, negative symptoms often do not respond to the same degree 2, 3, 4. Pharmacological treatment is the cornerstone of care in schizophrenia and other psychotic disorders 1. In conclusion, TMS appears to be an efficacious treatment option for patients with schizophrenia suffering from negative symptoms, but the optimal TMS parameters are yet to be established. There was, however, substantial heterogeneity and high risk of bias among the included studies. The pooled analysis showed statistically significant superiority of TMS (SMD = 0.41, 95%CI: 0.26 0.56, p-value 1 Hz was most efficacious. We identified 57 studies with a total of 2633 participants that were included in the meta-analysis. sham on negative symptoms in each study was quantified by the standardized mean difference (SMD, Cohen’s d) with 95% confidence intervals (95%CI) and pooled across studies using an inverse variance random effects model. Specifically, MEDLINE, EMBASE, Web of Science, and PsycINFO were searched for sham-controlled, randomized trials of TMS among patients with schizophrenia.

Here, we synthesize this literature in a systematic review and quantitative meta-analysis of double-blind randomized controlled trials of TMS in patients with schizophrenia. Several trials have shown preliminary evidence for the efficacy of transcranial magnetic stimulation (TMS) as a treatment for negative symptoms in schizophrenia.

Auditory hallucinations schizophrenia