This randomized, double-blind, sham-controlled clinical trial aimed to investigate the effectiveness of inhibitory repetitive transcranial magnetic stimulation (rTMS) in reducing psychomotor slowing in patients with schizophrenia spectrum disorders. The study included 103 participants aged 18 to 60 years, who were divided into four groups: 1-Hz rTMS, iTBS, sham, and a waiting group. The primary outcome was the proportion of responders at week 3, defined as a 30% or greater reduction in the Salpêtrière Retardation Rating Scale (SRRS) score. The results showed that 1-Hz rTMS significantly reduced psychomotor slowing compared to sham, iTBS, and no treatment, with 68% of participants in the 1-Hz rTMS group achieving a response, compared to 32% in the sham group and 18% in the waiting group. The study also found that 63% of participants in the waiting group responded after receiving 15 sessions of 1-Hz rTMS. No serious adverse events were reported, and the treatment was well-tolerated. The findings suggest that inhibitory rTMS over the supplementary motor area may be a promising treatment for psychomotor slowing in psychosis, with potential benefits lasting up to 6 months.This randomized, double-blind, sham-controlled clinical trial aimed to investigate the effectiveness of inhibitory repetitive transcranial magnetic stimulation (rTMS) in reducing psychomotor slowing in patients with schizophrenia spectrum disorders. The study included 103 participants aged 18 to 60 years, who were divided into four groups: 1-Hz rTMS, iTBS, sham, and a waiting group. The primary outcome was the proportion of responders at week 3, defined as a 30% or greater reduction in the Salpêtrière Retardation Rating Scale (SRRS) score. The results showed that 1-Hz rTMS significantly reduced psychomotor slowing compared to sham, iTBS, and no treatment, with 68% of participants in the 1-Hz rTMS group achieving a response, compared to 32% in the sham group and 18% in the waiting group. The study also found that 63% of participants in the waiting group responded after receiving 15 sessions of 1-Hz rTMS. No serious adverse events were reported, and the treatment was well-tolerated. The findings suggest that inhibitory rTMS over the supplementary motor area may be a promising treatment for psychomotor slowing in psychosis, with potential benefits lasting up to 6 months.