A randomized clinical trial evaluated the effectiveness of inhibitory repetitive transcranial magnetic stimulation (rTMS) in reducing psychomotor slowing in psychosis. The study involved 88 adults with schizophrenia spectrum disorders and severe psychomotor slowing, who were randomly assigned to four groups: 1-Hz rTMS, intermittent theta burst stimulation (iTBS), sham rTMS, or a waiting group. Participants received 15 sessions of rTMS over the supplementary motor area over three weeks. The waiting group received 15 sessions of 1-Hz rTMS after the three-week period. 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 1-Hz rTMS group showed significantly higher response rates compared to the iTBS, sham, and waiting groups. At week 3, 68% of the 1-Hz rTMS group responded, compared to 36%, 32%, and 18% in the iTBS, sham, and waiting groups, respectively. The waiting group responded to 1-Hz rTMS after the three-week period, with 63% of participants responding. No serious adverse events were reported. The study suggests that inhibitory rTMS is a safe and effective treatment for psychomotor slowing in psychosis, with delayed onset effects. Future research should explore the neural mechanisms underlying the effects of rTMS on the supplementary motor area in psychosis.A randomized clinical trial evaluated the effectiveness of inhibitory repetitive transcranial magnetic stimulation (rTMS) in reducing psychomotor slowing in psychosis. The study involved 88 adults with schizophrenia spectrum disorders and severe psychomotor slowing, who were randomly assigned to four groups: 1-Hz rTMS, intermittent theta burst stimulation (iTBS), sham rTMS, or a waiting group. Participants received 15 sessions of rTMS over the supplementary motor area over three weeks. The waiting group received 15 sessions of 1-Hz rTMS after the three-week period. 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 1-Hz rTMS group showed significantly higher response rates compared to the iTBS, sham, and waiting groups. At week 3, 68% of the 1-Hz rTMS group responded, compared to 36%, 32%, and 18% in the iTBS, sham, and waiting groups, respectively. The waiting group responded to 1-Hz rTMS after the three-week period, with 63% of participants responding. No serious adverse events were reported. The study suggests that inhibitory rTMS is a safe and effective treatment for psychomotor slowing in psychosis, with delayed onset effects. Future research should explore the neural mechanisms underlying the effects of rTMS on the supplementary motor area in psychosis.