In its 2012's release guideline on therapy for schizophrenia, the EMA joined the FDA to acknowledge primary and persistent negative symptoms (PNS) as an unmet need in the treatment of schizophrenia. Functional brain imaging studies showed a correlation between NS and reduced perfusion in the left dorsolateral prefrontal cortex (L-DLPFC). Pre-frontal activation (PFA) using repetitive transcranial magnetic stimulation (rTMS) significantly improve PNS (meta-analyses: effect size SMD = 0.55, ΔPANSS-N = -2.5). Yet schizophrenia is likely to gather many different natural entities of distinct pathophysiological mechanisms. Pursuing a one-size-fits-all approach will not adapt to this diversity and might account for inconsistencies in the results.
Progressive periodic catatonia (PPC) is a rare psychotic phenotype (0.1 - 0.5 ‰) which has been shown to be longitudinally stable (30-years follow-up) and consistent within families (about 1 third of first-degree relatives are affected). The core of this phenotype is a disintegration of psychomotor processes which progresses with each relapse, resulting in a "deficit state", i.e., PNS, responsible for most social and occupational disabilities. The investigators and others reported PPC to come with hyper-perfusions in premotor cortices compared to controls or non-PPC chronic psychoses (nPPC). These hyper-perfusions discriminate PPC from nPPC or depressive patients (Sensitivity = 82%; Specificity = 95%). Last, in independent proof-of-principle studies the investigators and others have shown that premotor inhibition (PMI) using rTMS significantly improved PNS in PPC and that the most dramatic improvements followed personalized accelerated rTMS protocols (5 days of rTMS; CGI-improvement = 2 which is equivalent to ΔPANSS-N = -10; lasting > 1 month - vs virtually no change for PFA). The efficacy index was very good (no side effects).
the investigators hypothesize that: (1) in PPC, add-on personalized premotor inhibition (PMI) is more effective in reducing PNS than L-DLPFC activation (PFA); (2) patient stratification is relevant as personalized PMI will not be as effective in the nPPC group (even expected to be less effective than PFA).
