Patients with schizophrenia experiences varying clinical courses in the symptoms and up to 30-60% of patients with schizophrenia do not respond sufficiently to antipsychotics. Treatment-resistant Schizophrenia (TRS) can have several reasons, including early onset, nonadherence to oral medication regimens, and persistent negative symptoms known as deficit syndrome. Patients with TRS experience frequent exacerbations, leading to the need for higher doses of antipsychotics to achieve a clinical result.

Recently, dopamine supersensitivity psychosis (DSP) and tardive dyskinesia (TD), both of which could be caused by inappropriate pharmacotherapy, as typified by excessive dosages of antipsychotics, have also been presumed relevant to TRS. Several lines of evidence suggest that both DSP and withdrawal psychosis are closely linked to the supersensitivity of dopamine D2 receptors; this could be caused by a potent blockade of the receptors by antipsychotics. Indeed our study recently has found that patients with DSP are overlapped with the concept of treatment-resistance, and these patients can be recovered by long-acting injectable form, via amelioration of Dopamine supersensitivity state. However, it was also observed that one group did not improve at the clinical symptomatic level, despite the presence of DSP.

Here, we try to verify relation in patients with treatment-resistant schizophrenia between several classes of antipsychotics or clinical symptoms and treatment process with oral antipsychotics after the initiation of RLAI. This study is a naturalistic, one-arm design with a 12-month observation period of a moderate sample size (N=115).