Table 3. Consensus criteria for TRS.

We summarize the consensus guidelines for treatment resistant schizophrenia (TRS) presented by the Treatment Response and Resistance in Psychosis (TRRIP) Working Group (Howes et al., 2017).

A. Lack of consensus
TRRIP systematic review	95% of studies used different criteria to define TRS 50% did not report operationalized criteria
B. Diagnosis of TRS
Disease/functional status	At least moderate symptom severity           Describe positive, negative, and/or cognitive symptoms           Assess with standardized symptom rating scale At least moderate functional impairment           Assess with validated functional scale
Treatment response	Determination of treatment non-response     Defined as <20% symptom reduction over ≥6 weeks Determination of treatment resistance           Defined as non-response to ≥2 adequate treatment trials             Minimum: ≥2 different antipsychotics             Optimum: ≥2 different antipsychotics, including ≥1 longacting injectable antipsychotic (for ≥4 months) Determination of adequate treatment trial           Dosage: equivalent to ≥600 mg chlorpromazine daily           Duration: ≥6 weeks at adequate dose Determination of adherence           Defined as ≥80% prescribed doses taken           Assess with ≥2 sources - e.g. patient/caregiver reports, case notes, pill counts, dispensing charts           Monitoring: obtain antipsychotic plasma levels             Minimum: ≥1 draw             Optimum: ≥2 draws separated by ≥2 weeks (without notifying patient)
	C. Diagnosis of UTRS
Ultra-TRS	Meets above criteria for treatment resistance Plus non-response to adequate trial on clozapin           Dosage: midpoint of target dosage range (Obtain clozapine level twice with level >350ng/mL)           Duration: 3 months