Background The clinical high-risk syndrome for psychosis (CHR-P) was first conceptualized 25 years ago and has provided an influential paradigm for early detection and intervention in psychosis. CHR-P syndrome patients are youth and young adults who are symptomatic and impaired and also at risk for developing overtly psychotic disorders. Most CHR-P individuals who will not develop psychosis will continue displaying other poor mental health outcomes at follow-up. CHR-P is an uncommon condition in the general population but is quite common, if under-recognized, in the population of adolescents and young adults presenting for initial psychiatric care. Two semi-structured interviews have most frequently been used to ascertain patients for CHR-P and to rate their severity of illness over time: the Structured Interview for Psychosis-risk Syndromes (SIPS) and the Comprehensive Assessment of At-Risk Mental States (CAARMS). The US National Institute of Mental Health spearheaded the effort to harmonize these two instruments. Harmonization was needed, despite identical attenuated positive symptom content and general overall similarity, because of six important differences in: 1) organization of attenuated positive symptom content into items, 2) scaling of items, 3) conceptualization of severity, 4) quantifying symptom frequency, 5) frank psychosis diagnosis criteria, and 6) CHR-P syndrome criteria. These efforts led to the creation of a new instrument: the Positive SYmptoms and diagnostic criteria for the CAARMS Harmonized with the SIPS (PSYCHS). Full harmonization has been achieved for attenuated positive symptom ratings and for psychosis diagnostic criteria, and the instrument generates partly harmonized diagnostic criteria for both CAARMS and SIPS as well as derived severity scores for both CAARMS and SIPS. The PSYCHS is being used in the AMP SCZ Observational Study for CHR-P ascertainment and attenuated positive symptom severity rating instead of individual SIPS or CAARMS assessment. When used in this way, studies can permit inclusion of participants who meet criteria for either CAARMS UHR or SIPS CHR-P Progression, and sensitivity analyses in a data supplement can then report whether findings differed by CAARMS vs SIPS ascertainment or when employing CAARMS vs SIPS severity ratings. This practice should facilitate comparing findings across studies and meta-analyses. A letter of intent to qualify the PSYCHS as a Clinical Outcomes Assessment Drug Development Tool has been accepted by the FDA (DDT-COA-000163). Manual and Training Materials The Interviewer Manual is available here. Versions Two versions of the PSYCHS have been developed: one for initial assessment called the Screening Version and one for follow-up assessment called the Follow-up Version. Both versions of the PSYCHS are designed to be used as highly adaptive on-line electronic data capture (EDC) instruments, presenting entry fields, instructions, and error messages to the interviewer only when needed based on previous responses and making needed calculations automatically. Implementation of the PSYCHS in an appropriate EDC platform for direct data entry during the interview is highly recommended. Although an interviewer's first administration can require several hours, experienced interviewers can expect to conduct initial interviews in 60-90 minutes and follow-up interviews in 45-60 minutes. On-line Screening and Follow-up Versions The AMP SCZ versions of the PSYCHS have been implemented in REDCap v13.7.9. Because of the extensive use of equations and branching logic to reveal or hide data entry fields, instructions, and error messages, it was necessary to divide each version into two halves. The data dictionaries for the two halves of the Screening Version are located here: part 1, part 2. The Follow-up Version was designed to be used with REDCap longitudinal data collection enabled. Information from previous visits is automatically piped into the current visit. Follow-up visits in AMP SCZ for CHR-P participants occur at baseline, conversion, and months 1, 2, 3, 6, 12, 18, and 24. Follow-up data dictionaries for this visit schedule are located here: part 1, part 2. Follow-up visits in AMP SCZ for healthy control participants occur at baseline, conversion, and months 2, 12, and 24. Data dictionaries for this visit schedule are located here: part 1, part 2. AMP SCZ welcomes the development of REDCap versions for other visit schedules and implementations of the PSYCHS versions in other EDC platforms. Paper Screening and Follow-up Versions Paper Versions (screen, follow-up) are provided for when it is not possible to use an EDC version. These versions do not contain the detailed instructions, adaptive skip-outs, or automated calculations that are available on-line. Since calculations are not made automatically, the interviewer will need to be thoroughly familiar with SIPS and CAARMS diagnostic and grouping criteria as shown in the PSYCHS Interviewer Manual, Tables 9-14 and in the descriptive publication. For Follow-up, the interviewer will also need to have reviewed PSYCHS ratings and diagnoses from the previous visit.