Joint Crisis Plan Effectiveness in Preventing Relapses in Schizophrenia and Schizoaffective Disorder

Single blind multicentre randomised trial with parallel control groups. 2 groups: * SOS Intervention Group: benefits from the SOS Plan in addition to the usual follow-ups * "Control" Group: receive no additional intervention (only receive the routine follow-ups) OBJECTIVES : * To evaluate the effectiveness of the SOS Plan (JCP) in terms of the reduction in hospitalisations within 18 months of its development by comparison to the standard psychiatric care * To evaluate : 1. the cumulative length of hospitalisations (in days) in the two years following the development of the SOS plan 2. the type of hospitalisation (voluntary or compulsory) 3. the number of hospitalisations for a given subject 4. the number of crisis situations that may require the use of the SOS Plan 5. the clinical condition of the patient 6. the patient with the most responses to the SOS Plan in socio-demographic terms 7. the patient satisfaction in using the SOS Plan 8. the decisional autonomy during treatment 9. the quality of the therapeutic alliance 10. the length of the meeting to develop the SOS Plan 11. the quality of life 12. the medico-economic impact EXECUTION OF PRACTICAL RESEARCH : 1. The inclusion visit will be completed apart from a period of acute psychiatric decompensation, while the patient is capable of consenting to treatment. The inclusion visit will be completed within a hospital department before the patient is finally released from hospitalisation or during an outpatient follow-up. This involves placing the patient on the Positive And Negative Syndrome Scale (PANSS) to ensure that the patient's clinical condition allows him to consent to treatment. A score above 95 excludes the patient. The investigator also outlines the study and schedules visits. The patient then signs both the information letter and informed consent. A urine pregnancy test will be carried out on women of childbearing age. 2. Randomisation will be performed by a member of the SOS regional-referral team. For patients in the SOS Intervention group: * Preparatory interview with an SOS regional referrer * SOS Plan development meeting in the presence of the patient, the treating psychiatrist, one or more relatives, and an SOS regional referrer For patients in the control group: tracking the continuation of psychiatric care according to the standard care terms 3 ) Follow-up visits: for the two groups: 4 visits M6, M12, M18, M24 At each visit: meeting with an independent regional SOS assessor blind to allocation. For both of the groups: * Assessment of the clinical condition: placement on the PANSS scale * Number of psychiatric hospitalisations, types of hospitalisation, duration of hospitalisation since the last visit * Satisfaction assessment (numeric scale), of the therapeutic alliance (WAI), of decision-making autonomy (API), of quality of life (SF-36) For the SOS Intervention group: * Updating the SOS Plan after each relapse that leads to an unscheduled psychiatric hospitalisation lasting more than two weeks. * Updating the SOS Plan every 6 months in the absence of hospitalisation