The aim of this research is to find out if mobile phone text message reminders of appointments can help to address missed appointments in Psychosis Community Services. Another aim is to examine if fewer missed appointments result in clinical benefits for service users and in lower costs for Psychosis Community Services over a period of 6 months. 600 users from 2 London Psychosis Community Services will take part in this research. Each participant will be put into one of two groups, as s/he joins the study: In the first (experimental) group, each participant will receive appointment reminders for 6 months (7 and 1 day/s before each appointment), starting with the first available opportunity upon joining the study. In the second (control) group, each participant will not receive appointment reminders for 6 months. The choice of group for each individual will be made at random by a computer. Clinical information will be collected for 6 months from the time each participant joins the study, using, with his or her consent, their anonymised electronic medical records. The following clinical information will be compared between the experimental and control groups: Attendance of appointments, number of inpatient admissions, number of days in inpatient care, number of inpatient admissions under the mental health treatment act, number of referrals to a home treatment team, number of times patient has changed medication, health and social functioning. Service use, service costs and the cost-effectiveness of the reminder system will also be examined. Towards the end of their participation, service users, as well as mental health professionals, will be invited to express their views, concerns and suggestions in relation to the reminder service by completing a brief anonymised (service users) or anonymous (staff) questionnaire

Inclusion Criteria:

• Be a user of Psychosis Community Services
• Manifest at least a basic level of comprehension of the study (including its nature, purpose, procedures and implications) prior to enrollment, and adequate capacity to consent, as assessed by the University of California, San Diego Brief Assessment of Capacity to Consent (UBACC) scale.
• Own a mobile phone.
• Be willing to receive SMS reminders of appointments with the Psychosis Community Service.
• Provide written informed consent to participate in the study.

Exclusion Criteria:

• Is not a user of Psychosis Community Services.
• Cannot manifest at least a basic level of comprehension of the study (including its nature, purpose, procedures and implications) prior to enrollment, and/or adequate capacity to consent, as assessed by the University of California, San Diego Brief Assessment of Capacity to Consent (UBACC) scale.
• Does not own a mobile phone.
• Is under 18 years of age.