Lambeth Early Onset (LEO) and Outreach & Support in South London (OASIS) service


Dr Paddy Power, Lambeth Early Onset Service, 108 Landor Road, London SW9 9NT, UK. Email:


Aim:  To establish a comprehensive phase-oriented early intervention service for young people with early psychosis in south London and to evaluate its effectiveness in delivering user friendly interventions and better outcomes.

Methods:  The Lambeth Early Onset (LEO) and Outreach & Support in South London (OASIS) service has been developed incrementally over the last 6 years into 4 teams each addressing one of the phases of early psychosis: (i) prodrome/ultra-high risk (ii) untreated psychosis (c) acute inpatient treatment and (d) recovery/ relapse prevention phases. Research and evaluation have been integral to each team’s development with three of the teams configured as Randomised Controlled Trials.

Results:  During the first 6 years, 1255 young people in Lambeth were referred for assessment (963 to LEO and 292 to OASIS). Of them 578 were diagnosed as suffering from first episode psychosis (some before or after they presented to OASIS), 450 have been followed up in Lambeth by the LEO Community Team and 40% discharged back to GPs in remission at the end of their two years of follow-up. Compared to standard service, patients’ delays in accessing treatment are less, and outcomes at 18 months are better.

Conclusions:  The LEO and OASIS service now provide most of the mental health service requirements for young people with early psychosis in Lambeth. It represents good value for money and improved outcomes for clients. Further interventions are planned and ultimately it will be possible to evaluate the impact of each incremental step in the service’s development.


The Lambeth Early Onset (LEO) and Outreach and Support in South London (OASIS) service is one of the first of the 117 early intervention services rolled out across England over the last decade.1 It has been running for 6 years and has developed into a ‘standalone’ service that now provides most of the mental health service requirements for young people experiencing their first episode of psychosis. LEO and OASIS is an integral part of a borough-based public adult mental health service (South London and Maudsley NHS Foundation Trust) and has close links to adolescent mental health, primary care, social and community services. It serves the inner city borough of Lambeth in south London and provides a 2-year follow-up service for any of the borough’s 16–35 year olds presenting to mental health services for the first time with psychosis.

The LEO and OASIS service is designed to meet the goals outlined in the Early Psychosis Declaration,2 the National Health Service (NHS) Plan3 and the Policy Implementation Guide.4 It thus aims to reduce the delays that young people with psychosis experience in accessing good quality evidence-based care, provides intensive follow up for 2 years to maximize their chances of a full recovery to normal functioning, minimize the potential for relapse during the critical first years of their illnesses, and reduce the distress and burden on carers.

The LEO service is now composed of three teams, each focusing on the different phases of the first episode (see Fig. 1) and works closely with the OASIS team, which focuses on those at ultra-high risk of developing psychosis. The LEO Crisis Assessment Team (LEO CAT) is usually the first point of contact in the community and undertakes the initial assessments and engagement. The LEO Unit is the service’s acute inpatient ward based at Lambeth Hospital. It provides most of the hospital-based requirements for first-episode patients during the first 2 years of contact with LEO. The LEO Community Team provides assertive community-based follow up for 2 years for LEO patients who continue to reside in Lambeth. LEO and OASIS’s structure and programmes are modelled closely on those of the Early Psychosis Prevention and Intervention Centre service.

Figure 1.

Configuration of the LEO and OASIS teams.

The LEO and OASIS service has developed in a stepwise manner over the last 6 years, with each team initially funded by service development grants and for the most part now funded by the local NHS Trust. Research and evaluation has been an integral part of the service from the onset and three of its four teams were designed as randomized controlled trials. The service is closely affiliated to the Institute of Psychiatry. An economic evaluation that included LEO service data demonstrated considerable savings within the first 2 years mainly reflecting reductions in hospital bed usage.5 The LEO and OASIS services are also part of a network of 15 early intervention services (London Early Intervention Research Network), which uses a standard clinical audit system of evaluation.6


The borough of Lambeth (area 14 km2) is a multicultural inner-city area (population 266 170) of south London.7 Traditionally it has been one of the more deprived boroughs (see Fig 3) of London with one of the highest national rates of robbery and assault. It is the fifth most densely populated borough in England with a young population (45% aged 20–40 years), the highest national rate of single people and the second lowest rate of marriage. Its population’s demographics have changed considerably over the last three decades. Thirty-five per cent of its population is born outside England and 26% of the borough’s population describes itself as from black minority ethnic groups. Irish and Indian/Asian migrants (5%) are the most established historically, followed by African Caribbean (12.1% population), then African (11%) and most recently eastern European migrants.

Figure 3.

Incidence of psychosis in Lambeth and Lambeth social deprivation.


South London is well recognized as having one of the highest rates of psychosis in the UK.8 The reported incidence of psychosis in south London has doubled since 19709 with rates of 40 per 100 000 in Lambeth at the beginning of this decade.10,11 There is considerable variation in the age-specific incidence within the borough (Fig. 2) possibly mirroring the extent of deprivation in these areas. Social factors such as social isolation and cohesion/anomie have been implicated by several epidemiologists.8,12

Figure 2.

Incidence of psychosis in Lambeth and Lambeth social deprivation.


Lambeth’s adult mental health services has been through rapid changes in the last decade moving from a rather traditional hospital and clinic-based structure to a more responsive community-based structure. It has a wide range of comprehensive specialist services including rehabilitation, forensic and perinatal services. It has introduced considerable improvements in fiscal management during this time, almost ceasing its reliance on the private sector. However, its budget in 2006 has been cut by 4% by the Primary Care Trust creating further pressure to exact service and financial efficiencies.


In 1997, serious shortcomings in existing services for young people with first-episode psychosis were identified by an internally commissioned report in Lambeth called ‘Bridging the Gap’. This was followed by a study that further highlighted these difficulties and examined the feasibility of establishing an early intervention service in Lambeth.10 These reviews and the increasing international evidence in favour of early intervention provided the impetus to set up a new team, the LEO Community Team, as an assertive follow-up service for people with first-episode psychosis. This team was to be evaluated for the first 2 years as a randomized controlled trial.13


The LEO Community Team began operation in January 2000 as an extended hours 7 days a week service with 10 staff (team leader, part-time consultants, half-time clinical psychologist, trainee psychiatrist, six care coordinators, vocational worker, two health care assistants, and administrator/ receptionist) from a small clinic near central Brixton. It provided intensive case management with a range of psychosocial interventions focusing on recovery and relapse prevention with caseloads of 12–15 clients per case manager. The first 144 clients meeting the criteria for first-episode non-affective psychosis were recruited into the LEO trial14,15 with 71 randomized to follow up by the LEO Community Team and the other 73 to follow up by the local generic services. Follow-up ratings at 18 months revealed that those attending the LEO service were significantly more likely to remain engaged, less likely to relapse (30% vs. 48%) or be rehospitalized14 and had better psychosocial outcomes.15

The team has since been incorporated into mainstream services and continues to date in much the same form though the criteria changed in 2002 to accept cases of all psychosis with a reduction in the upper age limit from 40 to 35 years old. There have also been significant improvements in the range of interventions provided with more medical, vocational and psychology staff input. Specific interventions include cognitive behavioural therapy for psychosis, on-site vocational service, group interventions, and carer support and psychoeducation groups. The hours of operation have reduced to 9 a.m.–6 p.m. Monday–Saturday and caseloads have crept up to 20 patients per care coordinator.

A large amount of effort in the second year of a patient’s follow up is put into planning discharge, future goals, relapse prevention and contingencies in the event of relapse. A developmental ‘timeline’ is drawn up with each patient and a relapse prevention plan worked through before being recorded in a transfer summary. This is then handed over to the follow-up service or general practitioner (GP) in a joint meeting at the point of discharge from the LEO service.


As the LEO Community Team was being established a new acute 18-bed adult inpatient unit was commissioned at Lambeth Hospital to reduce the borough’s reliance on private sector beds. Given the concerns about admitting young first-episode patients to existing acute adult wards, the new unit was to prioritize first-episode patients and those who relapse while being followed up by the LEO Community Team. The new unit opened in March 2001 as an open acute inpatient unit staffed by a multidisciplinary team of 28 (team leader, part-time consultant psychiatrists, 22 nurses and nurses assistants, two junior trainee psychiatrists, half-time clinical psychologist, half-time occupational therapist, administrator). The consultants work across the other LEO teams to provide continuity of care. The ward is L-shaped with segregated gender areas at opposite ends (10 male and 8 female beds) joining as a communal day activity area in the middle. It is funded on a standard adult funding profile with five nurses on daytime shifts and four at night.

The LEO Unit aims to provide a youth-friendly atmosphere that is safe, collaborative and therapeutic. The focus is on psychosocial interventions, low-dose medication and collaborative engagement with clients and carers in treatment decisions. A weekday group programme provides a mix of activity and cognitive oriented groups to address recovery and relapse prevention issues. Every effort is made to manage acutely disturbed patients on close observations on the unit but it does rely on the nearby adult psychiatric intensive care unit (PICU) for managing extremely physically disturbed patients (approximately 5% of LEO inpatients spend part of their admission in PICU).

To date the LEO Unit has had 1425 admissions, of which only a third are first-episode/LEO patients. The remainder are patients who cannot be accommodated on other wards because of bed pressures and who often stay until beds become available on their sector ward. There is an attempt to prioritize younger patients in the earlier years of their illness, although this has not always been possible, and represents a significant extra demand on the unit/service’s resources. Proposals have been made to lease at least six of the 18 LEO unit beds to early intervention services in neighbouring boroughs. This would make for a more sensible use of the unit’s beds within the Trust.


During the initial 2 years of the LEO service, early detection strategies were very limited and the long duration of untreated psychosis (DUP) of newly presenting patients remained a particular concern. In order to address this, a proposal was developed for an early detection team (LEO CAT) to target GPs, improve their detection and referral rates, and provide quick access to LEO CAT for community-based assessments and engagement into the LEO service. Two years funding was granted by the Guy’s and St Thomas’s Charity for LEO CAT and its evaluation. The evaluation was set up as a cluster randomized trial of GP education plus direct access to LEO CAT with control GP practices continuing to refer via generic services. LEO CAT commenced operation in October 2002 and the trial started in June 2003. Results from the trial (n=150) confirm the benefits of such a team on increasing the proportion of first-episode patients referred by GPs, reducing the delays in those referrals, their assessment by mental health services and shortening the time to starting treatment.16 An 18-month follow-up study is near completion with preliminary results that are very comparable to those reported in the original LEO Trial cohort.17

LEO CAT is a small multidisciplinary team (part-time consultant, part-time team leader, junior trainee psychiatrist, psychologist, three nursing staff and an administrator). It operates a weekday 9–5 p.m. service from the same team base as OASIS. It closely links with referring agencies and conducts rapid assessments often at patients’ homes. These assessments are intensive, require considerable engagement and clinical assessment skills, and rely on a crisis intervention/home treatment approach. Once the assessment has been completed and clients engaged in initial treatment LEO CAT hands over to the LEO Community Team for follow up during the recovery phase.


OASIS manages people at ultra-high risk of psychosis, rather than those with a first-episode psychosis. The team was set up in 2001 by Professor Philip McGuire and operates as a weekday 9–5 p.m. service. It started in Lambeth and has since extended to cover the other boroughs within the South London and Maudsley NHS Trust (population 1 million). In Lambeth it works closely with LEO, operating from the same team base, sharing in the early detection strategies, and conducting joint assessments. OASIS provides assessment and follow up for 2 years to people aged 14–35 years meeting the Personal Assessment Crisis Evaluation (PACE) criteria for the At Risk Mental State.18 Interventions include cognitive behavioural therapy and pharmacotherapy, which are currently being evaluated in a clinical trial, plus case management.


Within Lambeth over the past 4 years, OASIS received 292 referrals (69% of the total number of referrals to OASIS from within the Trust) from a wide range of sources in Lambeth including GPs, college counsellors, families and patients, LEO and other mental health teams. Those who met criteria for an ‘At Risk Mental State’ were offered follow up by OASIS. Their mean age at referral was 24.1 years (standard deviation (SD)=4.5) and 53.8% were men. The majority of clients were born in the UK (68.8%). Thirty-six per cent of clients were of black minority ethnicity, 30% white British, 16.3% other white, 6.3% Asian, 2.5% Arab and 8.8% mixed race. The engagement with OASIS was good, and the majority (85%) of clients remained well engaged with the service. Patients who subsequently made a transition to psychosis were promptly transferred to the LEO CAT team. Their mean DUP was 11 days.


The characteristics of first-episode psychosis patients presenting to LEO since the introduction of all components of service are that 71.6% are men, mean age is 24.6 years (SD=5.1). Men are significantly younger at first presentation (mean age men=23.9 years vs. women=26.1 years, P < 0.01). Fifty-one per cent are black British/African/ Caribbean, 25.1% Caucasian, 7.9% mixed, 4.6% Asian, 10.9%‘other’ and 36% born outside UK. Eighty-eight per cent are single, 25% with children, 78% unemployed and 31% report a history of criminal convictions. Mean DUP in the 2002 samples (n=40) were 35 weeks (SD=43.8, range 1–172).19

In the first 6 years of the LEO service, 963 patients were referred and 578 of these were assessed by LEO CAT as suffering from first-episode psychosis (see Fig. 4). The majority (approximately 70%) of these 578 patients were admitted to the LEO Unit during their first episode. However, the proportion of these patients who were hospitalized in the first 18 months of contact has dropped in a stepwise manner since the service began (see Fig. 5) from 82% of those in the standard care control arm of the original LEO Trial to 63% of all patients since the LEO CAT Trial. That combined with earlier discharges has resulted in a 33% reduction in LEO Unit bed usage so that now only 12 of its 18 beds on average accommodate first-episode/LEO patients.

Figure 4.

Referrals during the first 6 years of the LEO service (2000–2005).

Figure 5.

Changes (between 2000 and 2005) in hospitalization rates for Lambeth’s first-episode psychosis patients.

The LEO CAT Community Team has followed up 450 of these 578 patients (73 LEO Trial patients were randomized to the local generic services and 55 patients did not meet the formal criteria of residency in Lambeth or first presentation to mental health services). At any given time the LEO Community Team has approximately 150 patients on its caseload and by the end of the first 6 years of operation the team had transferred/discharged 286 of the 450 patients to follow-up services. The type of follow-up service depended on the extent of patients’ recovery and their risk of relapse. Follow-up recommendations/care plans are made for each patient at a team discharge/transfer planning case conference. The details of the follow-up services are outlined in Figure 6.

Figure 6.

Destinations of patients follow up after leaving the LEO service.


The LEO and OASIS teams have developed incrementally over the last 6 years into a comprehensive early intervention service providing most of the mental health service requirements for young people in Lambeth during each of the phases of early psychosis. There is still considerable scope for improvement and many of the interventions have yet to be evaluated fully. However, it is a significant advance over what was provided before. It represents good value for money and client and carer satisfaction with the service are relatively high. The challenge ahead is to enhance its early detection strategies with referrers, to develop stronger links with recovery and support agencies, to make better use of the spare capacity on the LEO Unit, and in particular to integrate more fully with adolescent services.


Special thanks to the Guy’s and St Thomas’s Charity, the King’s Fund and other stakeholders who have very generously supported the development of a number of LEO and OASIS’s programmes. Also thanks to LEO, OASIS and Trust staff whose invaluable contributions have led to this service’s success. Thanks to James Crompton, Lambeth Primary Care Trust, for his help with producing maps of Lambeth. PP, EI, DG are employed by the South London and Maudsley NHS Trust. PMcG, PG, LV and TC are employed by the Institute of Psychiatry.