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Essential elements of an early intervention service for psychosis: the opinions of expert clinicians



Early intervention teams attempt to improve outcome in schizophrenia through earlier detection and the provision of phase-specific treatments. Whilst the number of early intervention teams is growing, there is a lack of clarity over their essential structural and functional elements.


A 'Delphi' exercise was carried out to identify how far there was consensus on the essential elements of early intervention teams in a group of 21 UK expert clinicians. Using published guidelines, an initial list was constructed containing 151 elements from ten categories of team structure and function.


Overall there was expert consensus on the importance of 136 (90%) of these elements. Of the items on which there was consensus, 106 (70.2%) were rated essential, meaning that in their absence the functioning of the team would be severely impaired.


This degree of consensus over essential elements suggests that it is reasonable to define a model for UK early intervention teams, from which a measure of fidelity could be derived.

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Early intervention attempts to improve outcome in schizophrenia through earlier detection of untreated psychosis and provision of effective, phase-specific treatments [1]. Early intervention is usually delivered by a team of clinicians who work exclusively with people who have recently experienced a first episode of psychosis or have presented with prodromal symptoms of psychosis [2]. Over the past decade early intervention teams have been established in the USA, Canada, Australia and several European countries [3]. The UK Department of Health has announced its intention to set up 50 Early Intervention Teams to provide care to all young people with a first episode of psychosis in England [4].

Early intervention teams are specialised multi-disciplinary entities that seek to provide a range of sophisticated interventions to several distinct target populations. Experience with other specialised psychiatric teams shows that teams with similar labels and philosophies often exhibit profound differences in structure and function [5, 6]. To avoid confusion in research and clinical practice, it is essential to be clear about what are the essential elements of an early intervention team, and to develop a standardised way of assessing the degree to which these elements are present in any particular team.

Two sets of UK guidelines have been produced that describe how to set up early intervention teams. These guidelines were produced by the UK Department of Health [7] and Initiative to Reduce the Impact of Schizophrenia (IRIS) [8]. However it is not clear how far these guidelines reflect the consensus of clinicians working in early intervention teams, if such a consensus exists. The present study used a technique known as the Delphi process to elicit and quantify the opinions of a group of expert clinicians working in UK early intervention teams [9]. Similar Delphi exercises have been used to: clarify the concept of relapse in schizophrenia [10]; identify the key components of schizophrenia care [11] and delineate the practice model of a community mental health team [12]. The aim of the study was to determine the extent of expert consensus on the essential structural and functional elements of early intervention teams.


Participants in the Delphi Exercise were senior clinicians (consultant psychiatrists, community psychiatric nurses, psychologists, etc.) who were working in a clinical capacity in early intervention teams in England. The participants were initially identified from a list of clinicians who had registered an interest in early intervention with the Severe Mental Illness Project Team at the Department of Health. Each eligible person on the list was contacted and asked to participate. They were also invited to nominate other eligible clinicians, who were then approached by the research team.

The Delphi process took place in three stages. In stage one a list of structural and functional elements an early intervention teams was extracted from the two sets of UK guidelines by MM and AL. This list was sent to all participants who were asked to add any additional important elements that they felt had been omitted. An 'element' was defined as 'a person, intervention, method of working or style of service organisation that makes an important contribution to improved outcome for patients when incorporated into an early intervention team'. This initial questionnaire was mailed to participants, with reply-paid envelopes enclosed. All the participants' responses to the first questionnaire were reviewed by (MM and AL) in order to identify elements that needed to be added to the initial list. All new elements suggested by the participants were included except for obvious duplicates or elements that referred to general aspects of good practice which any clinician would be expected to demonstrate, whether or not they worked in an early intervention team (for example, "being polite to service users").

For stage two of the Delphi exercise a questionnaire was constructed containing all the elements identified in stage one. Participants were asked to rate the importance of each element on a 1 to 5 scale. The scale anchor points were: 1 – essential (without this element the effective functioning of the team would be severely impaired); 2 – very important (without this element the team would be less effective, but not severely impaired); 3 – important (this element desirable, but its absence would not make the team noticeably less effective for most service users); 4 – unimportant (absence of this element would have little impact on effectiveness); 5 undesirable (presence of this element would have a detrimental effect on effectiveness). The questionnaire was mailed to each participating expert. The responses were entered on a database which was used to produce a customised questionnaire for each expert in stage three of the study.

Stage three of the exercise used the same questionnaire as stage two, with the addition of two extra pieces of information for each element. The first piece of information was that the expert's previous rating was indicated by underlining the relevant anchor point. The second piece of information was the level of agreement within the group of experts as a whole was indicated by shading each score within one point of the median rating for each item (for example, if the median rating for a particular element was 2, then the ratings 1, 2 and 3 would be shaded). Each expert was asked to reconsider their original ratings from stage 2 in the light of this new information. If their new rating was outside the shaded area (indicating that they disagreed with the rest of the panel), they were asked to comment on their reasons for making the rating. The degree of consensus was assessed by calculating the interquartile range of the participants' ratings of importance [13, 14]. A semi-interquartile range of 0.5 or less was interpreted as indicating consensus.

Results and Discussion

Forty-eight potential participants were identified (32 from the initial list and a further 16 suggested by people on the list). It was possible to contact 41 of the 48 potential participants, of whom 16 did not meet inclusion criteria (they were not currently working in an early intervention team) and 4 declined to participate. Of the 21 clinicians who participated, 7 were psychiatrists, 9 were community psychiatric nurses, and 5 were clinical psychologists. The mean age of participants was 42.2 yrs (95% CI 38.2–46.2) and they had been working in early intervention services for a mean of 4.3 yrs (95% CI 3.0–5.5). Thirteen participants were based in urban areas and eight in rural areas. The participants came from a total of eleven English early intervention teams with catchment areas ranging from 50,000 to 500,000 (median 160,000). The team sizes ranged from 2 to 35 members with a median of 6.5.

There were 100 key elements on the initial list generated from the two sets of guidelines. Responses were received from all 21 participants, 15 of whom suggested a total of 71 additional elements. Of these new elements, 11 were excluded because they were considered to be duplications of elements already included in the initial list and a further 9 were excluded because they were considered to be general statements of good psychiatric practice, rather than elements specific to an early intervention team. Therefore at the end of stage one the final list consisted of 151 elements. These elements fell into 10 broad categories: the client group (11 elements), team structure and ethos (10), membership of the team (15), referral and assessment procedures (34), engaging and maintaining contact (10), non-pharmaceutical interventions (23), pharmaceutical interventions (15), relatives and significant others (12), admission to hospital or crisis care (10) and community connections (11).

All 21 experts returned the completed stage two and stage three questionnaires. The experts made few alterations to their opinions in stage three. Tables 1, 2, 3, 4, 5 group the elements according to the median rating and degree of consensus as measured by the semi-interquartile range (0–0.25 strong consensus, 0.25–0.5 good consensus, greater than 0.5 weak consensus). Fifty-two items were rated essential with strong consensus (table 1); 54 items were rated essential with good consensus (table 2); 25 items were very important with good consensus (table 3.); 12 items were rated very important with weak consensus; 4 items were rated important with good consensus; 2 items were rated important with weak consensus; 1 item was rated not important with weak consensus. Only one item was rated as undesirable, this item had good consensus. Thus overall strong or good consensus was present for 136 (90%) elements, of which 106 (70.2%) were rated essential. Items proposed by a participating clinician were significantly less likely to be rated essential or very important (odds ratio 0.15, 95% CI 0.015–0.90, p = 0.018), however they were not significantly more likely to fail to achieve consensus (odds ratio 2.47 95% CIs 0.73–8.52 p = 0.15), although confidence intervals for this odds ratio were wide.

Table 1 Elements rated essential with strong consensus
Table 2 Elements rated essential with good consensus
Table 3 Elements rated very important with good consensus
Table 4 Elements rated very important with weak consensus
Table 5 Other elements


This study has highlighted the complexity of early intervention teams by showing that it was possible to identify 151 distinct structural and functional elements of such teams using two sets of guidelines and the opinions of twenty-one expert clinicians. There was high degree of consensus amongst expert clinicians that about two thirds of these elements (106) were essential. By way of comparison, a similar exercise conducted with clinical experts in assertive outreach identified 73 elements, of which 54 (74%) were rated very important [15]. Thus, in the judgement of clinical experts, an early intervention team appeared to be considerably more complex that an assertive outreach team, which in itself is an entity of some intricacy.

The present consensus over the essential elements of early intervention teams suggests that it is reasonable to define a model for UK teams, from which a measure of fidelity could be derived. Such a measure will be essential if research on early intervention is not to be clouded by controversy over how far the model was properly implemented in particular studies. It will also be essential in clinical practice to evaluate the degree to which a team with the early intervention "label" is actually adhering to the specifics of the model.

The consensus between clinical experts suggests that the existing UK guidelines, from which about two thirds of the elements were derived, are generally accepted. It could be argued that this was because the initial list of clinicians was provided by the Department of Health, who also endorsed the guidelines. However, one third of the experts approached were not on the original list, and the final sample included clinicians from eleven different teams and four different professions, which suggests that a reasonable range of opinion was canvassed. A more likely explanation for the consensus is that there was insufficient evidence available on the effectiveness of different approaches to early intervention for the clinicians to be confident in ruling out any particular element. However, clinicians were united on the undesirability of one element: they agreed that early intervention teams should be free standing teams, and not an additional function of existing community mental health teams.

It would be interesting to repeat this exercise with an international panel of experts to make the results more applicable to a global audience.


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The research was supported by a grant from the Department of Health.

The authors would like to thank all the clinicians who agreed to take part in the Delphi exercise.

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Correspondence to Max Marshall.

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Authors' contributions

MM: Analysed the results and prepared the manuscript

AL: Contacted participants, collected data and assisted in the preparation of the manuscript

MF: Designed the study and acted as consultant on the Delphi methodology

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Marshall, M., Lockwood, A., Lewis, S. et al. Essential elements of an early intervention service for psychosis: the opinions of expert clinicians. BMC Psychiatry 4, 17 (2004).

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