Early intervention in psychosis
Early intervention in psychosis is a clinical approach to those experiencing symptoms of psychosis for the first time. It forms part of a new prevention paradigm for psychiatry and is leading to reform of mental health services, especially in the United Kingdom  and Australia.
This approach centers on the early detection and treatment of early symptoms of psychosis during the formative years of the psychotic condition. The first three to five years are believed by some to be a critical period. The aim is to reduce the usual delays to treatment for those in their first episode of psychosis. The provision of optimal treatments in these early years is thought to prevent relapses and reduce the long-term impact of the condition. It is considered a secondary prevention strategy.
Components of the model
There are a number of functional components of the early psychosis model, and they can be structured as different sub-teams within early psychosis services. The emerging pattern of sub-teams are currently:
Early psychosis treatment teams
Multidisciplinary clinical teams providing an intensive case management approach for the first three to five years. The approach is similar to assertive community treatment, but with an increased focus on the engagement and treatment of this previously untreated population and the provision of evidence based, optimal interventions for clients in their first episode of psychosis. For example, the use of low-dose antipsychotic medication is promoted ("start low, go slow"), with a need for monitoring of side effects and an intensive and deliberate period of psycho-education for patients and families that are new to the mental health system. In addition, researchers in Spain showed that family intervention for psychosis (FIp) reduced relapse rates, hospitalization duration, and psychotic symptoms along with increasing functionality in first-episode psychosis (FEP) up to 24 months, according to a recent review published in Schizophrenia Bulletin. Interventions to prevent a further episodes of psychosis (a "relapse") and strategies that encourage a return to normal vocation and social activity are a priority. There is a concept of phase specific treatment for acute, early recovery and late recovery periods in the first episode of psychosis.
Early detection function
Interventions aimed at avoiding late detection and engagement of those in the course of their psychotic conditions. Key tasks include being aware of early signs of psychosis and improving pathways into treatment. Teams provide information and education to the general public and assist GPs with recognition and response to those with suspected signs, for example: EPPIC's Youth Access Team (YAT) (Melbourne); OPUS (Denmark); TIPS (Norway); REDIRECT (Birmingham); LEO CAT (London) "; STEP's Population Health approach to early detection.
The development and implementation of quantitative tools for early detection of at-risk individuals is an active research area. This includes development of risk calculators and methods for large-scale population screening.
Prodrome or at risk mental state clinics are specialist services for those with subclinical symptoms of psychosis or other indicators of risk of transition to psychosis. The Pace Clinic in Melbourne, Australia, is considered one of the origins of this strategy, but a number of other services and research centers have since developed.  These services are able to reliably identify those at high risk of developing psychosis and are beginning to publish encouraging outcomes from randomised controlled trials that reduce the chances of becoming psychotic, including evidence that psychological therapy and high doses of fish oil have a role in the prevention of psychosis. However, a meta-analysis of five trials found that while these interventions reduced risk of psychosis after 1 year (11% conversion to psychosis in intervention groups compared to 32% in control groups), these gains were not maintained over 2–3 years of follow-up. These findings indicate that interventions delay psychosis, but do not reduce the long-term risk. There has also been debate about the ethics of using antipsychotic medication to reduce the risk of developing psychosis, because of the potential harms involved with these medications.
In 2015, the European Psychiatric Association issued guidance recommending the use of the Cognitive Disturbances scale (COGDIS), a subscale of the basic symptoms scale, to assess psychosis risk; a meta-analysis conducted for the guidance found that while rates of conversion to psychosis were similar to those who meet Ultra High Risk (UHR) criteria up to 2 years after assessment, they were significantly higher after 2 years for those patients who met the COGDIS criteria. The COGDIS criteria measure subjective symptoms, and include such symptoms as thought interference, where irrelevant and emotionally unimportant thought contents interfere with the main line of thinking; thought block, where the current train of thought halts; thought pressure, where thoughts unrelated to a common topic appear uncontrollably; referential ideation that is immediately corrected; and other characteristic disturbances of attention and the use or understanding of language.
Early intervention in psychosis is a preventive approach for psychosis that has evolved as contemporary recovery views of psychosis and schizophrenia have gained acceptance. It subscribes to a "post Kraepelin" concept of schizophrenia, challenging the assumptions originally promoted by Emil Kraepelin in the 19th century, that schizophrenia ("dementia praecox") was a condition with a progressing and deteriorating course. The work of Post, whose kindling model, together with Fava and Kellner, who first adapted staging models to mental health, provided an intellectual foundation. Psychosis is now formulated within a diathesis–stress model, allowing a more hopeful view of prognosis, and expects full recovery for those with early emerging psychotic symptoms. It is more aligned with psychosis as continuum (such as with the concept of schizotypy) with multiple contributing factors, rather than schizophrenia as simply a neurobiological disease.
Within this changing view of psychosis and schizophrenia, the model has developed from a divergence of several different ideas, and from a number of sites, beginning with the closure of psychiatric institutions signaling a move toward community based care. In 1986, the Northwick Park study discovered an association between delays to treatment and disability, questioning the service provision for those with their first episode of schizophrenia. In the 1990s, evidence began to emerge that cognitive behavioural therapy was an effective treatment for delusions and hallucinations. The next step came with the development of the EPPIC early detection service in Melbourne, Australia in 1996 and the prodrome clinic led by Alison Yung. This service was an inspiration to other services, such as the West Midlands IRIS group, including the carer charity Rethink Mental Illness; the TIPS early detection randomised control trial in Norway; and the Danish OPUS trial. In 2001, the United Kingdom Department of Health called the development of early psychosis teams "a priority". The International Early Psychosis Association, founded in 1998, issued an international consensus declaration together with the World Health Organization in 2004. Clinical practice guidelines have been written by consensus.
Clinical outcome evidence
A number of studies have been carried out to see whether the early psychosis approach reduces the severity of symptoms, improves relapse rates, and decreases the use of inpatient care, in comparison to standard care. Advocates of early intervention for psychosis have been accused of selectively citing findings that support the benefits of early intervention, but ignoring findings that do not. It has been argued that the scientific reporting of evidence on early intervention in psychosis is characterized by a high prevalence of ‘spin’ and ‘bias’. An analysis of the summaries of articles found that 75% implied positive results, whereas examination of the findings with primary measures from these studies found that only 13% were positive. A systematic review investigated the effects of early intervention for psychosis:
|There is emerging, but as yet inconclusive evidence, to suggest that people in the prodrome of psychosis can be helped by some interventions. There is some support for specialized early intervention services, but further trials would be desirable, and there is a question of whether gains are maintained. There is some support for phase-specific treatment focused on employment and family therapy, but again, this needs replicating with larger and longer trials.|
Evidence on cost
Studies have been published claiming that early psychosis services cost less than standard services, largely through reduced in-patient costs, and also save other costs to society. However, the claimed savings have been disputed. A 2012 systematic review of the evidence concluded that: "The published literature does not support the contention that early intervention for psychosis reduces costs or achieves cost-effectiveness".
Reform of mental health services
The United Kingdom has made significant service reform with their adoption of early psychosis teams following the first service in Birmingham set up by Professor Max Birchwood in 1994 and used as a blueprint for national roll-out, with early psychosis now considered as an integral part of comprehensive community mental health services. The Mental Health Policy Implementation Guide outlines service specifications and forms the basis of a newly developed fidelity tool. There is a requirement for services to reduce the duration of untreated psychosis, as this has been shown to be associated with better long-term outcomes. The implementation guideline recommends:
- 14 to 35 year age entry criteria
- First three years of psychotic illness
- Aim to reduce the duration of untreated psychosis to less than 3 months
- Maximum caseload ratio of 1 care coordinator to 10–15 clients
- For every 250,000 (depending on population characteristics), one team
- Total caseload 120 to 150
- 1.5 doctors per team
- Other specialist staff to provide specific evidence based interventions
Australia and New Zealand
In Australia the EPPIC initiative provides early intervention services. In the Australian government's 2011 budget, $222.4 million was provided to fund 12 new EPPIC centres in collaboration with the states and territories. However, there have been criticisms of the evidence base for this expansion and of the claimed cost savings.
On August 19, 2011, Patrick McGorry, South Australian Social Inclusion Commissioner David Cappo AO and Frank Quinlan, CEO of the Mental Health Council of Australia, addressed a meeting of the Council of Australian Governments (COAG), chaired by Prime Minister Julia Gillard, on the future direction of mental health policy and the need for priority funding for early intervention. The invitation, an initiative of South Australian Premier Mike Rann, followed the release of Cappo's "Stepping Up" report, supported by the Rann Government, which recommended a major overhaul of mental health in South Australia, including stepped levels of care and early intervention.
New Zealand has operated significant early psychosis teams for more than 20 years, following the inclusion of early psychosis in a mental health policy document in 1997. There is a national early psychosis professional group, New Zealand Early Intervention for Psychosis Society (NZEIPS), organising a biannual training event, advocating for evidenced based service reform and supporting production of local resources.
Canada has extensive coverage across most provinces, including established clinical services and comprehensive academic research in British Columbia (Vancouver), Alberta (EPT in Calgary), Quebec (PEPP-Montreal), and Ontario (PEPP, FEPP).
In the United States, the Early Assessment Support Alliance (EASA) is implementing early psychosis intervention throughout the state of Oregon.
In the United States, the implementation of Coordinated Specialty Care (CSC), as a recovery-oriented treatment program for people with first episode psychosis (FEP), has become a US health policy priority. CSC promotes shared decision making and uses a team of specialists who work with the client to create a personal treatment plan. The specialists offer psychotherapy, medication management geared to individuals with FEP, family education and support, case management, and work or education support, depending on the individual's needs and preferences. The client and the team work together to make treatment decisions, involving family members as much as possible. The goal is to link the individual with a CSC team as soon as possible after psychotic symptoms begin because a longer period of unchecked and untreated illness might be associated with poorer outcomes.
- McGorry PD, Killackey EJ (2002). "Early intervention in psychosis: a new evidence based paradigm". Epidemiol Psychiatr Sci. 11 (4): 237–47. doi:10.1017/s1121189x00005807. PMID 12585014.
- McGorry PD, Killackey E, Yung A (October 2008). "Early intervention in psychosis: concepts, evidence and future directions". World Psychiatry. 7 (3): 148–56. doi:10.1002/j.2051-5545.2008.tb00182.x. PMC 2559918. PMID 18836582.
- Killackey E, Yung AR, McGorry PD (2007). "Early psychosis: where we've been, where we still have to go". Epidemiol Psychiatr Sci. 16 (2): 102–8. doi:10.1017/S1121189X0000470X. PMID 17619539.
- "IRIS History of the development of EI in the UK". Archived from the original on 2012-08-03. Retrieved 2009-12-04.
- Joseph R, Birchwood M (September 2005). "The national policy reforms for mental health services and the story of early intervention services in the United Kingdom" (PDF). J Psychiatry Neurosci. 30 (5): 362–5. PMC 1197282. PMID 16151542. Archived from the original (PDF) on 2015-11-17. Retrieved 2009-02-28.
- Birchwood M; Tood P; Jackson C (1988). "Early intervention in psychosis: the critical period hypothesis". British Journal of Psychiatry. Supplement 33 (33): 53–59. doi:10.1192/S0007125000297663. PMID 9764127. S2CID 32411917.
- Marshall M; Lewis S; Lockwood A; Drake R; Jones P; Croudace T (2005). "Association between duration of untreated psychosis and outcome in cohorts of first-episode patients: a systematic review". Arch Gen Psychiatry. 62 (9): 975–983. doi:10.1001/archpsyc.62.9.975. PMID 16143729.
- Edwards, J. & McGorry, P.D. (2002) (eds). Implementing Early Intervention in Psychosis. A guide to establishing early psychotic services. London. Martin Dunitz.
- International Early Psychosis Association Writing Group (2005). "International clinical practice guidelines for early psychosis". British Journal of Psychiatry. Supplement 48: s120–s124. doi:10.1192/bjp.187.48.s120. PMID 16055801.
- Marshall M; Lockwood A; Lewis S; Fiander M (2004). "Essential elements of an early intervention service for psychosis: the opinions of expert clinicians". BMC Psychiatry. 4: 17. doi:10.1186/1471-244X-4-17. PMC 455683. PMID 15230978.
- Camacho-Gomez M, Castellvi P. Effectiveness of family intervention for preventing relapse in first-episode psychosis until 24 months of follow-up: a systematic review with meta-analysis of randomized controlled trials [published online May 3, 2019]. Schizophr Bull. doi: https://doi.org/10.1093/schbul/sbz038
- Larsen TK; Friis S; Haahr U; Joa I; Johannessen JO; Melle I; Opjordsmoen S; Simonsen E; Vaglum P (2001). "Early detection and intervention in first-episode schizophrenia: a critical review". Acta Psychiatrica Scandinavica. 103 (5): 323–334. doi:10.1034/j.1600-0447.2001.00131.x. PMID 11380302.
- Johannessen JO, McGlashan TH, Larsen TK, et al. (August 2001). "Early detection strategies for untreated first-episode psychosis". Schizophr. Res. 51 (1): 39–46. doi:10.1016/S0920-9964(01)00237-7. PMID 11479064. S2CID 7361138.
- McGorry PD; Edwards J; Mihalopoulos C; Harrigan SM; Jackson HJ (1996). "EPPIC: an evolving system of early detection and optimal management". Schizophrenia Bulletin. 22 (2): 305–326. doi:10.1093/schbul/22.2.305. PMID 8782288. Retrieved 2009-02-14.
- "Youth Access Team (YAT) Staff". Archived from the original on February 25, 2010. Retrieved 2009-02-14.
- Petersen L; Nordentoft M; Jeppesen P; Ohlenschaeger J; Thorup A; Christensen TØ; Krarup G; Dahlstrøm J; Haastrup B; Jørgensen P (2005). "Improving 1-year outcome in first-episode psychosis: OPUS trial". British Journal of Psychiatry. 187 (Supplement 48): s98–s103. doi:10.1192/bjp.187.48.s98. PMID 16055817.
- "TIPS webpage". Retrieved 2009-02-14.
- Tait L; Lester H; Birchwood M; Freemantle N; Wilson S (2005). "Design of the BiRmingham Early Detection In untREated psyChosis Trial (REDIRECT): cluster randomised controlled trial of general practitioner education in detection of first episode psychosis [ISRCTN87898421]". BMC Health Services Research. 5 (1): 19. doi:10.1186/1472-6963-5-19. PMC 1082907. PMID 15755321.
- Power P; Iacoponi E; Reynolds N; Fisher H; Russell M; Garety P; McGuire PK; Craig T (2007). "The Lambeth Early Onset Crisis Assessment Team Study: general practitioner education and access to an early detection team in first-episode psychosis". British Journal of Psychiatry. Supplement 51: s133–s139. doi:10.1192/bjp.191.51.s133. PMID 18055931.
- Srihari, Vinod H.; Jani, Anant; Gray, Muir (2016-02-01). "Early Intervention for Psychotic Disorders". JAMA Psychiatry. 73 (2): 101–2. doi:10.1001/jamapsychiatry.2015.2821. ISSN 2168-622X. PMID 26747524.
- Srihari, Vinod H.; Tek, Cenk; Pollard, Jessica; Zimmet, Suzannah; Keat, Jane; Cahill, John D.; Kucukgoncu, Suat; Walsh, Barbara C.; Li, Fangyong (2014-12-04). "Reducing the duration of untreated psychosis and its impact in the U.S.: the STEP-ED study". BMC Psychiatry. 14: 335. doi:10.1186/s12888-014-0335-3. ISSN 1471-244X. PMC 4262386. PMID 25471062.
- Fusar-Poli, P, Rutigliano, G, Stahl, D, Davies, C, Bonoldi, I, Reilly, T, McGuire, P (2017). "Development and validation of a clinically based risk calculator for the transdiagnostic prediction of psychosis". JAMA Psychiatry. 74 (5): 493–500. doi:10.1001/jamapsychiatry.2017.0284. PMC 5470394. PMID 28355424.}
- Raket LL, Jaskolowski J, Kinon BJ, Brasen JC, Jönsson L, Wehnert A, Fusar-Poli P (2020). "Dynamic ElecTronic hEalth reCord deTection (DETECT) of individuals at risk of a first episode of psychosis: a case-control development and validation study". The Lancet Digital Health. 2 (5): e229–e239. doi:10.1016/S2589-7500(20)30024-8.
- "Archived copy". Archived from the original on 2009-10-24. Retrieved 2009-02-20.CS1 maint: archived copy as title (link)
- Yung AR, McGorry PD, McFarlane CA, Jackson HJ, Patton GC, Rakkar A (1996). "Monitoring and care of young people at incipient risk of psychosis". Schizophr Bull. 22 (2): 283–303. doi:10.1093/schbul/22.2.283. PMID 8782287.
- Broome MR, Woolley JB, Johns LC, et al. (August 2005). "Outreach and support in south London (OASIS): implementation of a clinical service for prodromal psychosis and the at risk mental state". Eur. Psychiatry. 20 (5–6): 372–8. doi:10.1016/j.eurpsy.2005.03.001. PMID 16171652.
- Yale Medical School based clinic | PRIME
- Yung AR, Phillips LJ, Yuen HP, et al. (March 2003). "Psychosis prediction: 12-month follow up of a high-risk ("prodromal") group". Schizophr. Res. 60 (1): 21–32. doi:10.1016/S0920-9964(02)00167-6. PMID 12505135. S2CID 31342026.
- McGorry PD, Yung AR, Phillips LJ, et al. (October 2002). "Randomized controlled trial of interventions designed to reduce the risk of progression to first-episode psychosis in a clinical sample with subthreshold symptoms". Arch. Gen. Psychiatry. 59 (10): 921–8. doi:10.1001/archpsyc.59.10.921. PMID 12365879.[permanent dead link]
- Morrison AP, French P, Parker S, et al. (May 2007). "Three-year follow-up of a randomized controlled trial of cognitive therapy for the prevention of psychosis in people at ultrahigh risk". Schizophr Bull. 33 (3): 682–7. doi:10.1093/schbul/sbl042. PMC 2526150. PMID 16973786.
- Amminger; Schäfer; Papageorgiou; Harrigan; Cotton; McGorry; Berger (2008). "Indicated Prevention of Psychotic Disorders with Long-Chainomega-3 Fatty Acids: A Randomized, Placebo-Controlled Trial". Schizophrenia Research. 102 (1–3): 252. doi:10.1016/s0920-9964(08)70758-8. S2CID 53301111.
- Preti A, Cella M (2010). "Randomized-controlled trials in people at ultra high risk of psychosis: a review of treatment effectiveness". Schizophrenia Research. 123 (1): 30–36. doi:10.1016/j.schres.2010.07.026. PMID 20727717. S2CID 28017135.
- Jorm AF (2012). "Ethics of giving antipsychotic medication to at-risk young people". Australian and New Zealand Journal of Psychiatry. 46 (9): 908–909. doi:10.1177/0004867412455233. PMID 22802552. S2CID 206398433.
- Schultze-Lutter, F.; Michel, C.; Schmidt, S.J.; Schimmelmann, B.G.; Maric, N.P.; Salokangas, R.K.R.; Riecher-Rössler, A.; van der Gaag, M.; Nordentoft, M.; Raballo, A.; Meneghelli, A.; Marshall, M.; Morrison, A.; Ruhrmann, S.; Klosterkötter, J. (2015). "EPA guidance on the early detection of clinical high risk states of psychoses". European Psychiatry. 30 (3): 405–416. doi:10.1016/j.eurpsy.2015.01.010. ISSN 0924-9338. PMID 25735810.
- Falloon I.R. (1992). "Early intervention for first episodes of schizophrenia: A preliminary exploration". Psychiatry. 55 (1): 4–15. doi:10.1080/00332747.1992.11024572. PMID 1557469.
- Johnstone EC; Crow TJ; Johnson AL; MacMillan JF (1986). "The Northwick Park Study of first episodes of schizophrenia. I. Presentation of the illness and problems relating to admission". British Journal of Psychiatry. 148 (2): 115–120. doi:10.1192/bjp.148.2.115. PMID 3697578.
- Sensky T, Turkington D, Kingdon D, Scott JL, Scott J, Siddle R, O'Carroll M, Barnes TR (February 2000). "A randomized controlled trial of cognitive-behavioral therapy for persistent symptoms in schizophrenia resistant to medication". Arch. Gen. Psychiatry. 57 (2): 165–72. doi:10.1001/archpsyc.57.2.165. PMID 10665619.
- Kuipers E, Garety P, Fowler D, Dunn G, Bebbington P, Freeman D, Hadley C (October 1997). "London-East Anglia randomised controlled trial of cognitive-behavioural therapy for psychosis. I: effects of the treatment phase". Br J Psychiatry. 171 (4): 319–27. doi:10.1192/bjp.171.4.319. PMID 9373419.
- Lewis S, Tarrier N, Haddock G, Bentall R, Kinderman P, Kingdon D, Siddle R, Drake R, Everitt J, Leadley K, Benn A, Grazebrook K, Haley C, Akhtar S, Davies L, Palmer S, Faragher B, Dunn G (September 2002). "Randomised controlled trial of cognitive-behavioural therapy in early schizophrenia: acute-phase outcomes". Br J Psychiatry Suppl. 43: s91–7. doi:10.1192/bjp.181.43.s91. PMID 12271807.
- Department of Health. (2001) The mental health policy implementation guide. London: Department of Health.
- "Early Psychosis Declaration: An International Consensus Statement about Early Intervention and Recovery for Young People with Early Psychosis. Jointly issued by the World Health Organization and International Early Psychosis Association" (PDF). 28 September 2004.
- Bertolote J; McGorry P (2005). "Early intervention and recovery for young people with early psychosis: consensus statement". British Journal of Psychiatry. Supplement 48: s116–s119. doi:10.1192/bjp.187.48.s116. PMID 16055800.
- Amos A (2013). "An axeman in the cherry orchard: early intervention rhetoric distorts public policy". Australian and New Zealand Journal of Psychiatry. 47 (4): 317–320. doi:10.1177/0004867412471438. PMID 23568159. S2CID 8198295. (subscription required)
- Amos A (2014). "A review of spin and bias use in the early intervention in psychosis literature". The Primary Care Companion for CNS Disorders. 16 (1): PCC.13r01586. doi:10.4088/PCC.13r01586. PMC 4048144. PMID 24940528.
- Marshall, M; Rathbone, J (2011). "Early intervention for psychosis". Cochrane Database of Systematic Reviews. 6 (6): 1111–1114. doi:10.1002/14651858.CD004718.pub3. PMC 4163966. PMID 21678345.
- McCrone, P.; Knapp, M.; Dhanasiri, S. (2009). "Economic impact of services for first-episode psychosis: a decision model approach". Early Intervention in Psychiatry. 3 (4): 266–273. doi:10.1111/j.1751-7893.2009.00145.x. PMID 22642729.
- Mihalopoulos C, McGorry PD, Carter RC (July 1999). "Is phase-specific, community-oriented treatment of early psychosis an economically viable method of improving outcome?". Acta Psychiatr Scand. 100 (1): 47–55. doi:10.1111/j.1600-0447.1999.tb10913.x. PMID 10442439.
- Amos A (2012). "Assessing the cost of early intervention in psychosis: a systematic review". Australian and New Zealand Journal of Psychiatry. 46 (8): 719–734. doi:10.1177/0004867412450470. PMID 22696550. S2CID 27598337.
- Birchwood, unpublished.
- "Site disabled | orcmanage.unimelb.edu.au".
- "Archived copy". Archived from the original on 2013-04-24. Retrieved 2013-04-13.CS1 maint: archived copy as title (link)
- Raven M. Evaluating evidence for Early Psychosis Prevention and Intervention Centres (EPPIC). The Conversation 2 Nov 2011 http://theconversation.com/evaluating-evidence-for-early-psychosis-prevention-and-intervention-centres-eppic-3604
- Amos A (2013). "An axeman in the cherry orchard: early intervention rhetoric distorts public policy". Aust N Z J Psychiatry. 47 (4): 317–320. doi:10.1177/0004867412471438. PMID 23568159. S2CID 8198295.
- Jorm AF (2013). "Do early intervention for psychosis services really save money?". Aust N Z J Psychiatry. 47 (4): 396–7. doi:10.1177/0004867412461959. PMID 23015749. S2CID 32272758.
- http://www.coag.gov.au/ "COAG Meeting 19th August 2011
- Center for National Policy, Washington DC; "What States Can Do:Reform Mental Health", August 8, 2012
- Blueprint for mental health service.
- "Oregon Health Authority : Addictions and Mental Health Services : Addictions and Mental Health Services : State of Oregon".
- "What It Will Take to Make Coordinated Specialty Care Available to Anyone Experiencing Early Schizophrenia: Getting Over the Hump". PubMed Journals. Retrieved 2017-09-19.
- "NIMH » What is Coordinated Specialty Care (CSC)?". www.nimh.nih.gov. Retrieved 2017-09-19.
- Harrigan, S. M.; McGorry, P. D.; Krstev, H. (January 2003). "Does treatment delay in first-episode psychosis really matter?". Psychological Medicine. 33 (1): 97–110. doi:10.1017/s003329170200675x. ISSN 0033-2917. PMID 12537041.
- Addington, J.; Van Mastrigt, S.; Addington, D. (February 2004). "Duration of untreated psychosis: impact on 2-year outcome". Psychological Medicine. 34 (2): 277–284. doi:10.1017/s0033291703001156. ISSN 0033-2917. PMID 14982133.
- Wunderink, A.; Nienhuis, F. J.; Sytema, S.; Wiersma, D. (April 2006). "Treatment delay and response rate in first episode psychosis". Acta Psychiatrica Scandinavica. 113 (4): 332–339. doi:10.1111/j.1600-0447.2005.00685.x. ISSN 0001-690X. PMID 16638078.
- Kane, John M.; Robinson, Delbert G.; Schooler, Nina R.; Mueser, Kim T.; Penn, David L.; Rosenheck, Robert A.; Addington, Jean; Brunette, Mary F.; Correll, Christoph U. (2016-04-01). "Comprehensive Versus Usual Community Care for First-Episode Psychosis: 2-Year Outcomes From the NIMH RAISE Early Treatment Program". The American Journal of Psychiatry. 173 (4): 362–372. doi:10.1176/appi.ajp.2015.15050632. ISSN 1535-7228. PMC 4981493. PMID 26481174.
- "Epip". Epip. Retrieved 2009-02-14.
- "「思覺失調」服務計劃". ha.org.hk. Retrieved 2009-02-14.
- "youth clinic". youthclinic.org. Retrieved 2009-02-14.
- Early Psychosis Prevention and Intervention Centre (EPPIC)
- Rethink: What is Early Intervention (UK)
- Initiative to Reduce Impact of Schizophrenia (IRIS)
- Psychosis sucks, British Columbia, Canada
- TIPS, Stavanger, Norway
- The Recognition and Prevention Program (RAP), Glen Oaks, NY, USA
- Early Assessment and Support Alliance Oregon, USA
- Program for Specialized Treatment Early in Psychosis, STEP New Haven, CT, USA