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Information Australia 2003–2008. Canberra: Commonwealth of Australia. Australian Institute of Health and Welfare (2012) Disability support services: Services provided under the National Disability Agreement 2010–11. Disability Series. Cat. no. DIS 60. Canberra: AIHW. Büscher A, Wingenfeld K and Schaeffer D (2011) Determining eligibility for long-term carelessons from Germany. International Journal of Integrated Care 11: e019. Duffy S and Williams R (2012) The Road to NDIS: Lessons from England about Assessment and Planning. Unley, South Australia: JFA Purple Orange.

European Commission / Statistical Office (Eurostat) (2003) Feasibility study about comparable statistics in the area of care of dependant adults in the European Union. Luxembourg: Office for Official Publications of the European Communities. Ochoa S, Salvador-Carulla L, Vilalta V, et  al. (2012) Use of functioning-disability, and dependency for case-mix and subtyping of schizophrenia. European Journal of Psychiatry 26: 1–12. Salvador-Carulla L, Alvarez-Galvez J, Romero C, et  al. (2013) Evaluation of an integrated system for classification, assessment and comparison of services for long-term care in Europe:

The eDESDE-LTC study. BMC Health Services Research 13: 218. Wakefield JC (2009) Disability and diagnosis: Should role impairment be eliminated from DSM/ICD diagnostic criteria? World Psychiatry 8: 87–88. Whiteford HA, Degenhardt L, Rehm J, et al. (2013) Global burden of disease attributable to mental and substance use disorders: Findings from the Global Burden of Disease Study 2010. Lancet 382: 1575–1586. Williams TM and Smith GP (2014) Can the National Disability Insurance Scheme work for mental health? Australian and New Zealand Journal of Psychiatry 48: 390–393.

Drugs and psychosis … and now for some good news Grant E Sara1,2,3

There is growing evidence to support this claim. A meta-analysis of 23 studies by the same authors (Mullin et  al., 2012) found that former substance users consistently have fewer positive symptoms and better functioning than people with psychosis who do not use substances. These are clinically significant effects; in more than 600 young people with early psychosis (Lambert et al., 2005), reducing substance use was the strongest predictor of remission. After controlling for age, sex, duration of untreated psychosis and symptom severity, decreasing or ceasing substance use more than doubled the likelihood of remission (hazard ratio 2.44). We have recently examined young people with a first psychosis admission in New South Wales. Of 4933 people who remained in contact with services over 2 years, those with ongoing substance problems had the highest readmission rate (66%), those with no substance disorders had an intermediate rate (50%) and those whose substance problems ceased had the lowest readmission rate (40%) (Sara et al., 2014b). A link between substance use (even if discontinued) and positive outcome in psychosis seems counterintuitive. After all, substance use is associated with other factors usually linked to worse outcome in psychosis, including male gender, earlier onset of psychosis, social disadvantage and a family history of mental health and substance problems. Three

explanations have been proposed to account for this apparent link between substance use and positive outcome: (i) direct chemical effects, (ii) social skills and (iii) personal vulnerability. First, it is possible that substances themselves may have direct positive effects on brain function. Yucel and colleagues (2012) summarise evidence that cannabis use in people with psychosis is associated with better cognitive function as well as with fewer psychotic symptoms, leading to suggestions that cannabis may have direct neuro-protective effects or stimulate prefrontal neurotransmission. It is difficult to reconcile this theory with the harmful effects of ongoing cannabis use; however, our understanding of the effects of cannabis continues to evolve. For example, the interaction of THC and cannabidiols with endocannabinoid receptors is likely to involve both harmful and protective effects (Paparelli et al., 2011). Second, Meuser et al. (1998) have proposed that the association of substances with positive outcome in psychosis is mediated through social competence, whereby more ‘socially oriented patients with serious mental illness are more likely to come into contact with drugs and subsequently develop substance use disorder’ (p.726). In this model, drug use is a marker for better premorbid functioning, greater social skill and therefore better outcome. Evidence to support this

1InforMH,

Mental Health and Drug and Alcohol Office, NSW Ministry of Health, North Sydney, Australia 2Discipline of Psychiatry, Sydney Medical School, University of Sydney, Sydney, Australia 3School of Population Health, University of Queensland, Brisbane, Australia Corresponding author: Grant Sara, InforMH, Macquarie Hospital, PO Box 169, North Ryde, NSW 1670, Australia. Email: [email protected] DOI: 10.1177/0004867414530008

Whether at first contact or in ongoing care, around half of Australians with a diagnosis of psychosis also have a comorbid substance use disorder. In the current issue, Large and colleagues report a systematic metaanalysis which underlines the impact of ongoing substance use on psychotic symptoms (Large et  al., 2014). They also touch on an intriguing finding: people with psychosis and substance disorders who cease drug use (‘former substance users’) may have better outcomes than people with psychosis who have never used substances. Put another way, substance use may be a positive prognostic sign in psychosis, as long as substance use is ceased.

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ANZJP Correspondence theory is limited. Prospective studies of drug use in adolescents typically find higher rates of drug use in more marginalised and distressed young people, not in those with greater social skills. Cannabis is ubiquitous in Australia and many other countries, requiring few social skills or networks to obtain. A ‘social skills’ theory would also predict that the association between drug use and cognition or outcome should be similar for different drug types and different diagnostic subtypes of psychosis, but there is evidence that these associations may differ for schizophrenia and bipolar disorder. Third, these findings may reflect varying degrees of personal vulnerability. A stress-diathesis model suggests that onset of psychosis without substance use reflects a significant diathesis in the person affected, whereas substances may precipitate psychosis in individuals with less intrinsic vulnerability. Therefore, when those young people cease drugs, they have better outcomes. Consistent with this, people with psychosis and substance use have fewer neurological soft signs and fewer negative symptoms than those without substance abuse (Loberg and Hugdahl, 2009; Yucel et  al., 2012). This theory would predict that substances with greater potential to precipitate psychotic symptoms, such as hallucinogens and stimulants, would trigger psychosis in people with lower levels of vulnerability. Hence, former users of those substances should have the most positive outcomes. A recent study found that drug-induced psychoses associated with amphetamines had a lower rate of transition to schizophrenia than those associated with cannabis (Niemi-Pynttari et  al., 2013). We

have also found that in people with brief, atypical and drug-induced psychoses, cannabis disorders predict a greater likelihood of transition to schizophrenia but stimulant disorders predict a lower likelihood (Sara et al., 2014a). Regardless of the mechanisms involved, an association between ceasing substance use and positive outcome has important clinical implications. A first episode of a drug-associated psychosis is one of the most frightening crises that a young person and his or her family can face. By the time of that first presentation, risk factors such as family history, age and duration of untreated psychosis are fixed. Giving up substance use is one of the few ways through which a young person can modify his or her risk of developing a more enduring illness. If ceasing drug use not only helps avoid bad outcomes but can lead to good ones, this is an important and hopeful message. Two challenges for our mental health services follow. First, we need better ways of engaging and more effective interventions for people with comorbid substance use and psychosis. Second, more research is needed to identify whether the positive effects of ceasing substance use in people with early psychosis also apply for people with more enduring psychosis diagnoses such as schizophrenia. Funding This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors.

Declaration of interest The author reports no conflicts of interest. The author alone is responsible for the content and writing of the paper.

See Review by Large et al., 2014, 48(5): 418–432.

References Lambert M, Conus P, Lubman DI, et al. (2005) The impact of substance use disorders on clinical outcome in 643 patients with first-episode psychosis. Acta Psychiatrica Scandinavica 112: 141–148. Large M, Mullin K, Gupta P, et al. (2014) Systematic meta-analysis of outcomes associated with psychosis and co-morbid substance use. Australian and New Zealand Journal of Psychiatry 48: 418–432. Loberg EM and Hugdahl K (2009) Cannabis use and cognition in schizophrenia. Frontiers in Human Neuroscience 3: 53. Mueser KT, Drake RE and Wallach MA (1998) Dual diagnosis: A review of etiological theories. Addictive Behaviors 23: 717–734. Mullin K, Gupta P, Compton MT, et  al. (2012) Does giving up substance use work for patients with psychosis? A systematic metaanalysis. Australian and New Zealand Journal of Psychiatry 46: 826–839. Niemi-Pynttari JA, Sund R, Putkonen H, et  al. (2013) Substance-induced psychoses converting into schizophrenia: A register-based study of 18,478 Finnish inpatient cases. Journal of Clinical Psychiatry 74: e94–99. Paparelli A, Di Forti M, Morrison PD, et al. (2011) Drug-induced psychosis: How to avoid star gazing in schizophrenia research by looking at more obvious sources of light. Frontiers in Behavioural Neuroscience 5: 1–9. Sara G, Burgess P, Malhi G, et  al. (2014a) The impact of cannabis and stimulant disorders on diagnostic stability in psychosis. Journal of Clinical Psychiatry (in press). Sara GE, Burgess PM, Malhi GS, et  al. (2014b) Cannabis and stimulant disorders and readmissions 2 years after first-episode psychosis. British Journal of Psychiatry. Epub ahead of print 27 February 2014. DOI: 10.1192/bjp. bp.113.135145. Yucel M, Bora E, Lubman DI, et  al. (2012) The impact of cannabis use on cognitive functioning in patients with schizophrenia: A metaanalysis of existing findings and new data in a first-episode sample. Schizophrenia Bulletin 38: 316–330.

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Drugs and psychosis and now for some good news.

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