Introduction
Simon Evans is a 32-year-old diagnosed with schizophrenia at the age of 20. He is reported to have an educational qualification but has been unsuccessful in maintaining his past employment. He is a known chain smoker, he inconsistently consumes his meals, and leads a poor lifestyle. He is presently on clonazepam for the management of his schizophrenia. This paper then presents an evidence-based nursing care plan for Evans that draws upon pertinent theoretical concepts supporting the use of a shared decision making with a rationale for the client entered approach and recovery model for the holistic management of Evans’ schizophrenia.
This paper aims at presenting the epidemiological pattern and prevalence of schizophrenia within the global setting, more so in the British setup. Secondly, the defining symptomatology of the disease will also be explored. Thirdly, a definition of the clinical decision making in addition to its importance in psychiatric nursing will be highlighted. In light of the case presented, an assessment of the physical and mental health needs of the patient will be presented. Finally, a patient centred care plan that prioritises the needs of the patient through the recovery process and their rationale will also be presented.
Definition and Prevalence of Schizophrenia
Schizophrenia is a Greek word, with “Shizo” meaning split and “Phren” meaning mind (Townsend 2015). Schizophrenia is described as a complicated Psychobiological illness that causes the affected person to experience significant changes in personality and disabilities in conducting their normal lives. The global prevalence of schizophrenia is estimated at 21 million people. The disease affects more males (12 million) than females (9 million). In the UK, NHS manages about 280,000 schizophrenic cases (Living with schizophrenia 2017). Men get affected in their mid-twenties whereas women get affected in their late twenties (Schultz and Videbeck 2009). Schizophrenia may lead to debilitating mental disability; schizophrenics have 2-2.5 time higher risk of dying from other complications of the disease such as cardiovascular, metabolic and infectious diseases as compared to the normal population. Schizophrenia is diagnosed through the presence of various symptoms based on patient reported or observed behavioural changes that have persisted for at least six months.
The Pathogenic Processes of Schizophrenia
Whereas the specific pathogenic processes of the illness remain unclear, research into the area presents that the aetiology of the illness is multifactorial, encompassing environmental, genetic, and neural factors (Miller and Mason 2011). The dysregulation of brain neurotransmitters glutamate, dopamine and/or GABA has been implicated in the positive and negative symptomatology of schizophrenia (Lieberman and Murray 2012; Mahone et al. 2016). Treatment with antipsychotic medications primarily works through their affinity of the dopamine receptors (D2) and their effect on other neurotransmitter receptors (Holt and Peveler 2006). Antipsychotic medications are recommended in combination with psychosocial patient therapy for both the management and minimization of schizophrenic relapses in diagnosed patients (American Psychiatric Association, APA, 2000).
Disease Symptomatology and its Complications
In schizophrenia, the affected individual experience numerous significant changes in their personalities and a concomitant impairment of the ability to carry out their lives normally (Brown, Barraclough and Inskip 2000). Schizophrenia, as any other mental illness is diagnosed through the presentation of various symptoms, either reported by the patient or elicited during a medical examination. Revealed from Simon`s history, for example, are various patient positive and negative symptoms that are preceded by a prodromal period which later progresses to deterioration in personal functioning and episodes of behavioural disturbances, hallucination and delusions.
According to Miller and Mason (2011), the DSM classification of the symptomatology associated with schizophrenia is categorised into two broad groupings, the positive and negative symptoms. The positives are defined as unique patient experiences that otherwise are recognised as abnormal in normative persons. These include visual and auditory hallucinations, delusions (having beliefs that are not based on established facts and reality), abnormal motor behaviours and extreme disorganisation (including disorganised speech that impairs normal communications) (APA 2000). The negatives are associated with the patient’s reduced or lack of ability to function normally. These include a lack of emotions, failing to change facial expressions, failing to make eye contact, speech without a monotone or inflexion, and inappropriate or total lack of body gestures during a speech (Schultz and Videbeck 2009).
Risk Factors for Schizophrenia
The risk factors associated, and more so trigger factors associated with schizophrenia are not clear yet; nevertheless, certain factors seem to increase the risk of developing or triggering schizophrenia episodes (APA, 2000). These include a positive history of schizophrenia in the first-degree relative, exposure of an unborn child to malnutrition, viruses and toxins especially in the first and second trimester and an increased activation of the immune system, such as in autoimmune or inflammatory conditions (Townsend 2015; Mahone et al. 2016). Other factors that have been implicated include older paternal age at conception and the consumption of psychotropic or psychoactive medications during teen years and young adulthood years.
Complications of Schizophrenia
Schizophrenia is a disease that can lead to complex emotional, behavioural and cognitive complications. Schultz and Videbeck (2009) note that if left untreated, schizophrenia can lead to severe health, behavioural and emotional problems in addition to legal and financial problems that negatively affect every area of life. Schizophrenia may complicate to depression, phobic problems and anxiety, suicidal thoughts, self-injury, poverty, drug abuse – including the abuse of prescription medications, family conflicts, homelessness, social isolation, inabilities to attend school or work and being victims of aggressive behaviour (Mahone et al. 2016). Whereas aggressive behaviours in people with schizophrenia are typically related to the lack of treatment and are uncommon, the history of substance abuse may precipitate violence (Oliver, Lubman and Fraser 2007; Gough and Peveler 2004).
Patient Assessment
Underlying nursing activity is patient assessment, more so in the field of psychiatric nursing and the broader mental health nursing – so because the foundation of this area perfuses all the aspects of a nursing care home (Mahone, Maphis and Snow 2016). This assessment should be carried out in a systematic order, utilising the theoretical frameworks of the systematic clinical decision-making nursing practice incorporation the patient’s biopsychosocial demands in the coming up of an informed patient plan of care (Schultz and Videbeck 2009; Legare et al. 2008).
Clinical Judgement and Decision Making in Nursing
Schultz and Videbeck (2009) note that the practice of nursing mental health assessment is a decision-making process that wholly relies upon collecting pertinent cues, using a defined ethical criterion which then will contribute to the overall evaluation of a client and their circumstances. The nursing assessment is divided into two broad steps, the gathering of relevant information that subsequently leads to the use of the information to make a deduction on the nursing and other healthcare interventions (Lieberman and Murray 2012; Bulechek et al. 2013; Tlach et al. 2014; Standing 2011).
According to Phaneuf (2008), clinical judgment is a complex nursing process that requires both professional and intellectual maturity. The process is particularly demanding as it requires the ability to pay attention to demands, to reason and come up with a summary of findings to enable deduction of logical conclusion. It is dependent on the nurse’s ability to observe, identify relevant information and point relationships existent between elements with subsequent reasoning (Standing 2011). Evans case requires a nurse to integrate pieces of information obtained, review it, establish relationships with known facts, analyse them and interpret the data at hand from both a rational and critical perspective.
Assessment Guidelines
The assessment of Simon entails the use of a broader approach that incorporates the examination of his mental state, conduction of a physical, psychosocial, spiritual, and strength and abilities assessments, development of a background issue, and conduction of a risk management (Standing 2011). The NICE (2014) presents a list of tools for the assessment of a schizophrenic patient. These include the BPRS, the BAVQ tool, and the LUNSERS tool, all of which can be used in determining and dealing with the identified risks. The tools are used in conjunction to one another with appropriate skill of assessment which include the ability to carry out motivational interviews, the ability of establishing a therapeutic relationship with the client, the ability to keep accurate records, ability to listen and observe, and the ability of information governance all set within the nursing skill clusters and structure of proficiency.
Assessment Issues Noted
The NICE (2014) outlines a holistic and systematic approach that can be used in assessing and determining the health and social need of Simon and meditation in addition to the suggested appropriate medications that may be needed in meeting these needs as anchored to a background of a strong-decision making for utmost productivity. A holistic approach towards a patient is crucial (NICE, 2014). Leininger (1985) presents three major points: First, the human beings who are molded into their being by naturally fixed qualities and the developed dimension of social psychological, physical and spiritual needs; the environment in which they live in is essential as it provides the resources that assist in life, including food, shelter and water; and third, the social needs of a patients would then notably include education, family, culture, technology, religion, law and a healthy social network.
Patient Symptomatology: Physical and Mental Issues Noted
Obesity, Diabetes Mellitus and Heart Diseases
Studies point out that the risk of obesity is schizophrenic patients is related to smoking, poor dietary habits, physical injury, a familial history of diabetes and the long-term negative effects of schizophrenic medications (Oliver, Lubman and Fraser 2007; Paul Weber et al. 2010). The presence of ketones in Evans’s urinalysis is an indicator of problems in glucose regulation, which if not managed at an early phase can lead to a fatal ketoacidosis. Glucose dysregulation in Evans might have resulted from poor dietary habits, inactivity, smoking and the side effects of clozapine.
Kohen (2004) argues that obesity may result also from sedentary lifestyles and poor eating lifestyles. Obesity predisposes a person to acute cardiovascular events. Additionally, obesity can contribute to other lifestyle diseases such as diabetes. Studies have shown that schizophrenia may contribute to obesity because of the metabolic side effects of antipsychotics.
Smoking
Mitchell et al. (2013) point out that persons with bipolar or schizophrenia have a three-time higher risk of smoking as compared to healthy individuals. Neurobiological, social and behavioural reasons have been implicated for the high prevalence of smoking in these groups. The rationale for smoking among schizophrenics varies. They smoke because it is a preformed routine or habit, as a means of relaxing, as a means of forming social relationships, for pleasure purposes or as a manner of gaining their lives’ control (Brown, Barraclough, and Inskip 2000).
Inability to Keep a Job
According to Salkever, Slade, and Karakus (2003), job losses among people with schizophrenia are high because of the inability to maintain steady working schedules, unpredictable and episodes negative symptoms, medication side effects and difficulties in coping with the stresses of work. This then contributes to higher dependence levels among schizophrenics.
Weight Gain
In a 2003 survey conducted by McMacreadie, 102 schizophrenic participants were identified. It was observed that 70% of the participants smoked, with 86% of the women and 70% of the men being overweight. 53% of the participants had elevated serum cholesterol. Evans has a BMI of 30.5, which is above the normal ranges of 18.5 -24.9 thereof classified as mildly obese (Paulweber et al. 2010).
Yusuf et al. (2004) explain that uncontrolled weight gain is a risk factor for acute cardiovascular events such as heart attacks. Clozapine has been implicated for the weight gain in schizophrenics (Mccreadie 2003; Paulweber et al. 2010). In a research conducted by Umbricht, Pollack, and Kane (1994), patients on 500-600 mg daily clozapine for up to 90 months became overweight.
Clinical Decision Making
Psychiatric nursing utilises a biopsychosocial model of holistic patient care that entails client education, encouraging self-management and offering spiritual support for persons with schizophrenia; in which the pivotal role of the client perspective on the treatment decision is reiterated (NICE 2014; Rubin, Trawver and Springer 2013). The therapeutic use of self, as presented by Peplau in Mahone, Maphis, and Snow (2016), has evolved from a simple client education to the discussion and confirmation of the preferences of a client, to acting as an advisor and ultimately encouraging the desired independence levels of the client. The selection of appropriate behavioural therapies to conduct administered medication through the use of shared decision making is one strategy that may lead to the ultimate improvement of treatment follow-through (Deegan and Drake 2006; Haman et al. 2006).
Pharmacological and Non-Pharmacological Patient Treatment and their Rationale
The effective management of a mental illness and thereof provision of the necessary physical health needs of a patient entails the drafting of a prudent package encompassing a multidisciplinary psychiatric care involving adequate pharmacological interventions (Bulechek et al. 2013; Colombo et al. 2003). Managing Evans’s diet will go a long way in the long term management of overweight. Evans can be advised to take a proactive approach to the prevention of further weight gain in conjunction to losing weight and observing a proper diet. Exercise and dietary counselling set within a behavioural modification program are necessary for a sustained control of weight (Holt and Peveler 2006). Imperatively, Evans can then be encouraged to stop smoking. Smoking cessation also reduces the metabolic side effects of clozapine (Mccreadie 2003).
A drafted psychiatric and psychological health care plan for Evans would incorporate his perceptions. The patient will also require support in certain areas, all of which have to be written in the care plan in an order of importance as influenced by risk assessment, after which the nurse can determine what goals can be realistically achieved in the short term and in the long term. This plan of care would enable the nurse in charge to select an intervention that will help minimise these problems and their relapses for the end actualization of the desired goals (Bulechek et al., 2013). Nursing Interventions and their Rationale
The Promotion of Mental Health
According to Dickens et al. (2012), recovery is a change process through which a patient would improve their wellness and general health, living a self-directed life with the ultimate target of reaching their maximal potential. This model ideally emphasises the importance of using appropriate communication tools and seeking to release the powerful synergies of personal medicine and psychosocial treatment for the management of illnesses (Kingdom and Turkington 2005). Personalised medicine here defined as client based acts of initiating self-care that ultimately lead to the prevention of relapses and improve on a client based reported outcomes (Roder and Medalia 2010; Hamann et al. 2006; Appendix A).
Psychiatric nurses employ the biopsychosocial model of holistic care in the improvement of a psychiatric patients’ health. (Appendix A) Ideally, the model involves educating the client, encouraging self-management, and offering spiritual support for the patient; in which the perspective of the client in decisions on their treatment is an important point of emphasis. Peplasu’s ‘therapeutic use of self’ has metamorphosed within the settings of psychiatric nursing from a simplistic education of the client to the discussion and confirmation of the preferences of the client, acting as the client advisor and encouraging the patient to attain their desired levels of independence (Mahone, Maphis and Snow 2016).
The rationale for selecting appropriate behavioural therapies in conjunction with medication using the shared decision making strategy is one model that may ultimately improve on the various aspects of treatment follow through (Deegan and Drake 2006). Within the fabric of shared decision making, a paired style of collaborative communication involving decision-making tools is used to introduce clinical information that is relevant to the patient’s health experiences, the held cultural values, preferences, and beliefs (Adams and Drake 2006; Makoul and Clayman 2006).
Shared Decision Making in the Case of Evans
Using a star plan model that encourages internal consistencies, with an effective underlying recovery-oriented construct such as the mental health recovery care will go a long way in helping Evans’ full recovery (Dickens et al. 2012; Patel, Bakken and Ruland 2008; Tlach et al. 2014). Evans’ mental health recovery care will entail the support and appraisal of changes of mature psychotic patients, comprising various dimensions that are central to his recovery journey. These dimensions include managing his self-care/physical health goals, improving living skills, improve social networks, relationships, work, management of addictive behaviours, carrying out responsibility, identifying self-esteem issue and developing trust and hope (NICE 2014; Mahone, Maphis and Snow 2016).
The importance of family and social support
The national service framework model, for example, outlines a policy guideline that acknowledges their important role played by patient families, including their caregivers, therefore backing the practice designing interventions (Bulechek et al. 2013). Evan’s mother, who already is actively involved in family therapy to help her son recover, will be encouraged to continue doing so, in lieu to the support of the nurse. The rationale for this is that family therapy is important and ought to be continued, as research has shown that psychoeducation and family may minimise the relapse of schizophrenic relapses in patients.
The provision of carer-focused education and support programs to the family members of persons with schizophrenia at early times promotes a message of positive recovery (Dickens et al., 2012). That the carers of persons with schizophrenia should be supported, thereof, Evan’s mother can be provided with information on the diseases, the effective use of drugs, the importance of adhering to the medication and the identification and management of schizophrenic symptomatology in addition to accessing problem solving and support services in real time (Prasad and IGI Global 2017).
Enrollment in an Art Therapy Class and Offering Him Job Training
Enrolling the patient in art therapies aimed at the promotion of one’s creative expression is important as it lowers patient hallucinations, stimulates memory and alleviates the negative symptomatology. The patient can be encouraged to join an art therapy group, which may give him a chance of relating to experiences by other members. Another recovery strategy will also include offering him a job-related training and subsequently enrol him in a supportive employment program as part of the efforts of encouraging him to work (Salkever, Sladeand and Karakus 2003).
Encouragement to Continue with the CBT
Since Evans is already on the Cognitive Behavioral Therapy (CBT), he can be encouraged to continue. CBT is one of the effective therapies for the promotion of long-term integrative approach to schizophrenia (Kingdom and Turkington 2005). On return to the community, Evans can be encouraged to participate in an Expert patient program. The rationale for joining an Expert Patient program is that it can give him confidence in taking greater responsibility for his physical well-being, change his bizarre dressing and unusual behaviour, and improve on his sleeping patterns (Deegan 2007).
Conclusion
Evidence-based practice supports the use of psychosocial and psychological treatment interventions in conjunction to as an all-inclusive intervention for the managements of symptomatology associated with schizophrenic disorders, ultimately contributing to lower side effects and an improved life. Presenting Evans with a nursing care plan that incorporates his involvement is mental health care accrues enhanced patient adherence to medication, satisfaction, and ultimate guideline-concordant care. A treatment package with a focus on meeting the needs of Evans, focusing on the recovery and minimising relapses would be implemented. This plan is to be reviewed and evaluated periodically by the coordinator of the care team in line with the recovery stages of the patient.
Bibliography
Adams, JR & Drake RE 2006, ‘Shared decision making and evidence-based practice.’ Community mental health journal, vol. 42, no. 1, pp. 87-105.
American Psychiatric Association, DSM-IV-TR: Diagnostic and statistical manual of mental disorder, text revision. Washington DC: American Psychiatric Association, 75.
Brown, S, Barraclough, B & Inskip H 2000, ‘Causes of excess mortality of schizophrenia.’ British Journal of Psychiatry, vol. 177, no. 3, pp. 212-217.
Bulechek, GM, Butcher, HK, Dochterman, JM & Wagner, CM 2013, Nursing Interventions Classification (NIC). St. Luis, M.O.: Elsevier/Mosby. Print Book: English.
Colombo, A, Bendelow, G, Fulford, B & Williams, S 2003, ‘Evaluating the influence of implicit model of mental disorder on processes of shared decision making within community-based multidisciplinary teams.’ Social Science & Medicine, vol. 56, no. 7, pp. 1557-1570.
Deegan, PE & Drake, RE 2006, ‘Shared decision making and medication management in the recovery process.’ Psychiatry services, vol. 57, no. 11, pp. 1636-1639.
Deegan, PE 2007, ‘The lived experience of using the psychiatric medication in the recovery process and a shared decision-making program to support it.’ Psychiatric rehabilitation journal, vol. 31, no. 1, pp. 62.
Dickens, G, Weleminsky, J, Onifade, Y & Sugarman, P 2012, ‘Recovery Star: Validating user recovery.’ The Psychiatrist Online, vol. 36, no. 2, pp. 45-50.
Gough, S & Peveler, R 2004, ‘Diabetes and its prevention: pragmatic solutions for people with schizophrenia.’ The British journal of psychiatry, vol. 184, no. 47, pp. s106-s111.
Hamann, J, Lanager, B, Winkler, V, Busch, R, Cohen, R, Leutcht, S & Kissling, W 2006, ‘Shared decision making for in-patients with schizophrenia.’ Acta Psychiatrica Scandinavica, vol. 114, no. 4, pp. 265-273.
Holt, RIG & Peveler, RC 2006, ‘Association between antipsychotic drugs and diabetes. Diabetes.’ Obesity and Metabolism, vol. 8, no. XX, pp. 125-135.
Kingdom, DG & Turkington, D 2005, Cognitive therapy of schizophrenia. New York: Guilford Press.
Kirk, SA 1999, ‘Good intentions are not enough: practice guidelines for social work.’ Research on social work practice, vol. 9, no. 3, pp. 302-310.
Kohen, D 2004, ‘Diabetes Mellitus and Schizophrenia: historical perceptive.’ British Journal of Psychiatry, vol. 184, no. 47, pp. s64-s66.
Legare, F, Ratte, S, Gravel, K & Graham, ID 2008, ‘Barriers and facilitators to implementing shared decision-making in clinical practice: update of the systematic review of health professionals’ perceptions.’ Patient education and counseling, Vol. 73, no. 3, pp. 526-535.
Leinenger, M 1985, ‘Transcultural nursing care: diversity and universality.’ Nursing and healthcare, vol. 6, no. XX, pp. 209-212.
Lieberman, JA & Murray RM 2012, Comprehensive care of schizophrenia: a textbook of clinical management. Oxford; New York: Oxford University Press.
Living with schizophrenia 2017, About Living with Schizophrenia. Retrieved from: https://www.livingwithschizophreniauk.org/facts-and-figures/
Mahone, IH, Maphis, CF & Snow, DE 2016, ‘Effective starteg9ies for nurses empowering clients with schizophrenia: medication use as a tool in recovery.’ Issues in Mental health nursing, vol. 37, no. 5, pp. 372-379.
Makoul, G, & Clayman, ML 2006, ‘An integrative model of shared decision making in medical encounters.’ Patient education and counseling, vol. 60, no. 3, pp. 301-312.
McCreadie, RG 2003, ‘Diet, smoking and cardiovascular risk in people with schizophrenia.’ The British journal of psychiatry, vol. 183, no. 6, pp. 534-539.
Miller, R & Mason, SE 2011, Diagnosis schizophrenia: a comprehensive resource for consumers, families and helping professionals. New York: Columbia University Press. Print Book: English.
Mitchell, AJ, Vancampfront, D, De Herdt, A., Yu, W & De Hert, M 2013, ‘Is the prevalence of metabolic syndrome and metabolic abnormalities increased in early schizophrenia? A comparative meta-analysis of the first episode, untreated and treated patients.’ Schizophrenia Bulletin, vol. 39, no. 2, pp. 295-305.
National Institute for clinical Excellence (NICE) 2014, Clinical Guidelines 178: Schizophrenia-core interventions in the treatment and management of schizophrenia in adult in primary and secondary care. Updated ed. London: NICE.
Oliver, D, Lubman, DI & Fraser, R 2007, ‘Tobacco smoking within Psychiatric inpatient settings: Biopsychosocial perspective.’ Australian & New Zealand Psych Journal, vol. 41, no. XX, pp. 572-580.
Patel, SR, Bakken, S & Ruland, C 2008, “Recent advances in shared decision making for mental health.’ Current opinion in psychiatry, vol. 21, no. 6, pp. 606.
Paulweber, B, Valensi, P, Lindstrom, J, Lalic, NM, Greaves, CJ, Mckee, M, et al., 2010, ‘A European evidence-based guideline for the prevention of type 2 diabetes.’ Hormones and Metabolic Research, vol. 42, no. 1, pp. s3-s36.
Phaneuf, M 2008, Clinical judgement: an essential tool in the nursing profession. Place of publication not provided.
Prasad, BV & IGI Global 2017, Chronic mental illness and the changing scope of intervention strategies, diagnosis, and treatment. Hershey, Pennsylvania (701 E. Chocolate Avenue Hershey, PA 17033, USA): IGI Global.
Roder, V & Medalia, A, 2010, Neurocognition and Social cognition in schizophrenia patients: Basic concepts and treatment. Basel [Switzerland]; New York: Karger
Rubin, A, Trawver, K & Springer, DW 2013, Psychosocial treatment of schizophrenia. Hoboken, N.J.: Wiley. Print Book
Salkever, DS, Slade, EP & Karakus, MC 2003, ‘Employment retention by a person with schizophrenia employed in non-assisted Jobs.’ Journal of Rehabilitation vol. 69, no. 4, pp. 19-26.
Schultz, JM & Videbeck, SL 2009, Lippincott’s manual of psychiatric nursing care plans. Philadelphia: Lippincott Williams and Wilkins. Print book.
Sin, J 2000, ‘One step at a time.’ Mental health care, vol. 41, no. 31, pp. 97-101.
Standing, M 2011, Clinical judgement and decision making for nursing students. Exeter. Learning Matters. Chapter 1 What is clinical judgement and decision-making in nursing?
Standing, M 2011, Clinical judgment and decision making for nursing students. Exeter: Learning Matters.
Tlach, L, Wusten, C, Daubman, A, Liebherz, S, Harter, M & Dirmaier, J 2014, ‘Information & decision-making need among people with mental disorders: a systematic review of the literature.’ Health Expectations, vol. 18, no. XX, pp.1856-1872.
Townsend, MC 2015, Psychiatry Mental Health Nursing: Concepts of care in evidence- based practice. Philadelphia; F.A Davis, pp 420.
Umbrich, DS, Polack, S & Kane, JM 1994, ‘Clozapine and weight gain.’ Journal of clinical Psychiatry, vol. 55, no. B, pp. 157-160.
Wu, MK, Wang, CK, Bai, YM, Huang, CY & Lee, SD 2007, ‘Outcomes of Obese clozapine-treated in patients with schizophrenia placed on six-month diet and physical activity program.’ Psychiatric Services, vol. 58, no. 4, pp. 544-545.
Yusuf, S., Hawken, S, Ounpu, S, Dan ST, Avezunni, A, Lanas, F, McQueen, M, Budai, A, Pais, P, Varigos, J & Lisheg, L 2004, ‘Effect of potentially modifiable risk factors associated with Myocardial infarction in 52 countries: case-control study.’ Lancet 2004 Sep 11-17, vol. 364, no. 9438, pp.937-952.