I explore implementation of the National Institute for Clinical Excellence's clinical guidelines for schizophrenia at an individual practitioner level and at an organisational level. Integrating effective individual and team approaches into a systematic organisational approach with collaborative working between managers, clinicians and service users will be essential to successful implementation and is likely to require a strong lead from senior clinicians. Implementation is likely to be best achieved through a sense of ownership of the guidelines and a process that borrows from their spirit, which emphasises collaboration, building on the strengths and good practice already present. Although full implementation will require additional resources, current resources must be employed effectively. The task of implementation is immense, however, and in some areas resource deficiencies and other structural problems might present insurmountable obstacles.

The prevalence of coexisting substance misuse and psychiatric disorder (dual diagnosis, comorbidity) has increased over the past decade, and the indications are that it will continue to rise. There have simultaneously been unprecedented developments in the pharmacological treatment of alcohol, opiate and nicotine misuse. Here we evaluate the evidence on the use of some of these treatments in dual diagnosis (with psychotic, mood and anxiety disorders). The evidence base is limited by the exclusion of mental illness when pharmacological agents for substance misuse are evaluated and vice versa. We set the available information within the context of the psychosocial management of comorbid substance misuse and mental illness, and the framework for service delivery recommended by UK national policy.

Mental health services are not yet organised to allow patients with personality disorders easy access, and practitioners lack the necessary skills to implement effective treatment. A number of service models have developed, albeit without a clear evidence-base. These include sole-practitioner, divided-functions and specialist-team models. In general, a divided-functions or specialist-team model is probably best for reducing risk and improving outcomes. Both models present difficulties with integrating treatment, but these can be overcome by good communication. Good management of patients requires careful assessment of need and risk, a consistent approach, constancy of staff, team coherence and adequate in-patient support. Not all practitioners can treat patients with personality disorders and the interpersonal skills of the mental health professional may be crucial in maintaining a patient in treatment.

The risk of suicide is higher during the period immediately following discharge from in-patient psychiatric care than at any other time in a service user's life. Demographic and clinical risk factors for suicide in this period are similar to those for suicide at other times and may not be specific enough to enable identification of those at greatest risk. Epidemiological studies suggest that factors related to service organisation and delivery (e.g. social support and continuity of care) are also important in the aetiology of suicide following hospital discharge. Interventions aimed at helping people in the period immediately following discharge from in-patient care have been developed. Although the effect of these interventions on suicidal behaviour has not been examined, available evidence suggests that efforts to increase patients' confidence and level of social support may be of value.

The motor vehicle on the road has a history of only just over 100 years. It is a major form of personal and public transport, but is also associated with hazards and risks. Many more people are killed on the roads each year in Britain than are the victims of homicide. General and forensic pyschiatric evaluation of offenders charged with or convicted of motoring offences is, however, infrequent, despite the presence of mental health problems in some of them. I describe psychiatric, criminological and legal factors associated with driving of motor vehicles, as many psychiatric patients have driving licences and have access to a vehicle or, indeed, may decide to drive unlicensed.

The emphasis on the evidence base of treatments may diminish awareness that critical appraisal of research into other aspects of psychiatric practice is equally important. There is a risk that diagnostic tests may be inappropriate in some clinical settings or the results of a particular test may be over-interpreted, leading to incorrect diagnosis. This article outlines the method of critically evaluating the validity of articles about diagnostic and screening tests in psychiatry and discusses concepts of sensitivity, specificity and predictive values. The use of likelihood ratios in improving clinical certainty that a disease is present or absent is examined.

Individual genetic variation accounts for some of the variability in response to drugs used routinely in clinical psychiatry. Psychopharmacogenetics focuses on how polymorphisms in genes affecting the mechanism of action of a drug's effect and/or metabolism (both peripheral and central) can influence an individual's clinical response to the drug, in terms of both therapeutic efficacy and adverse effects. Pharmacogenetics promises to be of substantial help in the field of psychiatric pharmacotherapy, but before research findings can be applied to clinical practice, ethical and methodological problems have to be addressed and overcome. This review summarises the most robust findings in the field and outlines how psychopharmacogenetic studies could lead to treatment individualisation.

This article is an overview of developments in psychopathy and their application to children and adolescents. A key question is whether or not psychopathy is stable throughout the lifespan. Some characteristics indicate phenotypic similarities with adult psychopathy, and current instruments appear to be measuring similar constructs across the age ranges. Although the literature on developmental aspects of psychopathy in young people is limited, a number of instruments have been designed to measure the construct. These tools appear to have reasonable construct, concurrent and predictive validity, but we cannot yet recommend their routine use in clinical practice or in the criminal justice system, given the limited evidence base on their predictive validity. At best, they should be viewed as a means of subtyping potentially high-risk groups with a view to treatment planning.

We discuss the complicated nature of communication between people from different cultural groups, perhaps using a second language. We focus on the fact that mental health practitioners and service users often have in common neither their cultural backgrounds nor their explanatory models of illness. Communication even in a shared language can be less than optimal as words carry multiple meanings. Consequently, consultations that involve culturally grounded explanatory models of illness challenge the professional. We give examples showing that reconciling different explanatory models during the consultation is a core task for psychiatrists and mental health practitioners working in multicultural settings.