Increasingly, a large number of neuroimaging techniques are being developed and used for research, with some ultimately entering clinical practice (Scheltens et al., 2002; O'Brien, 2007). For most clinicians working with dementia patients, it can be very hard to keep abreast of developments in the field. For example, when does a potentially exciting new technique for diagnosis or monitoring disease progression become sufficiently validated to be accepted by the scientific community? When does such a validated method for research then become justified for use in routine clinical practice? Closely linked to this, when does one have sufficient evidence that a diagnostic tool changes practice to engage with discussions with those commissioning or paying for health services to make a strong business case for funding for the method to be made available? It is also often far from clear, when faced with a patient with cognitive difficulties, exactly what scan should be requested, at what point and why. If one scan is uninformative or equivocal then what should be the next steps? Are there factors that limit sensitivity of a given technique, such as age? Is it worth suggesting another form of brain imaging to find further information, should one wait and monitor the patient clinically over time, or even repeat the same scan to look at progression? These are challenging but important questions which are all addressed in this supplement. Different papers look critically at what imaging methods are currently available – or may very soon become available – in the clinic, what they can show in particular circumstances, how they should be interpreted and how and when such scans should be requested.

Early onset Alzheimer's disease (EOAD) poses considerable challenges to physicians both in diagnostics and treatment, to patients and caregivers trying to cope with a debilitating illness at a young age and a healthcare system that is not geared to cater to degenerating illnesses striking young persons (Van Vliet et al., 2012). Routine procedures and screening measures for elderly people possibly stricken by dementia do not assess younger dementia patients in a favourable fashion. Physicians at an outpatient clinic diagnosing elderly patients, with well established standardized cognitive batteries for an older age norm, i.e. above 65 years may have unadjusted assumptions to account for in younger patients with symptoms of EOAD (Smits et al., 2012). Although a common battery of tests is internationally widely applied in the evaluation of cognitive impairment, these tests have not been validated extensively in a sample population of AD under the age of 65.

Alcohol-related dementia (ARD) is a controversial concept. Alcohol-related brain damage (ARBD) is a term used to cover a spectrum of conditions and disorders: this includes alcohol-related dementia, Korsakoff's syndrome, Wernicke's encephalopathy, alcohol-related brain injury, and alcohol amnesic syndrome. In other words, these are the conditions that have been induced by chronic alcohol consumption, resulting in some degree of brain damage. The prevalence data are varied.

Aggressive and violent behavior is a problem throughout healthcare services (Behar et al., 2008). The incidence of such acts is known to be over two and half times greater in mental health settings than in general hospital environments (National Audit Office, 2003). All types of aggression may have negative physical and psychological consequences for the victim, and therefore none ought not to be overlooked. However, one particularly serious feature is physical assault, which may result in a physical injury to the victim, although reported levels are relatively low (Stubbs et al., 2009). Physical assault may also affect the psychological, emotional and spiritual well-being of health staff and a minority may go on to develop post-traumatic stress type symptoms (Needham et al., 2005). Indeed, these symptoms may last longer than the original physical injury itself (Needham et al., 2005).

Aggression and violence are frequent events in healthcare settings across the globe, with mental health and old age settings often frequenting top spot in incidence lists (Hodgson et al., 2004, Behar et al., 2008). Some may underestimate the challenging nature of older age psychiatric patients, but the reality is that this population can display high levels of aggressive and violent behavior (Stewart et al., 2008). The potentially challenging nature of this population was revealed in a recent study in the U.K., which reported 2753 episodes of aggressive behavior over a three month period (Stewart et al., 2008). Over half of these aggressive displays were in the form of physical aggression, and displays of this type of behavior increase the likelihood of healthcare staff having to employ physical intervention (Stewart et al., 2008). Physical intervention is a form of hands-on physical restraint that involves trained staff employing physical holding techniques to move and restrict the movement of the aggressive patient.

We report a Malay man, with underlying chronic medical illnesses, presenting with positive symptoms of schizophrenia, including Capgras syndrome (CS) at the age of 73. Physical examination and blood investigations were normal and brain CT scan showed age-related cerebral atrophy. Neuropsychological assessment showed probable right hemisphere lesions but relatively intact memory and intellectual functions. Several neuroleptics including depot injections were tried but ineffective. Positive symptoms including CS eventually improved with clozapine before his death from myocardial infarction. This case report highlights the uncommon occurrence of CS in treatment resistant schizophrenia (TRS) of very late onset and its treatment challenges.

Compared with the rather uniform cognitive syndrome in Alzheimer's disease (AD), behavioral and psychological symptoms of dementia (BPSD) are considerably more heterogeneous in terms of incidence, prevalence, and association with disease duration and severity of dementia (Hope et al., 1999). The neurobiologic basis of AD is obviously less of a determinant of noncognitive symptoms than of cognitive symptoms. Therefore, the possible psychological and social causes of BPSD, such as premorbid personality, should be considered. Underlying personality traits not only shape a person's response to normal aging, but also set the stage for a range of responses to age-related stress and brain disease (Agronin, 1998).

Alzheimer's disease (AD) is now recognized as a major cause of morbidity and mortality in elderly populations throughout the world. Tragically, no clearly effective treatment for this major illness entity has emerged. In part, the lack of an effective treatment is the result of an absence of fundamental knowledge regarding the etiology and pathogenesis of the illness. However, treatment implies the amelioration of symptoms, not cure. In other neuropsychiatric illnesses such as schizophrenia, major depression, and idiopathic Parkinson's disease, there is a similar absence of knowledge regarding etiology and, to a greater or lesser extent, regarding pathogenesis. Nevertheless, symptomatic treatment for these other neuropsychiatric illnesses is available. The same potential for symptomatic treatment exists in AD. The absence of consensus or systematic information regarding treatment in AD is in large part due to the failure to apply appropriate methodologies to symptomatic assessment and pharmacologic treatment.