The olfactory reference syndrome (ORS) is an under-recognised type of delusional disorder that has been described for more than a century. This chapter discusses ORS's history, clinical features, prevalence, treatment response, possible pathogenesis, nosological status and relationship to other psychiatric disorders, including mood disorders, schizophrenia, social phobia, and obsessive compulsive disorder (OCD). ORS can be associated with significant academic, occupational and most frequently social impairment. Impairment has been noted to result from the large amount of time spent thinking about the odour and engaging in behaviours aimed at diminishing the smell. The distress caused by ORS has been reported to lead to psychiatric hospitalisation, depression, suicidal ideation, suicide attempts and completed suicide. Most reports on medications for ORS focus on antipsychotics or antidepressants. A range of psychological approaches have been adopted in treating ORS, including individual psychotherapy, analytic psychotherapy, relaxation, paradoxical intention and behavioural therapy, such as exposure.

It is much easier to make an exact calculation of the direct treatment costs of intervention than the often hidden indirect costs of nonintervention. This chapter reviews cost-effectiveness studies that explicitly compare benefits in relation to costs and risks in other areas of medicine. It examines a number of research initiatives currently underway to study the indirect costs of psychiatric disorders and the extent to which these costs can be reversed with intervention. The chapter recommends that mechanisms to assure the quality of interventions have to be developed as part of cost-effectiveness studies if we hope to persuade policy makers to increase the allocation of health care resources to psychiatric disorders. It argues that while process assessments have to play a prominent role in any plan for the quality assurance of psychiatric interventions, special features of psychiatric disorders make them especially appropriate for outcomes assessment.