Under normal circumstances, emotional and affective signals within the brain are tempered by signals from higher brain centres, including the forebrain. These control systems ensure that responses to emotional and affective stimuli are appropriate for the environment within which they are generated. In patients with schizophrenia, these control systems are dysfunctional causing the patients to become oversensitive to such emotional stimuli and leading to the exaggerated reactions that are symptomatic of the disease [7,19].

Functional neuroimaging using techniques such as positron emission tomography (PET) and single photon emission computerised tomography (SPECT) provide a direct in vivo assessment of the expression and function of neuroreceptors, transporters and enzymes. This article examines the technical aspects of molecular imaging and the application of those techniques in drug development.

The move towards the use of second-generation antipsychotics for the treatment of schizophrenia has provoked much discussion over how to differentiate between the various second-generation agents available on the market. The aim of this review is to provide information that may help clinicians in the decision-making process. The results of comparative studies on general efficacy measures (such as the Positive and Negative Syndrome Scale [PANSS] and the Brief Psychiatric Rating Scale [BPRS]) and comparative studies on cognition do not clearly favour one second-generation agent over another. However, some differences between second-generation agents have become apparent from studies which have examined specific symptoms such as hostility, suicidal ideation and depression/anxiety. There are also differences between second-generation agents with regard to specific aspects of tolerability. For example, in a number of studies olanzapine is associated with fewer extrapyramidal symptoms (EPS) than risperidone, but treatment with risperidone or amisulpride is associated with less weight gain and somnolence. Some studies have investigated the results of switching patients from one antipsychotic agent to another. They have generally reported a successful switch to a second-generation agent.

Overall, there is not enough scientific evidence available to clearly favour one second-generation antipsychotic agent over another in terms of general efficacy or tolerability. Therefore, clinicians must make an individualised treatment decision, and select the most appropriate antipsychotic agent for each patient.

As the life expectancy of the general population increases, the population of elderly people with schizophrenia is also expected to increase. Consideration of the particular needs of these patients and the challenges associated with their management is therefore important [45].

The objective in managing patients with schizophrenia is to provide effective control of symptoms and enable the patient to reintegrate into society. Pharmacotherapy should, therefore, aim to provide optimum symptom control with minimal side effects using a simple dosage regimen. Ideally, this would be achieved through the use of a single agent. Some patients are successfully managed with a single antipsychotic drug, but it is often necessary or thought to be necessary to use a combination of agents to provide effective treatment. One European survey reported that most patients receive two to three psychotropic agents on average, but at least 5-22% receive five or more agents [53]. Unfortunately, the addition of more agents increases the risk of drug interactions, adverse events and non-compliance. This is amplified by the paucity of evidence-based medicine currently available to guide physicians in the use of combinations of agents, and the tendency of polypharmaceutical practice to be mostly driven by personal preference, clinical experience and marketing. This article therefore briefly looks at the feasibility of using various drug classes as adjunctive therapy in patients with schizophrenia.

Pharmacoeconomic studies are often performed in order to evaluate the cost-effectiveness of different treatments in clinical practice. Such studies are exerting an increasingly important influence on treatment choices in all areas of medicine, including psychiatry, and reflect the desire to contain rising costs of medical care [27]. Pharmacoeconomic analyses indicating cost savings can even be a prerequisite for inclusion of a new drug on national formularies [28].