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This chapter provides a wide-ranging review of the clinical pharmacology of drugs for the treatment of schizophrenia and psychosis other than clozapine. These are dopamine receptor antagonists and dopamine partial agonists (as per the new Neuroscience-based Nomenclature (NbN) classification). This chapter covers their pharmacodynamics, pharmacokinetics, adverse effects, the latest evidence regarding their ‘antipsychotic’ mechanism of action, their use in the acute and maintenance treatment of schizophrenia, other therapeutic indications and some controversies that surround their use.
Dopamine receptor antagonists and dopamine partial agonists are commonly referred to as antipsychotics. As a clinical shorthand the term ‘antipsychotic’ is likely to remain in use.
Heart disease is the leading cause of death in schizophrenia. However, there has been little research directly examining cardiac function in schizophrenia.
To investigate cardiac structure and function in individuals with schizophrenia using cardiac magnetic resonance imaging (CMR) after excluding medical and metabolic comorbidity.
In total, 80 participants underwent CMR to determine biventricular volumes and function and measures of blood pressure, physical activity and glycated haemoglobin levels. Individuals with schizophrenia (‘patients’) and controls were matched for age, gender, ethnicity and body surface area.
Patients had significantly smaller indexed left ventricular (LV) end-diastolic volume (effect size d = −0.82, P = 0.001), LV end-systolic volume (d = −0.58, P = 0.02), LV stroke volume (d = −0.85, P = 0.001), right ventricular (RV) end-diastolic volume (d = −0.79, P = 0.002), RV end-systolic volume (d = −0.58, P = 0.02), and RV stroke volume (d = −0.87, P = 0.001) but unaltered ejection fractions relative to controls. LV concentricity (d = 0.73, P = 0.003) and septal thickness (d = 1.13, P < 0.001) were significantly larger in the patients. Mean concentricity in patients was above the reference range. The findings were largely unchanged after adjusting for smoking and/or exercise levels and were independent of medication dose and duration.
Individuals with schizophrenia show evidence of concentric cardiac remodelling compared with healthy controls of a similar age, gender, ethnicity, body surface area and blood pressure, and independent of smoking and activity levels. This could be contributing to the excess cardiovascular mortality observed in schizophrenia. Future studies should investigate the contribution of antipsychotic medication to these changes.
Psychotic disorders are associated with metabolic abnormalities including alterations in glucose and lipid metabolism. A major challenge in the treatment of psychosis is to identify patients with vulnerable metabolic profiles who may be at risk of developing cardiometabolic co-morbidities. It is established that both central and peripheral metabolic organs use lipids to control energy balance and regulate peripheral insulin sensitivity. The endocannabinoid system, implicated in the regulation of glucose and lipid metabolism, has been shown to be dysregulated in psychosis. It is currently unclear how these endocannabinoid abnormalities relate to metabolic changes in psychosis. Here we review recent research in the field of metabolic co-morbidities in psychotic disorders as well as the methods to study them and potential links to the endocannabinoid system. We also describe the bioinformatics platforms developed in the EU project METSY for the investigations of the biological etiology in patients at risk of psychosis and in first episode psychosis patients. The METSY project was established with the aim to identify and evaluate multi-modal peripheral and neuroimaging markers that may be able to predict the onset and prognosis of psychiatric and metabolic symptoms in patients at risk of developing psychosis and first episode psychosis patients. Given the intrinsic complexity and widespread role of lipid metabolism, a systems biology approach which combines molecular, structural and functional neuroimaging methods with detailed metabolic characterisation and multi-variate network analysis is essential in order to identify how lipid dysregulation may contribute to psychotic disorders. A decision support system, integrating clinical, neuropsychological and neuroimaging data, was also developed in order to aid clinical decision making in psychosis. Knowledge of common and specific mechanisms may aid the etiopathogenic understanding of psychotic and metabolic disorders, facilitate early disease detection, aid treatment selection and elucidate new targets for pharmacological treatments.
The first episode of psychosis is a critical period in the emergence of cardiometabolic risk.
We set out to explore the influence of individual and lifestyle factors on cardiometabolic outcomes in early psychosis.
This was a prospective cohort study of 293 UK adults presenting with first-episode psychosis investigating the influence of sociodemographics, lifestyle (physical activity, sedentary behaviour, nutrition, smoking, alcohol, substance use) and medication on cardiometabolic outcomes over the following 12 months.
Rates of obesity and glucose dysregulation rose from 17.8% and 12%, respectively, at baseline to 23.7% and 23.7% at 1 year. Little change was seen over time in the 76.8% tobacco smoking rate or the quarter who were sedentary for over 10 h daily. We found no association between lifestyle at baseline or type of antipsychotic medication prescribed with either baseline or 1-year cardiometabolic outcomes. Median haemoglobin A1c (HbA1c) rose by 3.3 mmol/mol in participants from Black and minority ethnic (BME) groups, with little change observed in their White counterparts. At 12 months, one-third of those with BME heritage exceeded the threshold for prediabetes (HbA1c >39 mmol/mol).
Unhealthy lifestyle choices are prevalent in early psychosis and cardiometabolic risk worsens over the next year, creating an important window for prevention. We found no evidence, however, that preventative strategies should be preferentially directed based on lifestyle habits. Further work is needed to determine whether clinical strategies should allow for differential patterns of emergence of cardiometabolic risk in people of different ethnicities.
Given that only a subgroup of patients with schizophrenia responds to first-line antipsychotic drugs, a key clinical question is what underlies treatment response. Observations that prefrontal activity correlates with striatal dopaminergic function, have led to the hypothesis that disrupted frontostriatal functional connectivity (FC) could be associated with altered dopaminergic function. Thus, the aim of this study was to investigate the relationship between frontostriatal FC and striatal dopamine synthesis capacity in patients with schizophrenia who had responded to first-line antipsychotic drug compared with those who had failed but responded to clozapine.
Twenty-four symptomatically stable patients with schizophrenia were recruited from Seoul National University Hospital, 12 of which responded to first-line antipsychotic drugs (first-line AP group) and 12 under clozapine (clozapine group), along with 12 matched healthy controls. All participants underwent resting-state functional magnetic resonance imaging and [18F]DOPA PET scans.
No significant difference was found in the total PANSS score between the patient groups. Voxel-based analysis showed a significant correlation between frontal FC to the associative striatum and the influx rate constant of [18F]DOPA in the corresponding region in the first-line AP group. Region-of-interest analysis confirmed the result (control group: R2 = 0.019, p = 0.665; first-line AP group: R2 = 0.675, p < 0.001; clozapine group: R2 = 0.324, p = 0.054) and the correlation coefficients were significantly different between the groups.
The relationship between striatal dopamine synthesis capacity and frontostriatal FC is different between responders to first-line treatment and clozapine treatment in schizophrenia, indicating that a different pathophysiology could underlie schizophrenia in patients who respond to first-line treatments relative to those who do not.
Converging lines of evidence implicate an important role for the immune system in schizophrenia. Microglia are the resident immune cells of the central nervous system and have many functions including neuroinflammation, axonal guidance and neurotrophic support. We aimed to provide a quantitative review of in vivo PET imaging studies of microglia activation in patients with schizophrenia compared with healthy controls.
Demographic, clinical and imaging measures were extracted from each study and meta-analysis was conducted using a random-effects model (Hedge's g). The difference in 18-kDa translocator protein (TSPO) binding between patients with schizophrenia and healthy controls, as quantified by either binding potential (BP) or volume of distribution (VT), was used as the main outcome. Sub-analysis and sensitivity analysis were carried out to investigate the effects of genotype, ligand and illness stage.
In total, 12 studies comprising 190 patients with schizophrenia and 200 healthy controls met inclusion criteria. There was a significant elevation in tracer binding in schizophrenia patients relative to controls when BP was used as an outcome measure, (Hedge's g = 0.31; p = 0.03) but no significant differences when VT was used (Hedge's g = −0.22; p = 0.29).
In conclusion, there is evidence for moderate elevations in TSPO tracer binding in grey matter relative to other brain tissue in schizophrenia when using BP as an outcome measure, but no difference when VT is the outcome measure. We discuss the relevance of these findings as well as the methodological issues that may underlie the contrasting difference between these outcomes.
Ethnic minority individuals have an increased risk of developing a psychotic disorder, particularly if they live in areas of ethnic segregation, or low own group ethnic density. The neurobiological mechanisms underlying this ethnic minority associated risk are unknown. We used functional MRI to investigate neural responses to faces of different ethnicity, in individuals of black ethnicity, and a control group of white British ethnicity individuals.
In total 20 individuals of black ethnicity, and 22 individuals of white British ethnicity underwent a 3T MRI scan while viewing faces of black and white ethnicity. Own group ethnic density was calculated from the 2011 census. Neighbourhood segregation was quantified using the Index of Dissimilarity method.
At the within-group level, both groups showed greater right amygdala activation to outgroup faces. Between groups, the black ethnicity group showed greater right amygdala activation to white faces, compared to the white ethnicity group. Within the black ethnicity group, individuals living in areas of lower own group ethnic density showed greater right amygdala reactivity to white faces (r = −0.61, p = 0.01).
This is the first time an increased amygdala response to white faces has been demonstrated in individuals of black ethnicity. In the black ethnicity group, correlations were observed between amygdala response and neighbourhood variables associated with increased psychosis risk. These results may have relevance for our understanding of the increased rates of paranoia and psychotic disorders in ethnic minority individuals.
The extent of metabolic and lipid changes in first-episode psychosis (FEP) is unclear.
To investigate whether individuals with FEP and no or minimal antipsychotic exposure show lipid and adipocytokine abnormalities compared with healthy controls.
We conducted a meta-analysis of studies examining lipid and adipocytokine parameters in individuals with FEP and no or minimal antipsychotic exposure v. a healthy control group. Studies reported fasting total cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides and leptin levels.
Of 2070 citations retrieved, 20 case–control studies met inclusion criteria including 1167 patients and 1184 controls. Total cholesterol and LDL cholesterol levels were significantly decreased in patients v. controls, corresponding to an absolute reduction of 0.26mmol/L and 0.15mmol/L respectively. Triglyceride levels were significantly increased in the patient group, corresponding to an absolute increase of 0.08 mmol/L However, HDL cholesterol and leptin levels were not altered in patients v. controls.
Total and LDL cholesterol levels are reduced in FEP, indicating that hypercholesterolaemia in patients with chronic disorder is secondary and potentially modifiable. In contrast, triglycerides are elevated in FEP. Hypertriglyceridaemia is a feature of type 2 diabetes mellitus, therefore this finding adds to the evidence for glucose dysregulation in this cohort. These findings support early intervention targeting nutrition, physical activity and appropriate antipsychotic prescription.
Patients who recover from an acute episode of psychosis are frequently prescribed prophylactic antipsychotics for many years, especially if they are diagnosed as having schizophrenia. However, there is a dearth of evidence concerning the long-term effectiveness of this practice, and growing concern over the cumulative effects of antipsychotics on physical health and brain structure. Although controversy remains concerning some of the data, the wise psychiatrist should regularly review the benefit to each patient of continuing prophylactic antipsychotics against the risk of side-effects and loss of effectiveness through the development of supersensitivity of the dopamine D2 receptor. Psychiatrists should work with their patients to slowly reduce the antipsychotic to the lowest dose that prevents the return of distressing symptoms. Up to 40% of those whose psychosis remits after a first episode should be able to achieve a good outcome in the long term either with no antipsychotic medication or with a very low dose.
It is unknown whether prodromal services improve outcomes in those who go on to develop psychosis, and whether these patients are demographically different from the overall first-episode population.
To compare sociodemographic features, duration of untreated psychosis, hospital admission and frequency of compulsory treatment in the first year after the onset of psychosis in patients who present to prodromal services with patients who did not present to services until the first episode of psychosis.
We compared two groups of patients with first-episode psychosis: one who made transition after presenting in the prodromal phase and the other who had presented with a first episode.
The patients who had presented before the first episode were more likely to be employed and less likely to belong to an ethnic minority group. They had a shorter duration of untreated psychosis, and were less likely to have been admitted to hospital and to have required compulsory treatment.
Patients who develop psychosis after being engaged in the prodromal phase have a better short-term clinical outcome than patients who do not present until the first episode. Patients who present during first episodes may be more likely to have sociodemographic features associated with relatively poor outcomes.
N-methyl-d-aspartate receptor (NMDA-R) autoantibodies have
been reported in people with acute psychosis. We hypothesised that their
presence may be implicated in the aetiology of treatment-refractory
psychosis. We sought to ascertain the point prevalence of NMDA-R antibody
positivity in patients referred to services for treatment-refractory
psychosis. We found that 3 (7.0%) of 43 individuals had low positive NMDA-R
antibody titres. This suggests that NMDA-R autoantibodies are unlikely to
account for a large proportion of treatment-refractory psychosis.
Schizophrenia is usually classified based on clinical presentation. However, the conventional paranoid–disorganised–residual distinctions have had limited clinical utility. Here we draw on the evidence for differences in pathophysiology underlying treatment response to propose a subclassification based on neurobiology to guide diagnostic testing and treatment.
The hypothesis that cortical dopaminergic alterations underlie aspects of schizophrenia has been highly influential.
To bring together and evaluate the imaging evidence for dopaminergic alterations in cortical and other extrastriatal regions in schizophrenia.
Electronic databases were searched for in vivo molecular studies of extrastriatal dopaminergic function in schizophrenia. Twenty-three studies (278 patients and 265 controls) were identified. Clinicodemographic and imaging variables were extracted and effect sizes determined for the dopaminergic measures. There were sufficient data to permit meta-analyses for the temporal cortex, thalamus and substantia nigra but not for other regions.
The meta-analysis of dopamine D2/D3 receptor availability found summary effect sizes of d =–0.32 (95% CI −0.68 to 0.03) for the thalamus, d =–0.23 (95% CI −0.54 to 0.07) for the temporal cortex and d = 0.04 (95% CI −0.92 to 0.99) for the substantia nigra. Confidence intervals were wide and all included no difference between groups. Evidence for other measures/regions is limited because of the small number of studies and in some instances inconsistent findings, although significant differences were reported for D2/D3 receptors in the cingulate and uncus, for D1 receptors in the prefrontal cortex and for dopamine transporter availability in the thalamus.
There is a relative paucity of direct evidence for cortical dopaminergic alterations in schizophrenia, and findings are inconclusive. This is surprising given the wide influence of the hypothesis. Large, well-controlled studies in drug-naive patients are warranted to definitively test this hypothesis.
Clozapine is the only antipsychotic drug licensed for treatment-resistant schizophrenia but its use is often delayed. Since previous studies, national guidelines on the use of clozapine and other antipsychotics have been disseminated to clinicians.
To determine the theoretical delay to clozapine initiation and to quantify the prior use of antipsychotic polypharmacy and high-dose antipsychotic treatment.
Clinico-demographic data were extracted from the treatment records of all patients commencing clozapine in our centre between 2006 and 2010.
Complete records were available for 149 patients. The mean theoretical delay in initiating clozapine was 47.7 months (s.d. = 49.7). Before commencing clozapine, antipsychotic polypharmacy and high-dose treatment was evident in 36.2 and 34.2% of patients respectively. Theoretical delay was related to illness duration (β = 0.7, P<0.001) but did not differ by gender or ethnicity.
Substantial delays to clozapine initiation remain and antipsychotic polypharmacy and high doses are commonly used prior to clozapine, despite treatment guidelines.
Sexual dysfunction is common in psychotic disorder but it is not clear
whether it is intrinsic to the development of the illness or secondary to
To compare sexual function in people at ultra-high risk (UHR) of a
psychotic disorder, patients with first-episode psychosis predominantly
taking antipsychotic drugs and healthy volunteers.
Sexual function was assessed in a UHR group (n = 31), a
group with first-episode psychosis (n = 37) and a
matched control group of healthy volunteers (n = 56)
using the Sexual Function Questionnaire.
There was a significant effect of group on sexual function
(P<0.001). Sexual dysfunction was evident in 50%
of the UHR group, 65% of first-episode patients and 21% of controls.
Within the UHR group, sexual dysfunction was more marked in those who
subsequently developed psychosis than in those who did not. Across all
groups the severity of sexual dysfunction was correlated with the
severity of psychotic symptoms (P<0.001). Within the
first-episode group there was no significant difference in sexual
dysfunction between patients taking prolactin-raising v.
Sexual dysfunction is present prior to onset of psychosis, suggesting it
is intrinsic to the development of illness unlikely to be related to the
prolactin-raising properties of antipsychotic medication.
This study assessed the prescription of potentially nephrotoxic non-steroidal anti-inflammatory drugs (NSAIDs) to patients with chronic kidney disease (CKD) in general practice.
CKD poses a considerable disease burden in the UK. Guidelines state that caution should be exercised when prescribing NSAIDs to CKD patients, due to increased risk of rapid kidney disease progression.
We reviewed the medical records of 1427 patients with CKD Stages 3–5 in seven general practices in West Yorkshire.
A total of 792 (55.5%) were prescribed NSAIDs; 128 (9%) of these were prescribed NSAIDs excluding low-dose aspirin. Twenty-three (20.2%) patients who were prescribed NSAIDs had no record of CKD monitoring in the preceding year.
Prescription of NSAIDs is likely to be contributing to unnecessary renal impairment.