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Journal of Psychopharmacology (Oxford,... Nov 2023Major depressive disorder (MDD) is a leading cause of global disability. Several lines of evidence implicate the dopamine system in its pathophysiology. However, the... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Major depressive disorder (MDD) is a leading cause of global disability. Several lines of evidence implicate the dopamine system in its pathophysiology. However, the magnitude and consistency of the findings are unknown. We address this by systematically reviewing in vivo imaging evidence for dopamine measures in MDD and meta-analysing these where there are sufficient studies.
METHODS
Studies investigating the dopaminergic system using positron emission tomography or single photon emission computed tomography in MDD and a control group were included. Demographic, clinical and imaging measures were extracted from each study, and meta-analyses and sensitivity analyses were conducted.
RESULTS
We identified 43 studies including 662 patients and 801 controls. Meta-analysis of 38 studies showed no difference in mean or mean variability of striatal D receptor availability ( = 0.06, = 0.620), or combined dopamine synthesis and release capacity ( = 0.19, = 0.309). Dopamine transporter (DAT) availability was lower in the MDD group in studies using DAT selective tracers ( = -0.56, = 0.006), but not when tracers with an affinity for serotonin transporters were included ( = -0.21, = 0.420). Subgroup analysis showed greater dopamine release ( = 0.49, = 0.030), but no difference in dopamine synthesis capacity ( = -0.21, = 0.434) in the MDD group. Striatal D receptor availability was lower in patients with MDD in two studies.
CONCLUSIONS
The meta-analysis indicates striatal DAT availability is lower, but D receptor availability is not altered in people with MDD compared to healthy controls. There may be greater dopamine release and lower striatal D receptors in MDD, although further studies are warranted. We discuss factors associated with these findings, discrepancies with preclinical literature and implications for future research.
Topics: Humans; Dopamine; Depressive Disorder, Major; Tomography, Emission-Computed, Single-Photon; Positron-Emission Tomography; Receptors, Dopamine D2; Dopamine Plasma Membrane Transport Proteins
PubMed: 37811803
DOI: 10.1177/02698811231200881 -
The Cochrane Database of Systematic... May 2014Pericyazine is a 3-cyano-10 (3-4'-hydroxypiperidinopropyl) phenothiazine. It is overall pharmacologically similar with chlorpromazine, though particularly sedating.... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Pericyazine is a 3-cyano-10 (3-4'-hydroxypiperidinopropyl) phenothiazine. It is overall pharmacologically similar with chlorpromazine, though particularly sedating. Dopamine receptor subtype analysis has not been performed for pericyazine, but the drug appears to induce greater noradrenergic than dopaminergic blockade. Compared to chlorpromazine, pericyazine reportedly has more potent antiemetic, antiserotonin, and anticholinergic activity.
OBJECTIVES
To evaluate the clinical effects and safety of pericyazine in comparison with placebo, typical and atypical antipsychotic agents and standard care for people with schizophrenia.
SEARCH METHODS
We searched the Cochrane Schizophrenia Group Trials Register (February 2013) which is based on regular searches of CINAHL, EMBASE, MEDLINE and PsycINFO. We inspected references of all identified studies for further trials.
SELECTION CRITERIA
All relevant randomised controlled trials focusing on pericyazine for schizophrenia and other types of schizophrenia-like psychoses (schizophreniform and schizoaffective disorders). We excluded quasi-randomised trials.
DATA COLLECTION AND ANALYSIS
Data were extracted independently from included papers by at least two review authors. Risk ratios (RR) and 95% confidence intervals (CI) of homogeneous dichotomous data were calculated. We assessed risk of bias for included studies and used GRADE to judge quality of evidence.
MAIN RESULTS
We could only include five studies conducted between 1965 and 1980. Most of the included studies did not report details of randomisation, allocation concealment, details of blinding and we could not assess the impact of attrition due to poor reporting.For the primary outcome of Global state - not improved, the confidence interval was compatible with a small benefit and increased risk of not improving with pericyazine compared with typical antipsychotics (2 RCTs, n = 122, RR 1.24 CI 0.93 to 1.66, very low quality of evidence) or atypical antipsychotics (1 RCT, n = 93, RR 0.97 CI 0.67 to 1.42, very low quality of evidence).When compared with typical antipsychotics relapse was only experienced by one person taking pericyazine (1 RCT, n = 80, RR 2.59 CI 0.11 to 61.75, very low quality of evidence).Pericyazine was associated with more extrapyramidal side effects than typical antipsychotics (3 RCTs, n = 163, RR 0.52 CI 0.34 to 0.80, very low quality of evidence) and atypical antipsychotics (1 RCT, n = 93, RR 2.69 CI 1.35 to 5.36, very low quality of evidence).The estimated risk of leaving the study early for specific reasons was imprecise for the comparisons of pericyazine with typical antipsychotics (2 RCTs, n = 71, RR 0.46 CI 0.11 to 1.90, very low quality of evidence), and with atypical antipsychotics (1 RCT, n = 93, RR 0.13 CI 0.01 to 2.42, very low quality of evidence).
AUTHORS' CONCLUSIONS
On the basis of very low quality evidence we are unable to determine the effects of pericyazine in comparison with typical or atypical antipsychotics for the treatment of schizophrenia. However, there is some evidence that pericyazine may be associated with a higher incidence of extrapyramidal side effects than other antipsychotics, and again this was judged to be very low quality evidence. Large, robust studies are still needed before any firm conclusions can be drawn.
Topics: Akathisia, Drug-Induced; Antipsychotic Agents; Humans; Phenothiazines; Randomized Controlled Trials as Topic; Schizophrenia; Spasm; Tremor
PubMed: 24825770
DOI: 10.1002/14651858.CD007479.pub2 -
Biomedicines Mar 2023Treatment resistant schizophrenia (TRS) is characterized by a lack of, or suboptimal response to, antipsychotic agents. The biological underpinnings of this clinical... (Review)
Review
Treatment resistant schizophrenia (TRS) is characterized by a lack of, or suboptimal response to, antipsychotic agents. The biological underpinnings of this clinical condition are still scarcely understood. Since all antipsychotics block dopamine D2 receptors (D2R), dopamine-related mechanisms should be considered the main candidates in the neurobiology of antipsychotic non-response, although other neurotransmitter systems play a role. The aims of this review are: (i) to recapitulate and critically appraise the relevant literature on dopamine-related mechanisms of TRS; (ii) to discuss the methodological limitations of the studies so far conducted and delineate a theoretical framework on dopamine mechanisms of TRS; and (iii) to highlight future perspectives of research and unmet needs. Dopamine-related neurobiological mechanisms of TRS may be multiple and putatively subdivided into three biological points: (1) D2R-related, including increased D2R levels; increased density of D2Rs in the high-affinity state; aberrant D2R dimer or heteromer formation; imbalance between D2R short and long variants; extrastriatal D2Rs; (2) presynaptic dopamine, including low or normal dopamine synthesis and/or release compared to responder patients; and (3) exaggerated postsynaptic D2R-mediated neurotransmission. Future points to be addressed are: (i) a more neurobiologically-oriented phenotypic categorization of TRS; (ii) implementation of neurobiological studies by directly comparing treatment resistant vs. treatment responder patients; (iii) development of a reliable animal model of non-response to antipsychotics.
PubMed: 36979877
DOI: 10.3390/biomedicines11030895 -
Basic & Clinical Pharmacology &... Jan 2019The effect of risperidone treatment in patients with schizophrenia varies according to the dopamine receptor genes. This study aimed to evaluate the relationship between... (Meta-Analysis)
Meta-Analysis
BACKGROUND
The effect of risperidone treatment in patients with schizophrenia varies according to the dopamine receptor genes. This study aimed to evaluate the relationship between genes of the dopamine receptors (D1, D2, and D3) and the effect of risperidone treatment.
METHODS
Three electronic databases (PubMed, Embase, and Cochrane Library) were searched for relevant cohort or case-control studies published before 9 May 2018. A systematic review and meta-analysis was performed for qualitative and quantitative assessment of the relationship between the dopamine receptors D1, D2, and D3 (DRD1, 2, and 3) and the effect of risperidone treatment. The summary odds ratio (OR) and weighted mean difference (WMD) in a random-effects model were used to measure these relationships.
RESULTS
Twelve studies involving 24 SNPs were included. DRD2 (Ser311Cys, rs1801028 Ser/Ser) significantly lowered the improvement rate (determined by the PANSS score) unlike Ser/Cys (WMD: -11.58, 95% CI: -17.35 to -5.18). For Asian patients, A241G (rs1799978) AA carriers showed greater improvement after risperidone therapy (P < 0.05). The polymorphisms of 141C Ins/Del (rs1799732), T939C (rs6275), rs6277, and TaqID (rs1800498) may also influence the treatment effect. TaqIA (rs1800497) and TaqIB (rs17294542) were not associated with the rate of response to risperidone. DRD3 was not associated with an improvement in the PANSS total score; however, Ser9Gly might be related to a change in negative symptoms. No significant effect of DRD1 (rs5326, rs4867798, rs4532, and rs11749676) was found.
CONCLUSIONS
Our result supported the hypothesis that DRD2 affected risperidone treatment. DRD1 had no significant effect on the response to risperidone, whereas DRD3 might be associated with an improvement in negative symptoms. Larger observational studies are warranted to verify these findings and identify other genetic factors involved.
Topics: Antipsychotic Agents; Humans; Pharmacogenomic Variants; Polymorphism, Single Nucleotide; Receptors, Dopamine D1; Receptors, Dopamine D2; Receptors, Dopamine D3; Risperidone; Schizophrenia; Treatment Outcome
PubMed: 30103286
DOI: 10.1111/bcpt.13111 -
Journal of Diabetes and Metabolic... Dec 2023The Dopamine-2 receptor agonists, Bromocriptine and Cabergoline, were originally introduced for prolactinomas, pituitary tumors, and parkinson's disease but have... (Review)
Review
BACKGROUND
The Dopamine-2 receptor agonists, Bromocriptine and Cabergoline, were originally introduced for prolactinomas, pituitary tumors, and parkinson's disease but have glucose-lowering effects. This paper systematically reviewed the significance of their effects on lowering blood glucose level and conducted a comprehensive systematic search to identify relevant clinical trials of dopamine 2 agonists on glycated hemoglobin (HbA1c) and fasting blood sugar (FBS).
METHOD
We conducted a systematic review search in the databases (PubMed, Google Scholar, Cochrane Library, Registers, and Citations) until November 30, 2022, using the PRISMA 2020 statement. The Oxford quality score (Jadad score) was used to assess the study's quality. The present study protocol was registered on the PROSPERO database with ID: CRD42023389582. The study included studies with full abstracts, predefined doses, clear interventions, and blood glucose measurements.
RESULT
Data were synthesized from 23 clinical studies that recruited 6125 study subjects. The pooled effect analysis of the clinical trials revealed that dopamine 2 agonists improved HbA1c [SMD = -1.26; 95% CI (-1.60, -0.93), < .00001], and FBS [SMD = -1.84; 95% CI (-2.61, -1.07), < .00001]. Each drug's pooled effect analysis indicates bromocriptine significantly improved HbA1c [SMD = -1.25; 95% CI (-1.64, -0.87), < .00001] and FBS [SMD = -1.90; 95% CI (-2.79, -1.01), < .00001] and similarly, cabergoline significantly improved HbA1c [SMD = -1.29; 95% CI (-1.96, -0.62), < .00001] and FBS [SMD = -1.62; 95% CI (-2.82, -0.41), < .00001]. The pooled and individual analyses demonstrated that dopamine 2 agonists have a significant ability to lower blood glucose levels in clinical studies.
CONCLUSION
This study shows that dopamine 2 agonists significantly lowered FBS and HbA1c levels without causing severe negative effects. Even though the results are promising, additional research is necessary to establish the appropriate antihyperglycemic dosage, frequency of daily use, side effects, and potential product interactions when employing dopamine 2 receptor agonists for their antihyperglycemic effect.
PubMed: 37975084
DOI: 10.1007/s40200-023-01230-4 -
Parkinsonism & Related Disorders Sep 2023The human immunodeficiency virus (HIV) causes movement disorders in persons living with HIV (PLH). (Review)
Review
BACKGROUND
The human immunodeficiency virus (HIV) causes movement disorders in persons living with HIV (PLH).
OBJECTIVES AND METHODS
We conducted a systematic review on the spectrum of movement disorders in PLH using standard terms for each of the phenomenologies and HIV.
RESULTS
Movement disorders in PLH were commonly attributed to opportunistic infections (OI), dopamine receptor blockade reactions, HIV-associated dementia (HAD), presented during seroconversion, developed due to drug reactions or antiretroviral therapy (ART) itself and lastly, movement disorders occurred as a consequence of the HIV-virus. Parkinsonism in ART naïve PLH was associated with shorter survival, however when Parkinsonism presented in PLH on ART, the syndrome was indistinguishable from Idiopathic Parkinson's disease and responded to therapy. Tremor was often postural due to HAD, drugs or OI. Generalized chorea was most frequent in HIV encephalopathy and toxoplasmosis gondii caused most cases of hemichorea. Ataxia was strongly associated with JCV infection, ART efavirenz toxicity or due to HIV itself. Dystonia was reported in HAD, secondary to drugs and atypical facial dystonias. Both cortical/subcortical and segmental/spinal origin myoclonus were noted mainly associated with HAD. In patients with HIV related opsoclonus-myoclonus-ataxia-syndrome, seroconversion illness was the commonest cause of followed by IRIS and CSF HIV viral escape phenomenon.
CONCLUSIONS
Aetiology of movement disorders in PLH depend on the treatment state. Untreated, PLH are prone to develop OI and HAD and movement disorders. However, as the number of PLH on ART increase and survive longer, the frequency of ART and non-AIDS related complications are likely to increase.
Topics: Humans; HIV; Myoclonus; Movement Disorders; HIV Infections; Parkinson Disease; Parkinsonian Disorders; Ataxia
PubMed: 37532621
DOI: 10.1016/j.parkreldis.2023.105774 -
Journal of Geriatric Psychiatry and... Sep 2022Orthostatic hypotension (OH) is multifactorial in Parkinson's disease (PD). Antiparkinsonian medication can contribute to OH, leading to increased risk of falls,... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Orthostatic hypotension (OH) is multifactorial in Parkinson's disease (PD). Antiparkinsonian medication can contribute to OH, leading to increased risk of falls, weakness and fatigue.
METHODS
We conducted a systematic review and meta-analysis of randomised controlled trials (RCTs) of antiparkinsonian drugs associated with OH as an adverse effect, compared to placebo. We searched EMBASE, MEDLINE and Web of Science databases until November 2020. Analysis used fixed-effects models and the GRADE tool to rate quality of evidence. Meta-analysis was performed if 3 or more studies of a drug group were available.
RESULTS
Twenty-one RCTs including 3783 patients were included comparing 6 PD drug groups to placebo (MAO-B inhibitors, dopamine agonists, levodopa, COMT inhibitors, levodopa and adenosine receptor antagonists). OH was recorded as an adverse event or measurement of vital signs, without further specification on how this was defined or operationalised. Meta-analysis was performed for MAO-B inhibitors and dopamine agonists, as there were 3 or more studies for these drug groups. In this analysis, compared with placebo, neither MAO-B inhibitors or dopamine agonists were associated with increased risk of OH, (OR 2.28 [95% CI:0.81-6.46]), (OR 1.39 [95% CI:0.97-1.98]).
CONCLUSIONS
Most studies did not specifically report OH, or reporting of OH was limited, including how and when it was measured. Furthermore, studies specifically reporting OH included participants that were younger than typical PD populations without multimorbidity. Future trials should address this, for example,, by including individuals over the age of 75, to improve estimations of how antiparkinsonian medications affect risk of OH.
Topics: Antiparkinson Agents; Dopamine Agonists; Humans; Hypotension, Orthostatic; Levodopa; Monoamine Oxidase; Parkinson Disease
PubMed: 34964392
DOI: 10.1177/08919887211060017 -
Frontiers in Aging Neuroscience 2019The dopaminergic system has been associated with the progression of Alzheimer's disease. But previous studies found inconsistent results regarding the relationship...
The dopaminergic system has been associated with the progression of Alzheimer's disease. But previous studies found inconsistent results regarding the relationship between Alzheimer's disease and dopamine when looking at dopamine receptor concentrations. The aim of this review was to synthesize, using a random-effects model of meta-analysis, the link between the dopaminergic system and Alzheimer's disease. A detailed analysis protocol was registered at the PROSPERO database prior to data extraction (CRD42018110798). Electronic databases of PubMed, Embase, Web of Science, and Psyc-ARTICLES were searched up to December 2018 for studies that examined dopamine and dopamine receptors in relation to Alzheimer's disease. Standardized mean differences (SMD) were calculated to assess group differences in the levels of dopaminergic neurometabolites. Seventeen studies met the eligibility criteria. Collectively, they included 512 patients and 500 healthy controls. There were significantly lower levels of dopamine in patients with Alzheimer's disease compared with controls (SMD = -1.56, 95% CI: -2.64 to -0.49). In addition, dopamine 1 receptor (SMD = -5.05, 95% CI: -6.14 to -3.97) and dopamine 2 receptor (SMD = -1.13, 95% CI: -1.52 to -0.74) levels were decreased in patients with Alzheimer's disease compared with controls. The results of network meta-analysis indicated that the rank of correlation with Alzheimer's disease from highest to lowest was dopamine (0.74), dopamine 2 receptor (0.49), dopamine 3 receptor (0.46), dopamine 4 receptor (0.33), dopamine 5 receptor (0.31), and dopamine 1 receptor (0.64). Overall, decreased levels of dopaminergic neurotransmitters were linked with the pathophysiology of Alzheimer's disease. Nonetheless, there is a clear need for more prospective studies to validate these hypotheses.
PubMed: 31354471
DOI: 10.3389/fnagi.2019.00175 -
Psychopharmacology Feb 2024Dopamine antagonists induce dopamine receptor supersensitivity. This may manifest in late-appearing movement disorders (tardive dyskinesia (TD). VMAT-2 inhibitors reduce... (Meta-Analysis)
Meta-Analysis Review
RATIONALE
Dopamine antagonists induce dopamine receptor supersensitivity. This may manifest in late-appearing movement disorders (tardive dyskinesia (TD). VMAT-2 inhibitors reduce dopaminergic transmission but have limited activity at postsynaptic receptors and so may have antipsychotic activity with lower risk of tardive dyskinesia.
METHODS
We conducted a systematic database search from inception to September 2022 for articles describing the use of VMAT-2 inhibitors in psychosis. Inclusion criteria were as follows: Population: adults diagnosed with psychosis or schizophrenia; Intervention: treatment with tetrabenazine, deutetrabenazine or valbenazine; Comparison: comparison with placebo or/and antipsychotic drug; Outcomes: with efficacy outcomes (e.g. Brief Psychiatric Rating Scale (BPRS) change or clinician assessment) and adverse effects ratings (e.g. rating scale or clinician assessment or dropouts); and Studies: in randomised controlled trials and non-randomised studies.
RESULTS
We identified 4892 records relating to VMAT-2 inhibitor use of which 5 (173 participants) met our a priori meta-analysis inclusion criteria. VMAT-2 inhibitors were more effective than placebo for the outcome 'slight improvement' (risk ratio (RR) = 1.77 (95% CI 1.03, 3.04)) but not for 'moderate improvement' (RR 2.81 (95% CI 0.27, 29.17). VMAT-2 inhibitors were as effective as active comparators on both measures for-'slight improvement' (RR 1.05 (95% CI 0.6, 1.81)) and 'moderate improvement' (RR 1.11 (95% CI 0.51, 2.42). Antipsychotic efficacy was also suggested by a narrative review of 37 studies excluded from the meta-analysis.
CONCLUSIONS
VMAT-2 inhibitors may have antipsychotic activity and may offer promise for treatment of psychosis with the potential for a reduced risk of TD.
Topics: Adult; Humans; Antipsychotic Agents; Psychotic Disorders; Schizophrenia; Tardive Dyskinesia; Tetrabenazine; Vesicular Monoamine Transport Proteins
PubMed: 38238580
DOI: 10.1007/s00213-023-06488-3 -
Translational Psychiatry Feb 2018Schizophrenia is a debilitating neuropsychiatric illness that is characterized by positive, negative, and cognitive symptoms. Research over the past two decades suggests... (Review)
Review
Schizophrenia is a debilitating neuropsychiatric illness that is characterized by positive, negative, and cognitive symptoms. Research over the past two decades suggests that the nociceptin receptor system may be involved in domains affected in schizophrenia, based on evidence aligning it with hallmark features of the disorder. First, aberrant glutamatergic and striatal dopaminergic function are associated with psychotic symptoms, and the nociceptin receptor system has been shown to regulate dopamine and glutamate transmission. Second, stress is a critical risk factor for first break and relapse in schizophrenia, and evidence suggests that the nociceptin receptor system is also directly involved in stress modulation. Third, cognitive deficits are prevalent in schizophrenia, and the nociceptin receptor system has significant impact on learning and working memory. Last, reward processing is disrupted in schizophrenia, and nociceptin signaling has been shown to regulate reward cue salience. These findings provide the foundation for the involvement of the nociceptin receptor system in the pathophysiology of schizophrenia and outline the need for future research into this system.
Topics: Cognitive Dysfunction; Humans; Receptors, Opioid; Reward; Schizophrenia; Stress, Psychological; Nociceptin Receptor
PubMed: 29391391
DOI: 10.1038/s41398-017-0080-8