[Psychedelic psychiatry]. / Psykedelisk psykiatri ­ det finns anledning att vara optimistisk.

In the last 20 years there has been an increased interest in research on psychedelic compounds for treatment of psychiatric conditions such as depression, anxiety and substance use disorders. Despite existing treatments being efficacious for many patients, this is not the case for up to a third of the patients with depression. Additionally, treatments are often long and associated with side effects. This review focuses on the psychedelic compound psilocybin, a serotonin-2A-receptor agonist that has been seen to reduce depression and anxiety in patients after administration of only a single dose, with effects lasting several weeks. Recent findings from phase II studies suggest that psilocybin treatment for depression is safe and efficacious. A phase III study is currently recruiting. Whether psychedelics will become a part of standard healthcare remains to be seen, but findings do give rise to cautious optimism.

Utilization of antidepressants, anxiolytics, and hypnotics during the COVID-19 pandemic.

Since the onset of the COVID-19 pandemic, there have been concerns over the mental health impact of COVID-19. This is a review of the utilization of antidepressants, anxiolytics, and hypnotics since the COVID-19 pandemic was declared on March the 11th 2020. A number of reports so far have been based on large prescription databases for administrative use at the national or regional level, but mainly in high-income countries. We found studies reporting increased prescription rates of antidepressants, anxiolytics, and hypnotics during March 2020, which has been interpreted as hoarding of such medications. In the following months, most studies of antidepressant prescription rates did not display a clear pattern of change compared with prepandemic trends. In later phases of the pandemic small increases in utilization of antidepressants, with higher than predicted prescription rates, have been the most consistent finding, especially in youth. In most high-income countries, there were increasing trends in utilization of antidepressants also before 2020, which needs to be considered when estimating utilization during the pandemic, whereas for anxiolytics and hypnotics, the prepandemic patterns of prescriptions were more varying. Overall, after March 2020 we could not find any distinct changes in the utilization of anxiolytics and hypnotics during the COVID-19 pandemic. Most studies did not contain information about the prevalence of indicated psychiatric disorders in the studied populations. More studies are needed about the long-term effects of COVID-19, particularly regarding utilization of antidepressants. Research relating antidepressant utilization with the prevalence of major depression and anxiety disorders would promote a better understanding of how well antidepressant prescription rates reflect the needs of the population.

Response to electroconvulsive therapy in treatment-resistant depression: nationwide observational follow-up study.

BACKGROUND: Previous studies have not investigated response rates after electroconvulsive therapy (ECT) in patients with non-psychotic treatment-resistant depression (TRD). AIMS: To assess and compare the response rate of ECT for patients with TRD and non-TRD, in a large and clinically representative patient sample. METHOD: Patients aged ≥18 years, who were treated for a unipolar, non-psychotic depressive episode with at least one ECT session as part of a first-time, index ECT series between 1 January 2011 and 31 December 2017 were included from the Swedish National Quality Register for ECT. Patients who had initiated a third consecutive trial of antidepressants or add-on medications before start of ECT were classified as having TRD. Patients not meeting criteria for TRD were classified as non-TRD. The main outcome was response to ECT according to the Clinical Global Impressions - Improvement Scale (CGI-I), scored as 1 or 2 ('very much' or 'much improved' after ECT, respectively). Logistic regression was used to compare outcome measures between TRD and non-TRD, adjusting for potential confounders. RESULTS: A total of 4244 patients were included. Of these, 1121 patients had TRD and 3123 patients had non-TRD. The CGI-I response rate was 65.9% in the TRD group compared with 75.9% in the non-TRD group (adjusted odds ratio 0.64, 95% CI 0.54-0.75). Older age and more severe depression were predictors of response in patients with TRD. CONCLUSIONS: A clear majority of patients with TRD, as well as patients with non-TRD, responded to ECT, although the response rate was somewhat lower for TRD.

Utilization of antidepressants, anxiolytics, and hypnotics during the COVID-19 pandemic in Scandinavia.

OBJECTIVE: To study patterns of antidepressant, anxiolytic, and hypnotic drug utilization in Denmark, Norway, and Sweden during the first year of the COVID-19 pandemic. METHODS: The monthly observed number of prescription fills of antidepressants, benzodiazepines and benzodiazepine-related hypnotics (BZ), and other anxiolytics and hypnotics (OAH) per population in 2020 were compared with predicted numbers based on analysis of covariance of prescription fills during 2015-2019. RESULTS: In March 2020, there was an increased number of prescription fills for antidepressants, anxiolytics, and hypnotics in youths and adults aged 20-59 years in Denmark, Norway, and Sweden. Antidepressant prescription fills increased between 13.5 % and 31.3 % at the end of 2020 in all age groups in Denmark and 17.4 % in youths in Norway. BZ drug prescription fills increased by 20.8 % at the end of 2020 in the 20-59 year age group in Denmark and decreased by 16.7 % in youths in Sweden. A general increase of prescription fills of OAH at the end of 2020 was observed in all countries (range 24.0-80.0 % in Denmark, 11.5-30.8 % in Norway, and 9.1-12.1 % in Sweden). Increases of prescription fills of OAH occurred earlier in Denmark. LIMITATIONS: Aggregated data with lack of information on indications. CONCLUSIONS: Peaks of utilization of antidepressants, anxiolytics, and hypnotics observed in March 2020 may reflect medication stock piling. Increased antidepressant drug utilization in Denmark and in Norwegian youths together with the general increase in OAH utilization in the Scandinavian countries in late 2020 may indicate an increase of symptoms of depression and anxiety, as well as disturbed sleep.

Associations Between Cognition and Serotonin 1B Receptor Availability in Healthy Volunteers: A [11C]AZ10419369 Positron Emission Tomography Study.

BACKGROUND: The serotonin system has been implicated in several psychiatric disorders. All major psychiatric disorders are associated with cognitive impairment, but treatment improving cognitive deficits is lacking, partly due to limited understanding of the neurobiology of cognitive functioning. Several markers for the serotonin system have been associated with cognitive functions. Our research group previously has reported a positive correlation between serotonin (5-HT1B) receptor availability in the dorsal brainstem and visuospatial memory in a pilot study of healthy individuals. Here, we aim to replicate our previous finding in a larger group of healthy volunteers as well as to investigate putative associations between 5-HT1B receptor availability and other cognitive domains. METHODS: Forty-three healthy individuals were examined with positron emission tomography using the 5-HT1B receptor radioligand [11C]AZ10419369 and a visuospatial memory test to replicate our previous finding as well as tests of verbal fluency, cognitive flexibility, reaction time, and planning ability to explore other domains potentially associated with the serotonin system. RESULTS: Replication analysis revealed no statistically significant association between 5-HT1B receptor availability in the dorsal brainstem and visuospatial memory performance. Exploratory analyses showed age-adjusted correlations between 5-HT1B receptor availability in whole brain gray matter and specific brain regions, and number of commission errors, reaction time, and planning ability. CONCLUSIONS: Higher 5-HT1B receptor availability was associated with more false-positive responses and faster reaction time but lower performance in planning and problem-solving. These results corroborate previous research supporting an important role of the serotonin system in impulsive behavior and planning ability.

International pooled patient-level meta-analysis of ketamine infusion for depression: In search of clinical moderators.

Depression is disabling and highly prevalent. Intravenous (IV) ketamine displays rapid-onset antidepressant properties, but little is known regarding which patients are most likely to benefit, limiting personalized prescriptions. We identified randomized controlled trials of IV ketamine that recruited individuals with a relevant psychiatric diagnosis (e.g., unipolar or bipolar depression; post-traumatic stress disorder), included one or more control arms, did not provide any other study-administered treatment in conjunction with ketamine (although clinically prescribed concurrent treatments were allowable), and assessed outcome using either the Montgomery-Åsberg Depression Rating Scale or the Hamilton Rating Scale for Depression (HRSD-17). Individual patient-level data for at least one outcome was obtained from 17 of 25 eligible trials [pooled n = 809]. Rates of participant-level data availability across 33 moderators that were solicited from these 17 studies ranged from 10.8% to 100% (median = 55.6%). After data harmonization, moderators available in at least 40% of the dataset were tested sequentially, as well as with a data-driven, combined moderator approach. Robust main effects of ketamine on acute [~24-hours; ß*(95% CI) = 0.58 (0.44, 0.72); p < 0.0001] and post-acute [~7 days; ß*(95% CI) = 0.38 (0.23, 0.54); p < 0.0001] depression severity were observed. Two study-level moderators emerged as significant: ketamine effects (relative to placebo) were larger in studies that required a higher degree of previous treatment resistance to federal regulatory agency-approved antidepressant medications (≥2 failed trials) for study entry; and in studies that used a crossover design. A comprehensive data-driven search for combined moderators identified statistically significant, but modest and clinically uninformative, effects (effect size r ≤ 0.29, a small-medium effect). Ketamine robustly reduces depressive symptoms in a heterogeneous range of patients, with benefit relative to placebo even greater in patients more resistant to prior medications. In this largest effort to date to apply precision medicine approaches to ketamine treatment, no clinical or demographic patient-level features were detected that could be used to guide ketamine treatment decisions.Review Registration: PROSPERO Identifier: CRD42021235630.

In vivo correlation of serotonin transporter and 1B receptor availability in the human brain: a PET study.

Synaptic serotonin levels in the brain are regulated by active transport into the bouton by the serotonin transporter, and by autoreceptors, such as the inhibitory serotonin (5-HT) 1B receptor which, when activated, decreases serotonin release. Animal studies have shown a regulatory link between the two proteins. Evidence of such coupling could translate to an untapped therapeutic potential in augmenting the effect of selective serotonin reuptake inhibitors through pharmacological modulation of 5-HT1B receptors. Here we will for the first time in vivo examine the relationship between 5-HT1B receptors and serotonin transporters in the living human brain. Seventeen healthy individuals were examined with PET twice, using the radioligands [11C]AZ10419369 and [11C]MADAM for quantification of the 5-HT1B receptor and the 5-HT transporter, respectively. The binding potential was calculated for a set of brain regions, and the correlations between the binding estimates of the two radioligands were studied. [11C]AZ10419369 and [11C]MADAM binding was positively correlated in all examined brain regions. In most cortical regions the correlation was strong, e.g., frontal cortex, r(15) = 0.64, p = 0.01 and parietal cortex, r(15) = 0.8, p = 0.0002 while in most subcortical regions, negligible correlations was observed. Though the correlation estimates in cortex should be interpreted with caution due to poor signal to noise ratio of [11C]MADAM binding in these regions, it suggests a link between two key proteins involved in the regulation of synaptic serotonin levels. Our results indicate a need for further studies to address the functional importance of 5-HT1B receptors in treatment with drugs that inhibit serotonin reuptake.

Serotonin 1B receptor density mapping of the human brainstem using positron emission tomography and autoradiography.

The serotonin 1B (5-HT1B) receptor has lately received considerable interest in relation to psychiatric and neurological diseases, partly due to findings based on quantification using Positron Emission Tomography (PET). Although the brainstem is an important structure in this regard, PET radioligand binding quantification in brainstem areas often shows poor reliability. This study aims to improve PET quantification of 5-HT1B receptor binding in the brainstem.Volumes of interest (VOIs) were selected based on a 3D [3H]AZ10419369 Autoradiography brainstem model, which visualized 5-HT1B receptor distribution in high resolution. Two previously developed VOI delineation methods were tested and compared to a conventional manual method. For a method based on template data, a [11C]AZ10419369 PET template was created by averaging parametric binding potential (BPND) images of 52 healthy subjects. VOIs were generated based on a predefined volume and BPND thresholding and subsequently applied to test-retest [11C]AZ10419369 parametric BPND images of 8 healthy subjects. For a method based on individual subject data, VOIs were generated directly on each individual parametric image.Both methods showed improved reliability compared to a conventional manual VOI. The VOIs created with [11C]AZ10419369 template data can be automatically applied to future PET studies measuring 5-HT1B receptor binding in the brainstem.

Health care utilisation in treatment-resistant depression: a Swedish population-based cohort study.

OBJECTIVE: To investigate the health care utilisation (HCU) among patients with treatment-resistant depression (TRD) compared to patients with depression not meeting TRD criteria. METHODS: Nationwide Swedish registers were used to identify patients 18-69 years old with incident depression and antidepressant treatment. Patients were followed prospectively and defined as having TRD at start of the third distinct consecutive treatment episode. Each of the 16,329 identified TRD patients were matched with five comparators with depression not meeting criteria for TRD. Main outcome measure was total number of inpatient days and outpatient visits, and secondary outcome was HCU in connection with a main diagnosis of depression or suicide attempt. RESULTS: TRD patients had a significantly higher risk of all-cause inpatient care than comparators (first year adjusted risk ratio [aRR] 3.03 [95%CI 3.01-3.05], years 1-3 aRR 2.15 [2.13-2.16]). This was more pronounced when the main diagnosis was depression (first year aRR 4.41 [4.36-4.45]), and after suicide attempt (first year aRR 4.43 [4.26-4.60]). Outpatient visits were also markedly more frequent for patients with TRD (first year aRR 2.05 [2.03-2.07]). Higher HCU among TRD patients persisted throughout follow-up. CONCLUSIONS: Patients with TRD may have a twofold to fourfold higher HCU than other patients with depression.KEYPOINTSThis register-based prospective study investigated health care utilisation (HCU) among patients with treatment-resistant depression (TRD) compared to other patients with depression.Patients with TRD had a two to fourfold higher HCU regarding all measured outcomes, including inpatient hospital days and outpatient visits.The elevated HCU persisted for more than three years, although decreasing gradually. This should correspond to increased costs and individual burden for patients with TRD.

Plasma Levels of Brain-Derived Neurotrophic Factor and S100B in Relation to Antidepressant Response to Ketamine.

BACKGROUND: Evidence demonstrates that brain-derived neurotrophic factor (BDNF) and S100 calcium-binding protein B (S100B) have a pivotal role in the pathogenesis of major depressive disorder (MDD) and they are proposed as predictors of antidepressant response. Ketamine produces rapid antidepressant effects in MDD and pre-clinical studies suggest the necessity of increased BDNF levels for the antidepressant action of ketamine. However, studies observing the change of blood BDNF levels after ketamine intervention are inconsistent and studies about the role of plasma S100B in ketamine administration in MDD patients are lacking. METHOD: We evaluated mature BDNF (mBDNF), S100B levels in plasma and their associations with depression severity in 30 Selective Serotonin Reuptake Inhibitor (SSRI)-resistant MDD patients enrolled in a randomized controlled trial of ketamine compared (n = 20) to a placebo (n = 10) control (saline). Severity of depression was assessed using the Montgomery-Åsberg Depression Rating Scale (MADRS). RESULTS: Plasma mBDNF and S100B were not significantly changed after 1-2 days of single ketamine compared to placebo. Plasma mBDNF and S100B levels did not significantly differ in responders compared to non-responders of ketamine treatment. The change of plasma mBDNF levels was positively correlated with the improvement of MADRS score after 1-2 weeks of open-label ketamine treatment (rho = 0.495, p = 0.031), though this change did not survive correction for multiple comparisons. CONCLUSION: These findings do not support the hypothesis that ketamine treatment increases BDNF plasma levels in MDD patients. No effect of ketamine treatment on S100B plasma levels was seen.

A positron emission tomography study of the serotonin1B receptor effect of electroconvulsive therapy for severe major depressive episodes.

BACKGROUND: Electroconvulsive therapy (ECT) is an effective treatment for depressive disorders, although its molecular mechanism of action is unknown. The serotonin 1B (5-HT1B) receptor is a potential target for treatment of depression and low 5-HT1B receptor binding in limbic regions has been reported in previous positron emission tomography (PET) studies of depression. METHODS: The objective of this longitudinal PET study was to examine the effect of ECT for depression on 5-HT1B receptor binding. Fifteen hospitalized patients with major depressive episodes were examined with PET and the 5-HT1B receptor selective radioligand [11C]AZ10419369, before and after ECT. Fifteen controls matched for age and sex were examined. Limbic regions with previously reported low 5-HT1B receptor binding in depression and a dorsal brain stem region were selected. RESULTS: Thirteen patients completed the study according to protocol. Eleven out of thirteen patients responded to ECT. 5-HT1B receptor binding in hippocampus increased with 30 % after ECT (p=0.021). Using linear mixed effects modelling, we observed increases in 5-HT1B receptor binding following ECT with a moderate to large effect size, which did not differ significantly between regions. In an exploratory analysis, strong correlations between changes in 5-HT1B receptor binding and agitation scores on the Hamilton Depression Rating Scale after ECT were observed. LIMITATIONS: Albeit representative of a PET study, the sample size is still small and there are potential confounding effects of medication. CONCLUSIONS: Increased 5-HT1B receptor binding was observed following ECT for depression, corresponding to previous findings of increased 5-HT1B receptor binding in hippocampus after rapid acting ketamine for treatment resistant depression.

P11 (S100A10) as a potential predictor of ketamine response in patients with SSRI-resistant depression.

BACKGROUND: Ketamine can act as antidepressant in patients with major depressive disorder (MDD) who are treatment-resistant. P11 has been implicated in ketamine's mechanism of action and proposed as biomarker for treatment response to other antidepressants. This study explores the effect of ketamine on peripheral p11 and the potential role for p11 as response marker for ketamine treatment. METHODS: Thirty Selective Serotonin Reuptake Inhibitor resistant MDD patients were randomized to either 0.5 mg/kg ketamine or placebo intravenous treatment. Using multicolor Flow Cytometry, peripheral p11 levels were measured before and 1-2 days after treatment. RESULTS: P11 levels were decreased within the ketamine group in both cytotoxic T cell and T helper cells populations, although this did not significantly differ from changes seen in the placebo group. Baseline p11 levels in cytotoxic T cells were significantly correlated with antidepressant response to ketamine treatment. LIMITATIONS: This study was part of a larger study examining the effect of ketamine on the serotonin system in MDD patients, therefore the number of study subjects was limited to that of the primary study. CONCLUSIONS: High baseline p11 levels in cytotoxic T cells were associated with a stronger reduction of depressive symptoms in MDD patients after ketamine treatment. Future studies should confirm if peripheral p11 levels could be used as a predictor of ketamine treatment response.

The effect of anaesthetic dose on response and remission in electroconvulsive therapy for major depressive disorder: nationwide register-based cohort study.

BACKGROUND: Electroconvulsive therapy (ECT) is a safe and effective treatment for major depressive disorder (MDD). ECT treatment effect relies on induced generalised seizures. Most anaesthetics raise the seizure threshold and shorten seizure duration. There are no conclusive studies on the effect of anaesthetic dose on response and remission rates with ECT for MDD. AIMS: We aimed to examine the effect of different dose intervals of anaesthetics on response and remission after ECT for MDD. METHOD: We conducted a nationwide cohort study, using data from Swedish registers. Low-, medium- and high-dose intervals, adjusted for age and gender, were constructed for each anaesthetic drug. Response and remission were measured with the Clinical Global Impression - Severity and Improvement scales (CGI-I and CGI-S), and a self-rated version of the Montgomery-Åsberg Depression Rating Scale (MADRS-S). Logistic regression models were used to calculate adjusted odds ratios for response and remission rates. RESULTS: The study included 7917 patients who received ECT for MDD during 2012-2018. Patients were given either thiopental (64.1%) or propofol (35.9%). Low-dose intervals of anaesthetics were associated with increased rates of response (CGI-I: odds ratio 1.22, 95% CI 1.07-1.40, P = 0.004; MADRS-S: odds ratio 1.31, 95% CI 1.09-1.56, P = 0.004) and remission (CGI-S: odds ratio 1.37, 95% CI 1.17-1.60, P ≤ 0.001; MADRS-S: odds ratio 1.31, 95% CI 1.10-1.54, P = 0.002). CONCLUSIONS: We found improved treatment outcomes with low- compared with high-dose anaesthetic during ECT for MDD. To enhance treatment effect, deep anaesthesia during ECT for MDD should be avoided.

A randomized placebo-controlled PET study of ketamine´s effect on serotonin1B receptor binding in patients with SSRI-resistant depression.

The glutamate N-methyl-D-aspartate receptor antagonist ketamine has a rapid antidepressant effect. Despite large research efforts, ketamine's mechanism of action in major depressive disorder (MDD) has still not been determined. In rodents, the antidepressant properties of ketamine were found to be dependent on both the α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) and the serotonin (5-HT)1B receptor. Low 5-HT1B receptor binding in limbic brain regions is a replicated finding in MDD. In non-human primates, AMPA-dependent increase in 5-HT1B receptor binding in the ventral striatum (VST) has been demonstrated after ketamine infusion. Thirty selective serotonin reuptake inhibitor-resistant MDD patients were recruited via advertisement and randomized to double-blind monotherapy with 0.5 mg/kg ketamine or placebo infusion. The patients were examined with the 5-HT1B receptor selective radioligand [11C]AZ10419369 and positron emission tomography (PET) before and 24-72 h after treatment. 5-HT1B receptor binding did not significantly alter in patients treated with ketamine compared with placebo. An increase in 5-HT1B receptor binding with 16.7 % (p = 0.036) was found in the hippocampus after one ketamine treatment. 5-HT1B receptor binding in VST at baseline correlated with MDD symptom ratings (r = -0.426, p = 0.019) and with reduction of depressive symptoms with ketamine (r = -0.644, p = 0.002). In conclusion, reduction of depressive symptoms in MDD patients after ketamine treatment is correlated inversely with baseline 5-HT1B receptor binding in VST. Further studies examining the role of 5-HT1B receptors in the antidepressant mechanism of action of ketamine should be conducted, homing in on the 5-HT1B receptor as an MDD treatment response marker.

Electroconvulsive therapy decreases striatal dopamine transporter binding in patients with depression: A positron emission tomography study with [18F]FE-PE2I.

Electroconvulsive therapy (ECT) is an effective treatment for major depression. Previous studies suggested that dopaminergic neurotransmission plays a crucial role in the mechanism of the action of ECT. Since dopamine transporters (DAT) regulate extracellular dopamine concentration, DAT represents an interesting target for the study of the mechanism of action of ECT. Eight inpatients (7 patients with major depressive disorder and 1 patient with bipolar disorder with a DSM-IV diagnosis) received a series of 7-15(11.3±5.2) bilateral ECT sessions.The severity of symptoms was assessed using the 21-item Hamilton Depression Rating Scale (HDRS) and Clinical Global Impression-Severity (CGI-S). All patients were examined with [18F]FE-PE2I positron emission tomography (PET) at pre-ECT, after the 10th ECT, and at post-ECT. Striatal DAT-binding potential (BPND) of all patients was reduced, with an average change ratio of DAT-BPND of -13.1±5.6%. In the 2 cases with 15 ECT sessions, the ratio change of DAT-BPND after the 15th ECT was larger than that after the 10th ECT. Also, HDRS and CGI-S were reduced. These results indicate that the dopamine nervous system is part of themechanism of action of ECT.

Low dopamine transporter binding in the nucleus accumbens in geriatric patients with severe depression.

AIM: Dysfunction of dopaminergic neurons in the central nervous system is considered to be related to major depressive disorder (MDD). Especially, MDD in geriatric patients is characterized by anhedonia, which is assumed to be associated with reduced dopamine neurotransmission in the reward system. Dopamine transporter (DAT) is considered to reflect the function of the dopamine nerve system. However, previous DAT imaging studies using single photon emission computed tomography or positron emission tomography (PET) have shown inconsistent results. The radioligand [18 F]FE-PE2I for PET enables more precise evaluation of DAT availability. Hence, we aimed to evaluate the DAT availability in geriatric patients with MDD using [18 F]FE-PE2I. METHODS: Eleven geriatric patients with severe MDD and 27 healthy controls underwent PET with [18 F]FE-PE2I, which has high affinity and selectivity for DAT. Binding potentials (BPND ) in the striatum (caudate and putamen), nucleus accumbens (NAc), and substantia nigra were calculated. BPND values were compared between MDD patients and healthy controls. RESULTS: MDD patients showed significantly lower DAT BPND in the NAc (P = 0.009), and there was a trend of lower BPND in the putamen (P = 0.032) compared to controls. CONCLUSION: We found low DAT in the NAc and putamen in geriatric patients with severe MDD, which could be related to dysregulation of the reward system.

[11 C]raclopride positron emission tomography study of dopamine-D2/3 receptor binding in patients with severe major depressive episodes before and after electroconvulsive therapy and compared to control subjects.

AIM: The aim of the study was to test: (i) if D2 /D3 binding in three functional subsections of striatum is different in patients with severe major depressive episodes than in controls; and (ii) if this difference is normalized after electroconvulsive therapy (ECT). METHODS: Nine inpatients were examined with positron emission tomography (PET) and the radioligand [11 C]raclopride before and after an average of 8.4 ECT sessions. Treatment response was assessed using the Montgomery-Åsberg Depression Rating Scale. Nine age- and sex-matched controls were examined twice with PET and [11 C]raclopride. RESULTS: [11 C]raclopride binding was significantly lower in all three subsections of striatum in patients compared to controls (Cohen's dz , 1.14-1.68; P = 0.003-0.027). Montgomery-Åsberg Depression Ratings decreased significantly after ECT (P < 0.001; Cohen's dz , 2.9). ECT had no statistically significant effect on [11 C]raclopride binding, although post-ECT binding estimates were more similar to those obtained in controls in all subsections of striatum. CONCLUSION: Using PET and [11 C]raclopride, we found support for the notion that severe major depressive episodes are associated with significantly lower dopamine D2 /D3 binding in all three subsections of striatum compared to controls. We noted no significant effect on D2 /D3 binding in the patient group after response to ECT.

Validity and reliability of extrastriatal [11C]raclopride binding quantification in the living human brain.

[11C]raclopride is a well established PET tracer for the quantification of dopamine 2/3 receptors (D2/3R) in the striatum. Outside of the striatum the receptor density is up to two orders of magnitude lower. In contrast to striatal binding, the characteristics of extrastriatal [11C]raclopride binding quantification has not been thoroughly described. Still, binding data for e.g., neocortex is frequently reported in the scientific literature. Here we evaluate the validity and reliability of extrastriatal [11C]raclopride binding quantification. Two sets of healthy control subjects were examined with HRRT and [11C]raclopride: (i) To assess the validity of extrastriatal [11C]raclopride binding estimates, eleven subjects were examined at baseline and after dosing with quetiapine, a D2/3R antagonist. (ii) To assess test-retest repeatability, nine subjects were examined twice. Non displaceable binding potential (BPND) was quantified using the simplified reference tissue model with cerebellum as reference. Quetiapine dosing was associated with decrease in [11C]raclopride BPND in temporal cortex (18 ±â€¯17% occupancy) and thalamus (20 ±â€¯17%), but not in frontal cortex. Extrastriatal occupancy was lower than in putamen (51 ±â€¯4%). The mean absolute variation was 4-7% in the striatal regions, 17% in thalamus, and 13-59% in cortical regions. Our data indicate that [11C]raclopride PET, quantified using cerebellum as reference, is not a suitable tool to measure D2/3R in extrastriatal regions.

Less memory complaints with reduced stimulus dose during electroconvulsive therapy for depression.

BACKGROUND: Electroconvulsive therapy (ECT) is an effective treatment for depression, but there is risk of cognitive adverse events. This risk has been partially attributed to electrical charge, thus the optimal electrical stimulus dose is still under discussion. The aim of this study was to evaluate how the risk of subjective memory worsening was changed after lowering stimulus dose during ECT for patients with major depression. METHOD: A retrospective register-based intervention study of the effects of reduced electrical charges for patients receiving ECT for depression was conducted. The primary outcome was subjective memory worsening and the secondary outcome change in effect on depressive symptoms. RESULTS: A total of 154 patients were enrolled in the study (High dosage group: n = 57; Lower dosage group: n = 97). Subjective memory worsening after ECT occurred in 44% of patients in the high dosage group and in 25% of patients in the lower dosage group(p = 0.014). There was no significant between-group difference in the anti-depressive effect of ECT. LIMITATIONS: The study was register-based and the two groups were not randomized. A large portion of patients were initially excluded due to missing data in the register. The study lacks a long-term follow up. CONCLUSION: After implementing a change of treatment protocol, that lowered ECT stimulus doses from high to moderate, the occurrence of subjective memory worsening was significantly reduced without compromising treatment results.