Update Lessons from PET Imaging Part II: A Systematic Critical Review on Therapeutic Plasma Concentrations of Antidepressants.

BACKGROUND: Compared with antipsychotics, the relationship between antidepressant blood (plasma or serum) concentrations and target engagement is less well-established. METHODS: We have discussed the literature on the relationship between plasma concentrations of antidepressant drugs and their target occupancy. Antidepressants reviewed in this work are citalopram, escitalopram, fluoxetine, fluvoxamine, paroxetine, sertraline, venlafaxine, duloxetine, milnacipran, tricyclic antidepressants (amitriptyline, nortriptyline, and clomipramine), bupropion, tranylcypromine, moclobemide, and vortioxetine. Four electronic databases were systematically searched. RESULTS: We included 32 articles published 1996-2022. A strong relationship between serotonin transporter (SERT) occupancy and drug concentration is well established for selective serotonin reuptake inhibitors. Lower limits of recommended therapeutic reference ranges largely corroborate with the findings from positron emission tomography studies (80% SERT occupancy). Only a few novel studies have investigated alternative targets, that is, norepinephrine transporters (NETs), dopamine transporters (DATs), or monoamine oxidase A (MAO-A). For certain classes of drugs, positron emission tomography study data are inconclusive. Low DAT occupancy after bupropion treatment speculates its discussed mechanism of action. For MAO inhibitors, a correlation between drug concentration and MAO-A occupancy could not be established. CONCLUSIONS: Neuroimaging studies are critical in TDM-guided therapy for certain antidepressants, whereas for bupropion and MAO inhibitors, the available evidence offers no further insight. Evidence for selective serotonin reuptake inhibitors is strong and justifies a titration toward suggested ranges. For SNRIs, duloxetine, and venlafaxine, NETs are sufficiently occupied, well above the SERT efficacy threshold. For these drugs, a titration toward higher concentrations (within the recommended range) should be considered in case of no response at lower concentrations.

Update Lessons from Positron Emission Tomography Imaging Part I: A Systematic Critical Review on Therapeutic Plasma Concentrations of Antipsychotics.

BACKGROUND: Positron emission tomography (PET) and single photon emission tomography (SPECT) of molecular drug targets (neuroreceptors and transporters) provide essential information for therapeutic drug monitoring-guided antipsychotic drug therapy. The optimal therapeutic windows for D 2 antagonists and partial agonists, as well as their proposed target ranges, are discussed based on an up-to-date literature search. METHODS: This part I of II presents an overview of molecular neuroimaging studies in humans and primates involving the target engagement of amisulpride, haloperidol, clozapine, aripiprazole, olanzapine, quetiapine, risperidone, cariprazine, and ziprasidone. The systemic review particularly focused on dopamine D 2 -like and 5-HT 2A receptors. Target concentration ranges were estimated based on receptor occupancy ranges that relate to clinical effects or side effects (ie, extrapyramidal side effects). In addition, findings for other relevant receptor systems were included to further enrich the discussion. RESULTS: The reported reference ranges for aripiprazole and clozapine align closely with findings from PET studies. Conversely, for haloperidol, risperidone, and olanzapine, the PET studies indicate that a lowering of the previously published upper limits would be necessary to decrease the risk of extrapyramidal side effect. CONCLUSIONS: Molecular neuroimaging studies serve as a strong tool for defining target ranges for antipsychotic drug treatment and directing therapeutic drug monitoring.

Treatment with psychedelics is psychotherapy: beyond reductionism.

Treatment of psychiatric disorders with psychedelic substances represents one of the most promising current treatment approaches in psychiatry. Since its inception in the 1950s, therapy with psychedelics has been conceptualised as psychedelic-assisted psychotherapy-ie, a form of psychotherapy that uses the profound biological effects of this class of substances as a catalyst for changing thinking, emotions, and behaviour. In this view, the psychotherapy component of the treatment is considered as being of the utmost importance for both the safety and efficacy of the therapy. This conceptualisation has been challenged by the idea that the latest clinical studies suggest that the potential therapeutic effects of psychedelics must be attributed solely to the substance itself, with no role for psychotherapy. Here, accompaniment by therapists is understood as mere psychological support, to maintain the safety of the substance administration. In this Personal View, we contrast these two views and argue that the characterisation of treatment with psychedelics as a biological intervention (with psychological support as a purely safety-related component) represents an outdated and reductionistic dualism that has dominated psychiatric treatment and research for far too long. This discussion has important implications for the study and the regulation of these compounds.

[Are psychedelics fast acting antidepressant agents?] / Sind Psychedelika schnell wirksame Antidepressiva?

BACKGROUND: Psychedelics, such as psilocybin represent one of the most promising current therapeutic approaches in psychiatry. OBJECTIVE: Psychedelics seem to have not only potent antidepressant effects. Do they also work particularly quickly, i.e. within one day? MATERIAL AND METHODS: The available literature on clinical studies of psychedelics in depressive syndromes is presented both from the period up to the prohibition of these substances in the late 1960s as well as after the resumption of research in the 2000s. One focus is the speed of onset of antidepressant action. RESULTS: Only the clinical studies published since 2016 that meet modern methodological standards have also systematically examined the speed of the antidepressant onset of action. The published studies, which were almost exclusively carried out with psilocybin, so far show small sample sizes (the total number of patients with depression treated in published clinical studies is < 200) and some of them have methodological weaknesses; however, they suggest a pronounced and very rapid onset of action within one day for depression, treatment-resistant depression and depression in the context of life-threatening cancer. CONCLUSION: The available studies indicate a potent, rapid onset and in many cases long-lasting antidepressant effect over several months. The currently conducted studies with three-digit patient numbers will provide final information about the potential of psilocybin for depression.

Brief Report: Specificity of Interpersonal Synchrony Deficits to Autism Spectrum Disorder and Its Potential for Digitally Assisted Diagnostics.

Reliably diagnosing autism spectrum disorders (ASD) in adulthood poses a challenge to clinicians due to the absence of specific diagnostic markers. This study investigated the potential of interpersonal synchrony (IPS), which has been found to be reduced in ASD, to augment the diagnostic process. IPS was objectively assessed in videos of diagnostic interviews in a representative referral population from two specialized autism outpatient clinics. In contrast to the current screening tools that could not reliably differentiate, we found a significant reduction of IPS in interactions with individuals later diagnosed with ASD (n = 16) as opposed to those not receiving a diagnosis (n = 23). While these findings need to be validated in larger samples, they nevertheless underline the potential of digitally-enhanced diagnostic processes for ASD.