Matteo Caloro

The role of memantine in the treatment of psychiatric disorders other than the dementias: A review of current preclinical and clinical evidence

Memantine, a non-competitive NMDA receptor antagonist approved for Alzheimer’s disease with a good safety profile, is increasingly being studied in a variety of non-dementia psychiatric disorders. We aimed to critically review relevant literature on the use of the drug in such disorders. We performed a PubMed search of the effects of memantine in animal models of psychiatric disorders and its effects in human studies of specific psychiatric disorders. The bulk of the data relates to the effects of memantine in major depressive disorder and schizophrenia, although more recent studies have provided data on the use of the drug in bipolar disorder as an add-on. Despite interesting preclinical data, results in major depression are not encouraging. Animal studies investigating the possible usefulness of memantine in schizophrenia are controversial; however, interesting findings were obtained in open studies of schizophrenia, but negative placebo-controlled, double-blind studies cast doubt on their validity. The effects of memantine in anxiety disorders have been poorly investigated, but data indicate that the use of the drug in obsessive-compulsive disorder and post-traumatic stress disorder holds promise, while findings relating to generalized anxiety disorder are rather disappointing. Results in eating disorders, catatonia, impulse control disorders (pathological gambling), substance and alcohol abuse/dependence, and attention-deficit hyperactivity disorder are inconclusive. In most psychiatric non-Alzheimer’s disease conditions, the clinical data fail to support the usefulness of memantine as monotherapy or add-on treatment However, recent preclinical and clinical findings suggest that add-on memantine may show antimanic and mood-stabilizing effects in treatment-resistant bipolar disorder.

An improved simple LC–MS/MS method for the measurement of serum aripiprazole and its major metabolite

BACKGROUND AND OBJECTIVES Current liquid chromatographic tandem mass spectrometry (LC-MS/MS) methods to measure serum levels of aripiprazole (Ar) and dehydroaripiprazole (DHAr) are sensitive, but difficult to use in a hospital context. We aimed to develop a rapid LC-MS/MS method allowing reliable level measurement in the presence of co-administered drugs, withdrawing samples from 22 patients with acute agitation receiving 9.75 mg aripiprazole IM injection. METHOD We developed a sensitive and selective HPLC-MS/MS method to measure serum Ar and DHAr levels in a hospital laboratory, requiring minimal sample preparation and inferior sample volume compared to previous LC-MS/MS methods. Analytes were separated on a reversed-phase HPLC (run-time, 10 min). A triple quadrupole tandem mass spectrometer was used for quantitative analysis in positive mode by a multiple reaction monitoring. Samples were drawn 2, 4, 6, and 24h post-injection. RESULTS Calibration curves (2-1000 ng/mL for Ar and 3.5-500 ng/mL for DHAr) were linear, with mean correlation coefficient >0.9998. Within- and between-day precision and accuracy were within 10%. Mean recovery was 95.2 ± 4.5% for Ar and 97.6 ± 7.2% for DHAr. Ar and DHAr peaks were not affected by other co-administered psychotropic drugs. CONCLUSION Our method measured Ar and DHAr concentrations reliably, simply and rapidly without employing many reagents, as currently existing methods.

The wnt pathway in mood disorders

Objectives: To review the evidence of the involvement of the Wnt signalling pathway in mood disorders and in the action of drugs used to treat these disorders. Methods: We performed a careful PubMed search using as keywords all possible terms relevant to the Wnt pathway and crossing them with each of four areas, i.e., developmental effects, behavioural effects, mood disorders, and drugs used in their treatment. Papers were selected on the basis of their content and their data used for discussion. Results: Neurodevelopmental and behavioural data point to the possibility of involvement of the Wnt pathway in the pathophysiology of mood disorders. Clinical and post-mortem data are not sufficient to corroborate a definite role for Wnt alterations in any mood disorder. Combining genetic and pharmacological data, we may state that glycogen synthase kinase is the key molecule in bipolar disorder, as it is connected with many other signalling pathways that were shown to be involved in mood disorders, while Wnt molecules in the hippocampus appear to be mainly involved in depressive disorders. Conclusions: Altered Wnt signalling may play a role in the pathophysiology of mood disorders, although not a central one. It is premature to draw conclusions regarding the possible usefulness of Wnt manipulations in the treatment of mood disorders.

Intramuscular Aripiprazole in the Acute Management of Psychomotor Agitation

To assess acute efficacy and safety of 9.75 mg of intramuscular (IM) injections of the atypical antipsychiatric aripiprazole in patients with schizophrenia or bipolar disorder and acute agitation.

Effectiveness of Short-Term Olanzapine in Patients With Bipolar-I Disorder, With or Without Comorbidity With Substance Use Disorder

Objectives Prognosis of comorbid bipolar disorder (BD) and drug abuse is poor. We assessed the efficacy of olanzapine in manic or mixed BD patients, with (SUD) or without (N-SUD) comorbidity with substance use disorder (SUD) and its effect on drug abuse, days of abuse, and craving. Methods Eighty patients with BD-I (40 SUD) were hospitalized for a manic or mixed episode and received add-on olanzapine. Assessments were conducted at admission, discharge, and 4 and 8 weeks after discharge. Primary outcome was the proportion of responders and remitters in each group. We used a logistic regression model to adjust for possible confounders. We assessed craving and drug-abuse days with a visual analog scale and the Timeline Follow-Back. Results SUD and N-SUD were similar on response and remission, adjusted for sex, age, years ill, age at first episode, first episode depressive, number of hospitalizations, and duration of hospitalization (odds ratio, 1.09; 95% confidence interval, 1.02–2.29). Mood rating scores dropped significantly from baseline to end point in both groups. Timeline follow-back decreased in SUD from 22.5 to 7.3 at 8 weeks postdischarge, whereas craving dropped from 8.3 to 5.1 (P < 0.03). Conclusions The effectiveness of short-term olanzapine in BD-I mania or mixed mania did not differ according to SUD comorbidity. Treatment was followed by less substance use/abuse and craving in comorbid bipolar-SUD patients.

Neurobiological Evidence for the Primacy of Mania Hypothesis

Background: Athanasios Koukopoulos proposed the primacy of mania hypothesis (PoM) in a 2006 book chapter and later, in two peer-reviewed papers with Nassir Ghaemi and other collaborators. This hypothesis supports that in bipolar disorder, mania leads to depression, while depression does not lead to mania. Objective: To identify evidence in literature that supports or falsifies this hypothesis. Method: We searched the medical literature (PubMed, Embase, PsycINFO, and the Cochrane Library) for peer-reviewed papers on the primacy of mania, the default mode function of the brain in normal people and in bipolar disorder patients, and on illusion superiority until 6 June, 2016. Papers resulting from searches were considered for appropriateness to our objective. We adopted the PRISMA method for our review. The search for consistency with PoM was filtered through the neurobiological results of superiority illusion studies. Results: Out of a grand total of 139 records, 59 were included in our analysis. Of these, 36 were of uncertain value as to the primacy of mania hypothesis, 22 favoured it, and 1 was contrary, but the latter pooled patients in their manic and depressive phases, so to invalidate possible conclusions about its consistency with regard to PoM. All considered studies were not focused on PoM or superiority illusion, hence most of their results were, as expected, unrelated to the circuitry involved in superiority illusion. A considerable amount of evidence is consistent with the hypothesis, although indirectly so. Limitations. Only few studies compared manic with depressive phases, with the majority including patients in euthymia. Conclusion: It is possible that humans have a natural tendency for elation/optimism and positive self-consideration, that are more akin to mania; the depressive state could be a consequence of frustrated or unsustainable mania. This would be consistent with PoM.

Hiccup with aripiprazole plus benzodiazepines resolving with pregabalin and/or benzodiazepine switch/discontinuation: four case reports.

To the Editors: H iccup lasting for more than 2 days is termed protracted and hiccup lasting for more than 2 months is termed intractable; hiccup is associated with high mortality. The neurochemistry associated with hiccup is unknown. However, it is believed that dopamine facilitates the hiccup, whereas γ-aminobutyric acid (GABA) reduces it through GABAB receptors but may increase it through GABAA receptors. 2 In fact, antiparkinsonian medication induces it, whereas dopamine receptor blockers and the GABAB agonist baclofen are used in its treatment. Alternative proposed treatments include the dihydropyridine L-type calcium channel blocker, nimodipine, and the α2δ subunit of voltage-gated calcium channels ligands gabapentin and pregabalin. Gabapentin and pregabalin are active on L-, N-, P-, and R-type calcium channels. Summarizing the previous data, D2 dopamine and GABAA receptor facilitation activates the hiccup reflex in combination with voltage-gated calcium ions, whereas GABAB receptor activation, dopamine D2 inhibition, and voltage-gated calcium channel blockade inhibit the reflex. Calcium ion channel inhibition is able to block hiccup; however, the mechanism is currently unknown. Interestingly, dopaminergic firing of ventral tegmental area dopamine neurons is supported by N-type channels, and both Nand P-type channel–mediated calcium ion influx facilitate somatodendritic and terminal dopamine release. In addition, GABAB receptors directly inhibit voltage-gated calcium ion channels, whereas GABAA receptor activation increases intracytosol calcium in astrocytes

Does the efficacy of asenapine in bipolar disorder increase in the presence of comorbidity with a substance use disorder? A naturalistic study

Background: Asenapine is a second-generation antipsychotic approved in Europe for treating moderate-to-severe manic episodes in adults affected by type I bipolar disorder (BD-I). We aimed to compare its efficacy in psychiatric inpatients with BD-I, with or without substance use disorder (SUD). Methods: We administered flexible asenapine doses ranging from 5–20 mg/day to 119 voluntarily hospitalized patients with Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision (DSM-IV-TR) BD-I diagnosis, with or without SUD. Patients were assessed with clinician-rated questionnaires [i.e. Brief Psychiatric Rating Scale (BPRS), Young Mania Rating Scale (YMRS), Hamilton Depression Rating Scale (HDRS), Hamilton Anxiety Rating Scale (HARS), and Global Assessment of Functioning (GAF)]. Assessments were carried out at baseline (T0, prior to treatment), and 3 (T1), 7 (T2), 15 (T3), and 30 days (T4) after starting treatment for all clinical scales and at T0 and T4 for the GAF. Results: Patients improved on all scales (p < 0.001) across all timepoints, as shown both by paired-sample comparisons and by applying a repeated-measures, generalized linear model (GLM). Patients without comorbid SUD showed greater reductions in BPRS scores at T2 and T3, greater reduction in YMRS scores at T3, and lower HARS scores at all timepoints. HDRS scores did not differ between the two groups at any timepoint. However, the reduction in HARS scores in the comorbid group was stronger than in the BD-I only group, albeit not significantly. Side effects were few and mild-to-moderate. Conclusions: The open-label design and the relatively short observation period may expose to both type I and type II statistical errors (false positive and false negatives). Asenapine showed effectiveness and safety in hospitalized BD-I patients. Its effect was stronger in patients without comorbid SUD.

[Functional neuroimaging of the amygdala: the response to threatening and phobogenic stimuli].

Recent functional neuroimaging studies show that the amygdala has a central role in threat evaluation, in response to conditioned and unconditioned stimuli, in fear learning and fear extinction. The amygdala is involved in the pathophysiology of phobias and anxiety. In this review we critically examine the main findings of functional neuroimaging studies reporting data on the amygdala. Findings suggest that the response of the amygdala to threatening stimuli is mainly modulated by the infralimbic and prefrontal cortices, which inhibit activation of the amygdala (top-down inhibition), and by the hippocampus, the function of which is related to stimulus learning. The activity of the amygdala is modulated by various factors, like stimulus type and origin, emotion triggered by stimulus perception, and attention. The neural network comprising the amygdala and the frontal cortex is involved not only in top-down inhibition, but also in the emotional perception of facial expressions. This network also includes the thalamic pulvinar, which is densely interconnected with the amygdala, directly or indirectly, and which is activated by emotional face recognition of scary fear. Both top-down inhibition mechanisms and emotional face recognition are altered in anxiety disorders, particularly in specific and social phobia, resulting in reduced amygdalar activity inhibition after anxiety - or fear - inducing stimulus perception. Future functional neuroimaging studies will be able to provide new insights of normal and altered neurophysiology of the amygdala.

Increased serum Dickkopf-1 levels in drug-abusing psychotic patients.

BACKGROUND Dickkopf-1 (DKK1) is an inhibitor of the canonical Wnt pathway, which is known to be impaired in both psychotic and neurodegenerative disorders. Here, we examined serum DKK1 levels as an indicator of ongoing neurodegeneration in psychotic patients, with or without a recent or current history of drug abuse. METHODS We measured serum DKK1 levels by ELISA in 22 inpatients with psychosis and no history of drug abuse, 22 with psychosis and drug abuse, and 16 controls. We rated psychopathology using the following rating scales: the Positive and Negative Syndrome Scale (PANSS); the Clinical Global Impressions (CGI) severity scale; and the Global Assessment of Functioning (GAF) scale. Extrapyramidal motor symptoms were assessed by the Simpson-Angus Neurological Rating Scale (NRS). RESULTS Inpatients with psychosis and comorbid substance abuse showed significantly higher serum DKK1 levels than inpatients with psychosis and no comorbid substance abuse or controls. Comorbid patients had earlier onset, longer duration of psychosis, and more severe extrapyramidal motor symptoms. However, we did not find any significant correlation between DKK1 levels and rating scale scores. CONCLUSION Psychosis led to elevated serum DKK1 levels, and substance abuse led to a further increase. Knowing that there is a correlation between brain and blood levels of DKK1, we speculate that the observed increase in DKK1 levels reflects drug-induced neurotoxicity in our patients.