The efficacy of zuranolone in postpartum depression and major depressive disorder: a review & number needed to treat (NNT) analysis

INTRODUCTION

Major depressive disorder (MDD) is a common and debilitating mental illness. Postpartum depression (PPD) impacts women globally and is one of the most common complications of childbirth that is underdiagnosed and undertreated, adversely impacting the mental health of women, children, and partners.Available antidepressant medications require weeks to months before showing effect. In this setting, zuranolone, an oral neuroactive steroid and a positive allosteric modulator of GABAA receptors, is an attractive alternative as a rapid-acting antidepressant treatment.

AREAS COVERED

This article reviews zuranolone (SAGE217), focusing on available clinical studies in individuals with PPD and MDD. This paper adds to the extant literature by presenting the efficacy data as Number Needed to Treat (NNT) to facilitate indirect comparisons with other antidepressants.

EXPERT OPINION

Zuranolone is a novel rapid-acting (i.e. two week course) oral antidepressant for the treatment of adults with PPD with ongoing clinical trials evaluating its efficacy in adults with MDD. Zuranolone is well tolerated with no significant safety concerns in any clinical trials completed to date. Zuranolone will be scheduled by the Drug Enforcement Agency (DEA).

Evaluating the neural substrates of effort-expenditure for reward in adults with major depressive disorder and obesity

Converging evidence has suggested that disturbances in monetary reward processing may subserve the shared biosignature between major depressive disorder (MDD) and obesity. However, there remains a paucity of studies that have evaluated the deficits in specific subcomponents of reward functioning in populations with MDD and obesity comorbidity. We evaluated the association between effort-expenditure for monetary reward and neural activation in regions associated with reward-based decision making (i.e., the caudate nucleus, anterior cingulate cortex (ACC) and hippocampus) in people with MDD and obesity comorbidity. We acquired structural and functional magnetic resonance imaging (fMRI) in 12 participants and performed a spherical region-of-interest analysis (ROI) using previously defined peak MNI coordinates. A one-sample t-test was employed to compare ROI-specific blood-oxygen-level-dependent (BOLD) signal change during the task choice selection window (i.e., high-effort vs. low-effort task) of the effort-expenditure for reward task (EEfRT). We observed no change in activation of the caudate nucleus, ACC or hippocampus in participants with increased BMI when contrasting the high effort > low effort reward magnitude condition for the EEfRT. The findings from our exploratory study evaluated the disturbances in fundamental reward processes, including cost-benefit decision making, in people MDD and obesity. Future studies should further investigate this relationship with a larger sample size.

The Effects of Psilocybin in Adults with Major Depressive Disorder and the General Population: Findings from Neuroimaging Studies

The use of psilocybin as treatment for major depressive disorder (MDD) has been examined as a promising alternative to traditional first-line options. We reviewed existing literature to provide a synthesis of the extant neuroimaging observations with psilocybin, and to identify putative therapeutic targets for target engagement studies with psilocybin, and potentially other psychedelics. We assessed neuroimaging observations with psilocybin among participants with MDD and healthy populations. A systematic search was conducted on PubMed, Google Scholar and PsycINFO from database inception to November 17th, 2021. The study quality (i.e., risk of bias) was assessed using the revised Cochrane risk-of-bias tool for randomized trials. A total of ten studies evaluated psilocybin in healthy populations and three studies assessed psilocybin in MDD participants using neuroimaging techniques. Following psilocybin administration, a decrease in amygdala activity and a reduction in depressive symptoms was observed in two studies. Changes in functional connectivity and activation of prefrontal limbic structures, specifically the ventral medial prefrontal cortex and amygdala, was seen in healthy populations. There was high heterogeneity in methodology (e.g., dosing schedule and imaging methods) amongst included studies. Longitudinal studies are needed to further elucidate psilocybin treatment for MDD, its long-term effects and the possibility of sustained therapeutic effects.

The effects of antidepressant medications on antiretroviral treatment adherence in HIV-positive individuals with depression

Background Extant literature has identified Major Depressive Disorder (MDD) as a comorbid disorder in individuals with seropositive human immunodeficiency disorder (HIV), and this may affect HIV-treatment efficacy. However, there is a paucity of literature evaluating the effects of antidepressant use on antiretroviral therapies (ART) in HIV-positive individuals. Herein, the following review assesses the effects of antidepressant medications on ART adherence in HIV-positive individuals with diagnosed MDD. Methods A systematic search on PubMed, Scopus, Web of Science, and Google Scholar search engines were conducted between database inception to June 12th, 2020 using the search and MeSH terms: (HIV) AND (antiretroviral or treatment) AND (depress*) AND (antidepressants) AND (adherence). Results We identified nine articles that evaluated ART adherence in HIV-positive individuals using antidepressants. Of the nine included articles, eight articles evaluated participants undergoing ART, and one article evaluated participants undergoing highly active antiretroviral therapy (HAART). Our primary findings suggest that patients who took antidepressant treatment for depression demonstrated greater adherence to HIV treatments and a reduction in missed HIV medication dosage. Limitations The heterogeneity of study design between the included studies was high. Conclusion The current review suggests that response to antidepressant medication may improve adherence to HIV treatments in HIV-positive individuals with comorbid depression. Further studies should expand the findings to explore the effects of disparate psychotropic agents on adherence behaviors among patients with HIV to identify the benefits of these agents on long-term health outcomes in this vulnerable clinical population.

Efficacy of ketamine and esketamine on functional outcomes in treatment-resistant depression: A systematic review

BACKGROUND

In recent years, ketamine and esketamine treatment have demonstrated rapid antidepressant effects in adults with treatment-resistant depression (TRD). Hitherto, relatively few studies have reported the effect of ketamine/esketamine treatment on functional outcomes (e.g., psychosocial functioning, workplace functioning). Herein, we review and synthesize extant literature reporting functional outcomes with ketamine/esketamine treatment in adults with TRD.

METHODS

A systematic review of clinical studies reporting subjective or objective ratings of general functioning as primary or secondary outcomes was performed.

RESULTS

Four randomized-controlled trials, one open-label clinical study and one case series reported on the efficacy of ketamine/esketamine on subjective measures of general functioning. Overall, mixed results were reported with respect to the effect across disparate functional measures (e.g., Sheehan Disability Scale [SDS]) using ketamine/esketamine. A single study demonstrated a significant decrease (i.e., improvement) in SDS total scores in TRD with esketamine treatment; most studies, however, did not report on functional outcomes and have functional outcomes as a (co)-primary outcome measure.

LIMITATIONS

Clinical studies that were included evaluated work- or social-related disability as a secondary outcome using subjective rating scales.

CONCLUSION

Functional outcomes in adults with TRD receiving ketamine/esketamine was insufficiently characterized. Available evidence indicates that improvements in general psychosocial functioning is apparent. The association, if any, between symptomatic improvement and functional improvement in TRD, as well as the temporality to improve functioning, are future research vistas.

Safety, Tolerability, and Real-World Effectiveness of Intravenous Ketamine in Older Adults With Treatment-Resistant Depression: A Case Series

OBJECTIVE

To evaluate the safety, tolerability, and effectiveness of repeated doses of intravenous (IV) ketamine in older adults (i.e., ≥60 years of age) with treatment-resistant depression.

METHOD

In this case series, fifty-three older adults (M_age = 67, SD = 6; 57% female [n = 30]) received 4 IV ketamine infusions, administered over 1-2 weeks. Effectiveness of IV ketamine was measured using the Quick Inventory for Depressive Symptomatology-Self Report 16 (QIDS-SR16) approximately 2 days after infusions 1-3, and 1-2 weeks after infusion 4. Safety was measured as hemodynamic changes before, during, immediately after, and 20 minutes after each infusion. Tolerability was assessed via systematic reporting of treatment-emergent adverse events during and after each infusion, in addition to symptoms of dissociation measured using the Clinician Administered Dissociative States Scale. Partial response (25%-50% symptomatic improvement from baseline), response (≥50% symptomatic improvement from baseline), clinically significant improvements (≥25% symptomatic improvement from baseline), and remission rates (QIDS-SR16 ≤5) were also calculated.

RESULTS

Participants reported significant decreases in depressive symptoms (i.e., as measured by the QIDS-SR16) with repeated ketamine infusions (F(4, 92) = 7.412, p <0.001). The mean QIDS-SR16 score was 17.12 (SD = 5.33) at baseline and decreased to 12.52 (SD = 5.79) following 4 infusions. After 4 infusions, 31% (n = 8) of participants partially responded to IV ketamine, 27% (n = 7) responded, 58% (n = 15) experienced clinically significant improvements, and 10% (n = 3) met remission criteria. Thirty-six participants (69%) experienced treatment-emergent hypertension during at least 1 infusion, and 10 (19%) required intervention with an antihypertensive. Drowsiness was the most commonly reported adverse event (50% of infusions; n = 73).

CONCLUSION

Ketamine was associated with transient treatment-emergent hypertension. Response and remission rates were comparable to those reported in general adult samples. Findings are limited by the open-label, chart review nature of this study.

Does pre-treatment functioning influence response to intravenous ketamine in adults with treatment-resistant depression?

BACKGROUND

The efficacy of monoamine-based antidepressants in adults with major depressive disorder (MDD) is attenuated in persons with greater pre-treatment functional impairment. Herein, we investigated whether pre-treatment functioning in outpatients with treatment-resistant depression (TRD) moderates response to intravenous (IV) ketamine.

METHODS

Adults (N= 326; M_age = 45) with DSM-5-defined MDD or bipolar disorder and TRD received repeat-dose IV ketamine at a community-based clinic. Function was evaluated with the Sheehan Disability Scale (SDS), using total scores as well as scores on the subdomains of workplace/school, social life, and family life/home responsibilities. The primary dependent measure was change in depressive symptoms from pre-treatment to post-infusion 4, as measured by the Quick Inventory for Depressive Symptomatology-Self Report-16.

RESULTS

Total functional disability, as well as the subdomains of social life and family life/home responsibilities, significantly moderated response to IV ketamine (p = .003; p = .008; p = .008). Follow-up simple slopes analyses indicated a significant improvement in depressive symptoms across the functional domain spectrum (ps < .001). Above average functional disability (i.e., 1 SD > mean functional impairment within the sample) was associated with a greater change in depressive symptoms. Workplace function did not significantly moderate response to IV ketamine (p = .307), suggesting that individuals with significantly impaired workplace functioning may expect a similar response to ketamine as those with less workplace impairment.

CONCLUSIONS

Symptomatic benefit with IV ketamine was observed in patients with TRD and significant pre-treatment functional impairment. The foregoing result has implications for mechanism of action, cost-effectiveness, and patient selection in adults with TRD receiving IV ketamine.

Do sleep changes mediate the anti-depressive and anti-suicidal response of intravenous ketamine in treatment-resistant depression?

Sleep disturbances are commonly reported in patients with treatment-resistant depression (TRD). Available data have shown that intravenous (IV) ketamine is an effective treatment for patients with TRD and growing data suggest ketamine may improve overall sleep architecture. In the present study, we evaluated whether changes in sleep symptoms mediated the anti-depressive and/or anti-suicidal effects of IV ketamine and whether improvement in sleep correlated with a higher likelihood of achieving response or remission. Adults with TRD received four infusions of IV ketamine at a community-based clinic. Total depressive symptom severity was measured with the Quick Inventory Depressive Symptoms Self-Report 16-Item (QIDS-SR₁₆ ) at baseline and was repeated across four infusions. Suicidal ideation (SI) and four sleep symptoms were measured using the SI item and the five sleep items on the QIDS-SR₁₆ . A total of 323 patients with TRD received IV ketamine. Self-reported improvements in insomnia, night-time restlessness, hypersomnia, early morning waking, and total sleep were significant partial mediators to the improvements observed in depression severity. Similarly, insomnia, night-time restlessness, early morning waking and total sleep improvements mediated the reduction of IV ketamine on SI. All sleep items, except for hypersomnia, were associated with an increased likelihood of achieving response or remission. Notably, each point improvement in total sleep score was significantly associated with achieving responder/remitter status (odds ratio 3.29, 95% confidence interval 2.00-5.41). Insomnia, sleep restlessness, early morning waking and total sleep improvements were significant mediators of antidepressant and anti-suicidal improvements in patients with TRD receiving IV ketamine.

Strategies to Prolong Ketamine's Efficacy in Adults with Treatment-Resistant Depression

INTRODUCTION

Ketamine treatment is capable of significant and rapid symptom improvement in adults with treatment-resistant depression (TRD). A limitation of ketamine treatment in TRD is the relatively short duration of time to relapse (e.g., median 2-4 weeks). The objective of the systematic review herein is to identify strategies capable of prolonging the acute efficacy of ketamine in adults with TRD.

METHODS

PubMed/MEDLINE databases were searched from inception to December 2020 for clinical studies written in English using the following key terms: ketamine, prolong, and depression. A total of 454 articles were identified from the literature search which included all clinical studies regarding prolonging the antidepressant effects of ketamine. Twenty-two articles were included: ten randomized controlled trials (RCTs), eight prospective open-label trials, one retrospective chart review, and three case reports. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used for data extraction. The primary outcome was prolonged effect, defined as statistically significant antidepressant effects following acute ketamine treatment.

RESULTS

A total of 454 articles were identified, and 22 articles were included. Different treatment modalites including pharmacological interventions, manualized-based psychotherapies, electroconvulsive therapy, transcranial magnetic stimulation, and intravenous monotherapy were examined to determine their impact on the prolongation of antidepressant effects following acute ketamine treatment. No treatment modality, other than repeat-dose IV ketamine, has demonstrated ability to significantly prolong the acute efficacy of IV ketamine in TRD.

CONCLUSION

Hitherto, available open-label data and controlled trial data support repeat administration of IV ketamine as an effective strategy to prolong the efficacy of ketamine's antidepressant effects (although not the focus of the study herein, maintenance repeat-dose esketamine treatment is proven effective in esketamine responders). There is a need to identify multimodality strategies that are safe and capable of prolonging the efficacy of ketamine in adults with TRD.

The impact of overweight/obesity on monetary reward processing: A systematic review

OBJECTIVE

Converging evidence suggests abnormalities in monetary reward processing may underlie the shared pathophysiology between major depressive disorder and obesity. As such, there is a need to parse deficits in specific subcomponents of monetary reward functioning (i.e., valuation, learning and anticipation).

METHODS

PsycINFO, Google Scholar and PubMed databases were searched for English-language articles published between database inception to June 6th, 2020. Studies were identified using the following medical search heading (MeSH) terms and search strings: (reward (valuation OR motivation OR anticipation OR learning OR functioning OR decision-making OR reinforcement)) AND ((obesity OR overweight OR obese).

RESULTS

Findings were reviewed from 11 studies evaluating the association between obesity and monetary reward processing. Four studies found significant differences in reward learning in individuals with obesity compared to normal-weight participants. Five studies found body mass index (BMI) to be predictive of willingness to expend effort (i.e., valuation) for a monetary reward. Three studies found changes in neural activations in the ventral striatum during anticipatory phases preceding receipt of a monetary reward in participants with obesity.

CONCLUSIONS

Participants with obesity demonstrated significantly poorer performance in task-based measures of reward learning, valuation, and anticipation, resulting in lower monetary reward outcomes across all studies compared to healthy controls. Notably, participants with obesity and comorbid depression performed worse than participants with no comorbid depression.

LIMITATIONS

There persists heterogeneity between studies with regards to inclusion of mood disorder populations and exclusion of psychiatric comorbidities in groups with obesity.

Ketamine-induced urological toxicity: potential mechanisms and translation for adults with mood disorders receiving ketamine treatment

Intravenous (IV) ketamine has been shown to have rapid and robust antidepressant effects in adults with treatment-resistant depression (TRD). Urological toxicity has been observed in chronic ketamine abusers as evidenced by dysuria, urgency, and hematuria. The foregoing observation provides the basis for evaluating whether ketamine-induced urological toxicity (KIUT) is associated with sub-anesthetic doses of ketamine (0.5-1.0 mg/kg) in adults with mood disorders. The overarching objective of this article is to identify potential mechanisms of KIUT which appears to be dose and frequency dependent. Available research indicates that high-frequency ketamine is associated with disruption of the urothelial barrier as well as direct ketamine toxicity (i.e., decreased expression of junction proteins) in KIUT of the bladder. Chronic and high-frequency ketamine use is also associated with bladder inflammation mediated via neurogenic and IgE inflammation. Other non-mutually exclusive causes are nerve hyperplasia, hypersensitivity, cell apoptosis, microvascular damage, and overexpression of carcinogenic genes. Notwithstanding the evidence of KIUT in ketamine abusers, there is no evidence that ketamine and/or esketamine treatment in adults with mood disorders is associated with KIUT. However, all patients receiving ketamine/esketamine for mood disorder treatment should be queried about genitourinary symptoms during acute and, where applicable, maintenance dosing.

Early symptomatic improvements as a predictor of response to repeated-dose intravenous ketamine: Results from the Canadian Rapid Treatment Center of Excellence

BACKGROUND

Early symptomatic improvement with monoamine-based antidepressants is predictive of treatment response. The objective of this study was to determine if early symptomatic improvements with intravenous (IV) ketamine predicted treatment response to an acute course of four infusions.

METHOD

134 adults with treatment resistant depression (TRD) received four ketamine infusions over one to two weeks. Depressive symptoms were measured using the Quick Inventory for Depressive Symptomatology Self-Report₁₆ (QIDS-SR₁₆) at baseline and post-infusions 1, 2, 3, and 4. Early improvement was defined as ≥20% reduction in QIDS-SR₁₆ scores after the first or second infusion. Linear models were used to determine whether early improvement was associated with post-infusion 4 QIDS-SR₁₆ scores after controlling for baseline characteristics.

RESULTS

Early improvement post-infusion 1 (β = -3.52, 95% BCa CI [-5.40, -1.78]) and 2 (β = -3.16, 95% BCa CI [-5.75, -1.59]) both significantly predicted QIDS-SR₁₆ scores post-infusion 4. Early improvers had significantly lower QIDS-SR₁₆ scores at post-infusion 4 (post-infusion 1 improvers: M = 9.8, SD = 4.5; post-infusion 2 improvers: M = 10.6, SD = 5.7) compared to non-early improvers (post-infusion 1 non-improvers: M = 13.7, SD = 5.8; post-infusion 2 non-improvers: M = 14.1, SD = 5.3) when controlling for baseline characteristics. The majority (58%) of individuals who did not improve post-infusions 1 or 2 still experienced an antidepressant response or partial response (≥20% reduction in QIDS-SR₁₆) post-infusion 4.

LIMITATIONS

This is a post-hoc analysis of an open-label study.

CONCLUSION

Early improvement was associated with greater antidepressant effects following a course of four ketamine infusions. However, individuals who did not show early improvements still had a high likelihood of experiencing clinically significant symptom reduction after the fourth infusion, suggesting that completing four infusions, regardless of early symptom changes, is appropriate and merited.

A simplified 6-Item clinician administered dissociative symptom scale (CADSS-6) for monitoring dissociative effects of sub-anesthetic ketamine infusions

BACKGROUND

Dissociation is a treatment-emergent adverse event commonly associated with IV ketamine, often measured using the 23-item Clinician-Administered Dissociative States Scale (CADSS). The objective of this study was to develop a short form version of the CADSS for easier clinical use.

METHODS

Retrospective data of 260 patients with treatment-resistant depression (TRD) receiving IV ketamine were randomly divided into two datasets. The first dataset (n = 130) was leveraged to develop a brief 6-item version of the CADSS (CADSS-6) based on items most sensitive to ketamine-induced dissociation. The CADSS-6 questions were then applied to the second dataset (n = 130) and the Spearman's correlation between the full-length CADSS and the CADSS-6 were assessed.

RESULTS

The CADSS-6 was developed from questions 1, 2, 6, 7, 15, and 22 from the full length CADSS. There was a strong significant correlation between the CADSS-6 total score and the CADSS total score at infusions 1 (rs(106) = 0.92, p < 0.001), 2 (rs(100) = 0.91, p < 0.001), 3(rs(99) = 0.95, p < 0.001) and 4 (rs(102) = 0.94, p < 0.001).

LIMITATIONS

The CADSS-6 was developed using a retrospective data; therefore, the scale remains unvalidated in this population.

CONCLUSIONS

The CADSS-6 presented herein was sensitive to dissociation experienced by patients receiving IV ketamine. Overall, the CADSS-6 was strongly correlated at each infusion with the full-length CADSS. While future studies should look to validate the CADSS-6 in a TRD sample, this scale offers clinicians a brief assessment that can be used to characterize symptoms of dissociation.

Management of cognitive impairment in bipolar disorder: a systematic review of randomized controlled trials

Cognitive impairment is common in bipolar disorder and is emerging as a therapeutic target to enhance quality of life and function. A systematic search was conducted on PubMed, PsycInfo, Cochrane, clinicaltrials.gov, and Embase databases for blinded or open-label randomized controlled trials evaluating the pro-cognitive effects of pharmacological, neurostimulation, or psychological interventions for bipolar disorder. Twenty-two trials were identified, evaluating a total of 16 different pro-cognitive interventions. The methodological quality of the identified trials were assessed using the Cochrane Risk of Bias tool. Currently, no intervention (i.e., pharmacologic, neurostimulation, cognitive remediation) has demonstrated robust and independent pro-cognitive effects in adults with bipolar disorder. Findings are preliminary and methodological limitations limit the interpretation of results. Methodological considerations including, but not limited to, the enrichment with populations with pre-treatment cognitive impairment, as well as the inclusion of individuals who are in remission are encouraged. Future trials may also consider targeting interventions to specific cognitive subgroups and the use of biomarkers of cognitive function.

The effectiveness of ketamine on anxiety, irritability, and agitation: Implications for treating mixed features in adults with major depressive or bipolar disorder

OBJECTIVE

To determine the effectiveness of intravenous (IV) ketamine on anxiety, irritability, agitation, and suicidality, in adults with treatment-resistant major depressive disorder (MDD) or bipolar disorder (BD).

METHOD

Adults (N = 201) with treatment-resistant MDD or BD received repeat-dose IV ketamine treatment at a community-based clinic. Mixed features were measured using symptoms of anxiety, irritability, and agitation (AIA), as measured by the Generalized Anxiety Disorder-7 (GAD-7) scale. The Quick Inventory for Depressive Symptomatology Self-Report-16 (QIDS-SR₁₆ ) was used to measure overall treatment response, and the QIDS-SR₁₆ suicidal ideation (SI) item was used to measure change in SI symptoms with ketamine treatment. The anxiety, irritability, and agitation items on the GAD-7 were used to assess effectiveness of IV ketamine in treating symptoms of mixed features.

RESULTS

In this retrospective analysis, 113 participants met AIA criteria. Participants with AIA experienced a significantly greater reduction in overall depressive symptoms (F(1, 558) = 9.49, P = .002), SI (F(1, 558) = 3.103, P = .079), anxiety (F(1, 198) = 5.52, P = .007), irritability (F(1, 198) = 28.35, P < .001), and agitation as measured by "trouble relaxing" (F(1, 198) = 6.70, P = .010) from baseline compared to the non-AIA group, regardless of number of treatments received.

CONCLUSIONS

Our preliminary results suggest that IV ketamine is effective in rapidly treating AIA and SI in adults with treatment-resistant mood disorders. This observation suggests that IV ketamine could be considered a treatment alternative for adults with MDD or BD presenting with mixed features.

Safety and tolerability of IV ketamine in adults with major depressive or bipolar disorder: results from the Canadian rapid treatment center of excellence

OBJECTIVES

Rigorous clinical trials suggest ketamine is safe and well-tolerated in patients with treatment-resistant depression (TRD). There is a paucity of data on the safety and tolerability of ketamine in community-based clinics treating patients with TRD.

METHODS

Retrospective data was analyzed from 203 patients with TRD who received repeat-dose IV ketamine. Safety was operationalized as hemodynamic changes. Tolerability was evaluated through the reporting of adverse events and dissociation symptom severity, as measured by the Clinician-Administered Dissociative States Scale.

RESULTS

Ketamine was well-tolerated, with less than 5% of patients withdrawing due to tolerability concerns. Blood pressure significantly increased during infusion, with 44.3% meeting criteria for treatment-emergent hypertension (i.e., blood pressure ≥ 165/100 mmHg). 12% of patients exhibiting hypertension required pharmacological intervention. The most frequently reported adverse events included drowsiness (56.4%), dizziness (45.2%), dissociation (35.6%), and nausea (13.3%). Dissociation severity significantly attenuated after the first infusion, but plateaued for subsequent infusions.

CONCLUSION

Intravenous ketamine was safe and well-tolerated. Hypertension was commonly observed and was often transient. Dissociation was most frequently reported after the first infusion but remained a consistent but not treatment-limiting adverse event thereafter. No patients exhibited psychosis, mania, or new onset suicidality with IV ketamine.

Parsing metabolic heterogeneity in mood disorders: A hypothesis-driven cluster analysis of glucose and insulin abnormalities

OBJECTIVES

Metabolically based distinctions for disturbances in glucose and insulin may provide meaningful insights both clinically and mechanistically.

METHODS

Data were derived from 352 subjects of previously completed clinical studies with a mood disorder (MD) (bipolar disorder: n = 179, major depressive disorder: n = 173) and 218 healthy controls from the Comprehensive Assessment of Long-Term Effects of Reducing Intake of Energy. We conducted a factor analysis to replicate a priori dissociable factors informed by glucose and insulin levels and indices of insulin resistance and beta-cell function: elevated insulin and insulin resistance ("insulin-IR"), and increased fasting glucose and reduced insulin secretion ("glucotoxicity"). Cluster analyses were conducted, separately in men and women, to evaluate the clinical relevance of subtyping individuals with MDs using insulin-IR and glucotoxicity (GT) factor scores.

RESULTS

Factors insulin-IR and GT explained 92.64% and 92.09% of the variance in men and women respectively. Three clusters were replicated in men and women separately: metabolically healthy (MH), high GT, and insulin-resistant (IR). After adjusting for age, gender, study cohort, MD diagnosis, and antipsychotics use, body mass index (BMI) and mean arterial pressure were higher in IR- vs GT- or MH-clustered individuals; GT-clustered individuals had more metabolic syndrome components and higher C-reactive protein. Glucotoxic-clustered subjects reported greater impairments in cognitive function and global functioning when compared to MH- or IR-clustered subjects.

CONCLUSIONS

Using simple, cost-effective, and accessible measures, we identified stable, gender-convergent, subgroups of individuals that significantly diverged on measures of cognitive dysfunction, self-reported anhedonia, functional disability, BMI, and blood pressure.

Machine learning and big data: Implications for disease modeling and therapeutic discovery in psychiatry

INTRODUCTION

Machine learning capability holds promise to inform disease models, the discovery and development of novel disease modifying therapeutics and prevention strategies in psychiatry. Herein, we provide an introduction on how machine learning/Artificial Intelligence (AI) may instantiate such capabilities, as well as provide rationale for its application to psychiatry in both research and clinical ecosystems.

METHODS

Databases PubMed and PsycINFO were searched from 1966 to June 2016 for keywords:Big Data, Machine Learning, Precision Medicine, Artificial Intelligence, Mental Health, Mental Disease, Psychiatry, Data Mining, RDoC, and Research Domain Criteria. Articles selected for review were those that were determined to be aligned with the objective of this particular paper.

RESULTS

Results indicate that AI is a viable option to build useful predictors of outcome while offering objective and comparable accuracy metrics, a unique opportunity, particularly in mental health research. The approach has also consistently brought notable insight into disease models through processing the vast amount of already available multi-domain, semi-structured medical data. The opportunity for AI in psychiatry, in addition to disease-model refinement, is in characterizing those at risk, and it is likely also relevant to personalizing and discovering therapeutics.

CONCLUSIONS

Machine learning currently provides an opportunity to parse disease models in complex, multi-factorial disease states (e.g. mental disorders) and could possibly inform treatment selection with existing therapies and provide bases for domain-based therapeutic discovery.

Pharmacological Treatment of Cognitive Symptoms in Major Depressive Disorder

BACKGROUND

Cognitive dysfunction is a core transdiagnostic domain of Major Depressive Disorder (MDD) and is a principal determinant of functional recovery. However, it has been insufficiently targeted within the current therapeutic framework for MDD.

OBJECTIVE

To highlight these unmet cognitive needs in MDD.

METHOD

An article search was conducted using PubMed from inception to November 2016: Major Depressive Disorder (and/or variant) was cross-referenced with the following terms: antidepressants, augmentation, cognition, cognitive deficits, cognitive dysfunction, functional outcomes, mechanism of action, and treatment. Articles informed by observational studies, clinical trials, and review articles relevant to the discussion of cognition and cognitive impairment in MDD were included for review. Additional terms and citations previously not identified in the initial search were obtained from a manual review of article reference lists.

RESULTS

Cognitive deficits in MDD are replicable, non-specific, and clinically significant. Abnormalities in the domains of learning/memory, executive function, attention, concentration, and processing speed are consistently reported. Only two antidepressants (i.e., duloxetine and vortioxetine) have established procognitive effects utilizing rigorous methodology in MDD. Most antidepressants improve cognitive function(s), but the extent to which they directly exert pro-cognitive effects is not yet understood.

CONCLUSION

Cognitive dysfunction in MDD is a principal determinant of patient-reported outcomes (e.g., psychosocial function). Healthcare providers are encouraged to screen for cognitive dysfunction in MDD and familiarize themselves with the efficacy profiles of antidepressants on disparate cognitive domains.

Perceived sleep quality predicts cognitive function in adults with major depressive disorder independent of depression severity

BACKGROUND

The aim of this study was to examine the role of perceived sleep quality in predicting subjective as well as objective cognitive function in adults with major depressive disorder (MDD).

METHODS

Adults with recurrent MDD (n = 100) experiencing a major depressive episode of at least moderate severity and age-, sex-, and education-matched healthy controls (HC) (n = 100) were recruited to participate in a clinical trial validating the THINC-integrated tool (THINC-it; NCT02508493) for cognitive function. The THINC-it includes subjective and objective measures of cognitive function. Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI).

RESULTS

Compared with HC, individuals with MDD reported significantly poorer sleep quality, as assessed by domain and global PSQI scores (all P values <.05). Both perceived sleep quality (P < .001) and depression severity (P = .002) were found to independently predict impairments in subjective cognitive performance. Only perceived sleep quality predicted objective cognitive impairments (P = .017). Exploratory mediation analysis revealed depression severity to be a partial mediator of the relationship between perceived sleep quality and subjective cognitive performance (95% confidence interval [CI]: -0.56, -0.33).

CONCLUSIONS

The results indicate that the subjective and objective cognitive impairments are differentially related to perceived sleep quality and depression severity and emphasize the importance of treating sleep disturbances in MDD.

Cognitive impairment as measured by the THINC-integrated tool (THINC-it): The association with self-reported anxiety in Major Depressive Disorder

BACKGROUND AND OBJECTIVES

This study evaluated the association between self-reported anxiety and objective/subjective measures of cognitive performance in adults with Major Depressive Disorder (MDD).

METHODS

Acutely depressed subjects with recurrent MDD (n = 100) and age-, sex-, and education-matched healthy controls (HC; n = 100) between the ages of 18 and 65 completed the cross-sectional validation study of the THINC-integrated tool (THINC-it; ClinicalTrials.gov: NCT02508493). Objective cognitive performance was assessed using the THINC-it, and subjective cognitive impairment with the Perceived Deficits Questionnaire for Depression-5-item. Subjects also completed the Generalized Anxiety Disorder-7-item (GAD-7) questionnaire.

RESULTS

Subjects with MDD reported significantly more anxiety symptoms, as assessed by the GAD-7, compared to HC (p < 0.001). Linear regression analysis determined that anxiety symptoms significantly accounted for 70.4% of the variability in subjective cognitive impairment, adjusting for depression severity. Moreover, subjects' ratings of the difficulties caused by their anxiety were reported as significantly more severe among subjects with MDD when compared to HC (p < 0.001). Likewise, greater self-reported difficulties with anxiety significantly predicted 57.8% of the variability in subjective cognitive impairment, adjusting for depression severity. Neither anxiety symptoms nor impairment due to anxiety symptoms predicted objective cognitive performance.

LIMITATIONS

Subjects were not prospectively verified to have a clinical diagnosis of GAD. Rather, this study examined the relationships between symptoms of generalized anxiety, assessed using a brief screening tool, and subjective and objective cognitive function.

CONCLUSIONS

Results from the current study indicate that adults with MDD and high levels of self-reported anxiety are significantly more likely to report experiencing subjective cognitive dysfunction.

Stability, reliability, and validity of the THINC-it screening tool for cognitive impairment in depression: A psychometric exploration in healthy volunteers

OBJECTIVES

There is a need for a brief, reliable, valid, and sensitive assessment tool for screening cognitive deficits in patients with Major Depressive Disorders. This paper examines the psychometric characteristics of THINC-it, a cognitive assessment tool composed of four objective measures of cognition and a self-rated assessment, in subjects without mental disorders.

METHODS

N = 100 healthy controls with no current or past history of depression were tested on four sequential assessments to examine temporal stability, reliability, and convergent validity of the THINC-it tests. We examined temporal reliability across 1 week and stability via three consecutive assessments. Consistency of assessment by the study rater (intrarater reliability) was calculated using the data from the second and third of these consecutive assessments.

RESULTS

Test-retest reliability correlations varied between Pearson's r = 0.75 and 0.8. Intrarater reliability between 0.7 and 0.93. Stability for the primary measure for each test yielded within-subject standard deviation values between 5.9 and 11.23 for accuracy measures and 0.735 and 17.3 seconds for latency measures. Convergent validity for three tasks was in the acceptable range, but low for the Symbol Check task.

CONCLUSIONS

Analysis shows high levels of reliability and stability. Levels of convergent validity were modest but acceptable in the case of all but one test.

Predictors of Response to Ketamine in Treatment Resistant Major Depressive Disorder and Bipolar Disorder

Objectives: Extant evidence indicates that ketamine exerts rapid antidepressant effects in treatment-resistant depressive (TRD) symptoms as a part of major depressive disorder (MDD) and bipolar disorder (BD). The identification of depressed sub-populations that are more likely to benefit from ketamine treatment remains a priority. In keeping with this view, the present narrative review aims to identify the pretreatment predictors of response to ketamine in TRD as part of MDD and BD. Method: Electronic search engines PubMed/MEDLINE, ClinicalTrials.gov, and Scopus were searched for relevant articles from inception to January 2018. The search term ketamine was cross-referenced with the terms depression, major depressive disorder, bipolar disorder, predictors, and response and/or remission. Results: Multiple baseline pretreatment predictors of response were identified, including clinical (i.e., Body Mass Index (BMI), history of suicide, family history of alcohol use disorder), peripheral biochemistry (i.e., adiponectin levels, vitamin B12 levels), polysomnography (abnormalities in delta sleep ratio), neurochemistry (i.e., glutamine/glutamate ratio), neuroimaging (i.e., anterior cingulate cortex activity), genetic variation (i.e., Val66Met BDNF allele), and cognitive functioning (i.e., processing speed). High BMI and a positive family history of alcohol use disorder were the most replicated predictors. Conclusions: A pheno-biotype of depression more, or less likely, to benefit with ketamine treatment is far from complete. Notwithstanding, metabolic-inflammatory alterations are emerging as possible pretreatment response predictors of depressive symptom improvement, most notably being cognitive impairment. Sophisticated data-driven computational methods that are iterative and agnostic are more likely to provide actionable baseline pretreatment predictive information.

Is binge eating a cognitive disorder? Results from the International Mood Disorders Collaborative Project

BACKGROUND

Individuals with binge eating disorder (BED) are differentially affected by attention-deficit/hyperactivity disorder (ADHD), obesity, and substance use disorder. We have investigated to what extent cognitive deficits are relevant to binge eating behavior (BEB).

METHODS

Data from the International Mood Disorders Collaborative Project were retrospectively and cross-sectionally analyzed to compare individuals with and without BEB on measures of anhedonia and general cognitive functions (n = 566). BEB was assessed using items from the Mini International Neuropsychiatric Interview Plus 5.0.0 for DSM-IV-TR that correspond with DSM-5-defined diagnostic criteria for BED. Individuals currently prescribed benzodiazepines were excluded from analyses.

RESULTS

Individuals with BEB were more likely to exhibit anhedonia (P = .044) and general cognitive (P = .005) symptoms, when compared to those without BEB. We also observed that individuals with BEB were more likely to have specific psychiatric (eg, ADHD) and medical (eg, obesity) disorders (P < .05).

CONCLUSIONS

Our results suggest that a central disturbance in cognitive processes may be mechanistically relevant to the cause and treatment of BEB in adults.

Determinants of cognitive function in individuals with type 2 diabetes mellitus: A meta-analysis

BACKGROUND

Type 2 diabetes mellitus (T2DM) is associated with deficits across multiple cognitive domains; however, the determinants of cognitive impairment in T2DM are not well characterized. We aimed to evaluate body mass index (BMI), glycemic control, and T2DM duration as moderators of cognitive dysfunction in T2DM.

METHODS

We conducted a meta-analytic review of the literature reporting data on BMI, hemoglobin A1c (HbA1c), T2DM duration, and validated measures of processing speed (ie, Digit Symbol Substitution Test, Trail Making Test [TMT]-A), verbal learning and memory (ie, Rey Auditory Verbal Learning Test), and working memory/executive function (ie, TMT-B) among individuals with vs without T2DM.

RESULTS

Individuals with T2DM demonstrated deficits across multiple cognitive domains (k = 40; n = 4,252 T2DM; n = 22,322 non-T2DM; effect sizes 0.21 to 0.35). Illness duration and BMI did not significantly moderate measures of cognition; however, higher HbA1c levels were significantly associated with deficits in measures of processing speed (R2 values 0.41 to 0.73, P < .01) and working memory/executive function (R2 = 0.62, P < .001).

CONCLUSIONS

Adults with T2DM exhibited significant deficits across multiple domains of cognitive function. Additionally, we identified an association between poorer glycemic control and cognitive dysfunction. A clinical translation of our findings relates to the reduction in morbidity by improving glycemic control.

Brain structural networks and connectomes: the brain-obesity interface and its impact on mental health

PURPOSE

Obesity is a complex and multifactorial disease identified as a global epidemic. Convergent evidence indicates that obesity differentially influences patients with neuropsychiatric disorders providing a basis for hypothesizing that obesity alters brain structure and function associated with the brain's propensity toward disturbances in mood and cognition. Herein, we characterize alterations in brain structures and networks among obese subjects (ie, body mass index [BMI] ≥30 kg/m²) when compared with non-obese controls.

PATIENTS AND METHODS

We obtained noninvasive diffusion tensor imaging and generalized q-sampling imaging scans of 20 obese subjects (BMI=37.9±5.2 SD) and 30 non-obese controls (BMI=22.6±3.4 SD). Graph theoretical analysis and network-based statistical analysis were performed to assess structural and functional differences between groups. We additionally assessed for correlations between diffusion indices, BMI, and anxiety and depressive symptom severity (ie, Hospital Anxiety and Depression Scale total score).

RESULTS

The diffusion indices of the posterior limb of the internal capsule, corona radiata, and superior longitudinal fasciculus were significantly lower among obese subjects when compared with controls. Moreover, obese subjects were more likely to report anxiety and depressive symptoms. There were fewer structural network connections observed in obese subjects compared with non-obese controls. Topological measures of clustering coefficient (C), local efficiency (E_local), global efficiency (E_global), and transitivity were significantly lower among obese subjects. Similarly, three sub-networks were identified to have decreased structural connectivity among frontal-temporal regions in obese subjects compared with non-obese controls.

CONCLUSION

We extend knowledge further by delineating structural interconnectivity alterations within and across brain regions that are adversely affected in individuals who are obese.

Sex differences in the mediators of functional disability in Major Depressive Disorder

The aim of this study was to investigate sex differences in discrete domains of psychopathology as mediators of functional disability among individuals with Major Depressive Disorder (MDD). Adults (ages 18-65) with moderate-to-severe MDD (n = 100) and age-, sex-, and education-matched healthy controls (HC; n = 100) participated in a clinical trial validating the THINC-integrated tool, a newly developed cognitive assessment tool for patients with MDD. Variables assessed as possible mediators included depression symptom severity, anxiety symptoms, sleep disturbance, perceived cognitive deficits, and objective cognitive performance. Functional disability was assessed using the total score on the Sheehan Disability Scale. Separate mediation analyses were conducted for men and women. No significant differences were detected between men and women on the assessed domains of psychopathology or functional disability (ps > 0.05). However, the mediation analyses demonstrated different patterns with respect to determinants of functional disability in MDD between men and women. Functional disability was mediated by anxiety (95% CI: -3.17, -0.28) and sleep disturbance (95% CI: -0.69, -0.05) among men and by depressive symptom severity (95% CI: -7.82, -0.32) among women. These preliminary results instantiate the need to dimensionalize psychopathology in MDD. Our results at least in part support the hypothesis that, consistent with the sex differences in the prevalence and illness presentation of MDD, determinants of functional outcomes also differ between men and women, underscoring the need to consider sex differences in order to improve functional outcomes in the treatment of MDD.

Air pollution, aeroallergens and suicidality: a review of the effects of air pollution and aeroallergens on suicidal behavior and an exploration of possible mechanisms

OBJECTIVE

Risk factors for suicide can be broadly categorized as sociodemographic, clinical and treatment. There is interest in environmental risk and protection factors for suicide. Emerging evidence suggests a link between environmental factors in the form of air pollution and aeroallergens in relation to suicidality.

METHODS

Herein, we conducted a systematic review of 15 articles which have met inclusion criteria on the aforementioned effects.

RESULTS

The majority of the reviewed articles reported an increased suicide risk alongside increased air pollutants or aeroallergens (i.e. pollen) increase; however, not all environmental factors were explored equally. In specific, studies that were delimited to evaluating particulate matter (PM) reported a consistent association with suicidality. We also provide a brief description of putative mechanisms (e.g. inflammation and neurotransmitter dysregulation) that may mediate the association between air pollution, aeroallergens and suicidality.

CONCLUSION

Available evidence suggests that exposure to harmful air quality may be associated with suicidality. There are significant public health implications which are amplified in regions and countries with greater levels of air pollution and aeroallergens. In addition, those with atopic sensitivity may represent a specific subgroup that is at risk.

Treatment with a GLP-1R agonist over four weeks promotes weight loss-moderated changes in frontal-striatal brain structures in individuals with mood disorders

Cognitive deficits are a core feature across psychiatric disorders. Emerging evidence indicates that metabolic pathways are highly relevant for the substrates and phenomenology of the cognitive domain. Herein, we aimed to determine the effects of liraglutide, a GLP-1R agonist, on brain structural/volumetric parameters in adults with a mood disorder. This is the secondary analysis of a 4-week, pilot, proof-of-concept, open-label study. Participants (N=19) exhibiting impairments in executive function with either major depressive disorder (MDD) or bipolar disorder (BD) were recruited. Liraglutide 1.8mg/day was added as an adjunct to existing pharmacotherapy. Structural magnetic resonance imaging (MRI) scanning was obtained at baseline and endpoint. Results showed that at endpoint there was significant weight loss (mean: 3.15%; p<0.001). Changes in frontal and striatal volumes were significantly correlated with changes in body mass index (BMI), indicating the weight loss was associated with volume increase in most regions (e.g. r=-0.561, p=0.042 in the left superior frontal area). After adjusting for intracranial volume, age, gender, and BMI, we observed significant changes from baseline to endpoint in multiple regions (e.g. RR: 1.011, p=0.049 in the left rostral middle frontal area). Changes in regional volumes were associated with improvement in executive function (e.g. r=0.698, p=0.003 for the right superior frontal area). Adjunctive liraglutide results in clinically significant weight loss, with corresponding improvement in cognitive function; changes in cognitive function were partially moderated by changes in brain morphometry, underscoring the interrelationship between weight and brain structure/function.

Repurposing of Anti-Diabetic Agents for the Treatment of Cognitive Impairment and Mood Disorders

Impairments in cognitive function represent a consistent, non-specific, and clinically significant feature in metabolic, mood, and dementing disorders. The foregoing observation is instantiated by evidence demonstrating that these disorders share pathophysiological mechanisms including, but not limited to, aberrant insulin signaling, inflammation, and glucocorticoid activity. Moreover, these mechanisms have been consistently reported to increase vulnerability to and/or exacerbate impairments in cognitive function. Notwithstanding evidence suggesting a bidirectional relationship between disturbances in the metabolic milieu, mood, and increased risk for dementia, efficacious treatments that target cognitive impairments in these populations do not presently exist. Taken together, it is proposed that anti-diabetic agents may aid the management of mood disorders and future risk for dementia through disease modification by targeting underlying pathophysiological mechanisms (e.g., aberrant metabolic function) rather than focusing solely on symptom mitigation. The current aim is to provide a brief narrative review of extant studies that report on the potential neurotherapeutic effects of anti-diabetic agents on disturbances in mood and impairments in cognitive function.

Strategies to mitigate dissociative and psychotomimetic effects of ketamine in the treatment of major depressive episodes: a narrative review

Objectives Replicated evidence has demonstrated that ketamine exerts rapid-acting and potent antidepressant effects. Notwithstanding, its promise to mitigate depressive symptoms and suicidality in antidepressant-resistant populations, several limitations and safety concerns accompany ketamine including, but not limited to, the potential for abuse and psychotomimetic/dissociative experiences. The focus of the current narrative review is to synthesise available evidence of strategies that may mitigate and fully prevent treatment-emergent psychotomimetic and dissociative effects associated with ketamine administration. Methods PubMed, Google Scholar and ClinicalTrials.gov were searched for relevant articles. Results Potential avenues investigated to minimise psychotomimetic effects associated with ketamine administration include the following: (1) altering dosing and infusion rates; (2) route of administration; (3) enantiomer choice; (4) co-administration with mood stabilisers of antipsychotics; and (5) use of alternative N-methyl-d-aspartate (NMDA)-modulating agents. Emerging evidence indicates that dissociative experiences can be significantly mitigated by using an intranasal route of administration, lower dosages, or use of alternative NMDA-modulating agents, namely lanicemine (AZD6765) and GLYX-13. Conclusions Currently, intranasal administration presents as the most promising strategy to mitigate dissociative and psychotomimetic effects; however, studies of strategies to mitigate the adverse events of ketamine are limited in number and quality and thus further investigation is still needed.

The THINC-Integrated Tool (THINC-it) Screening Assessment for Cognitive Dysfunction: Validation in Patients With Major Depressive Disorder

OBJECTIVE

To validate the THINC-integrated tool (THINC-it)-a freely available, patient-administered, computerized screening tool integrating subjective and objective measures of cognitive function in adults with major depressive disorder (MDD).

METHODS

Subjects aged 18 to 65 years (n = 100) with recurrent MDD experiencing a major depressive episode of at least moderate severity were evaluated and compared to age-, sex-, and education-matched healthy controls (n = 100). Between January and June 2016, subjects completed the THINC-it, which includes variants of the Choice Reaction Time Identification Task (IDN), One-Back Test, Digit Symbol Substitution Test, Trail Making Test-Part B, and the Perceived Deficits Questionnaire for Depression-5-item (PDQ-5-D).

RESULTS

The THINC-it required approximately 10 to 15 minutes for administration and was capable of detecting cognitive deficits in adults with MDD. A total of 44.4% of adults with MDD exhibited cognitive performance at ≥ 1.0 SD below that of healthy controls on standardized mean scores of the THINC-it. Concurrent validity of the overall tool, based on a calculated composite score, was acceptable (r = 0.539, P < .001). Concurrent validity of the component tests ranged from -0.083 (IDN) to 0.929 (PDQ-5-D). Qualitative survey results indicated that there was a high level of satisfaction and perceived value in administering the THINC-it regarding its impact on the appropriateness and quality of care being received.

CONCLUSIONS

The THINC-it is a valid and sensitive tool for detecting cognitive dysfunction in adults with MDD that is free, easy to use, and rapidly administered. The THINC-it should be incorporated into the assessment and measurement of all patients with MDD, particularly among those with enduring functional impairment.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02508493.

Cannabidiol in medical marijuana: Research vistas and potential opportunities

The high and increasing prevalence of medical marijuana consumption in the general population invites the need for quality evidence regarding its safety and efficacy. Herein, we synthesize extant literature pertaining to the phytocannabinoid cannabidiol (CBD) and its brain effects. The principle phytocannabinoid Δ⁹-tetrahydrocannabinol (Δ⁹-THC) and CBD are the major pharmacologically active cannabinoids. The effect of CBD on brain systems as well as on phenomenological measures (e.g. cognitive function) are distinct and in many cases opposite to that of Δ⁹-THC. Cannabidiol is without euphoriant properties, and exerts antipsychotic, anxiolytic, anti-seizure, as well as anti-inflammatory properties. It is essential to parcellate phytocannabinoids into their constituent moieties as the most abundant cannabinoid have differential effects on physiologic systems in psychopathology measures. Disparate findings and reports related to effects of cannabis consumption reflect differential relative concentration of Δ⁹-THC and CBD. Existing literature, notwithstanding its deficiencies, provides empirical support for the hypothesis that CBD may exert beneficial effects on brain effector systems/substrates subserving domain-based phenomenology. Interventional studies with purified CBD are warranted with a call to target-engagement proof-of-principle studies using the research domain criteria (RDoC) framework.

A randomized, double-blind, placebo-controlled, crossover trial evaluating the effect of intranasal insulin on cognition and mood in individuals with treatment-resistant major depressive disorder

BACKGROUND

Cognitive dysfunction in major depressive disorder (MDD) is identified as a primary therapeutic target; no current treatment is approved for the treatment of cognitive dysfunction in MDD. We examined whether intranasal insulin offered a beneficial effect across measures of cognitive function in adults with MDD.

METHODS

Thirty-five adults (18-65 years of age: 47.09±9.89) meeting criteria for a major depressive episode as per the Diagnostic and Statistical Manual (DSM)-IV-Treatment Revised were included in this randomized, double blind, placebo-controlled, crossover design study. Subjects were not stratified based on baseline cognitive deficit. Subjects were randomized to 4 weeks of either intranasal insulin 40 International Units (IU) taken four times a day (i.e., morning, afternoon, evening, and before bed) (QID) (n=19) or placebo (n=16).

RESULTS

No between group differences were observed in change from baseline on total Montgomery Åsberg Depression Rating Scale (MADRS) score (25.98±2.81), in either of the Positive or Negative subscales of the Positive and Negative Affect Schedule (PANAS), or on a global index of neurocognition. The possibility of practice and/or carry over effect could not be excluded. Methodological refinement (e.g., stratification of subjects based on baseline cognitive deficit) may have augmented assay sensitivity.

CONCLUSION

Intranasal insulin did not demonstrate statistically significant improvements on overall mood, aspects of emotional processing, neurocognitive function, or self-reported quality of life patient reported outcomes.

The association between insulin resistance and depression in the Korean general population

BACKGROUND

Previous studies showed that the insulin resistance (IR) could be related to depression. However, this association is still equivocal in the general population. Herein, we aimed to investigate the association between IR and depressive symptoms in a large sample in South Korea.

METHODS

A cross-sectional study was carried out for 165,443 Korean men and women who received a health checkup including various clinical parameters and the Center for Epidemiologic Studies Depression scales (CES-D). Subjects were stratified into subgroups by CES-D score, sex, age, and presence of diabetes. The odd ratios (ORs) for homeostasis model assessment of insulin resistance (HOMA-IR) were compared between groups using multivariable logistic regression analyses.

RESULTS

After adjusting covariates (e.g. smoking, family income, marriage state, unemployment status, average alcohol use, BMI, physical activity, systolic blood pressure, diabetes), increased IR was weakly associated with greater depressive symptoms (adjusted OR=1.01 [95% CI 1.0001-1.03]). Subgroup analysis revealed this association was statistically significant in females (adjusted OR=1.03, [95% CI 1.001-1.06]), non-diabetic group (adjusted OR=1.04, [95% CI 1.02-1.06]), and young participants under the age of thirty (adjusted OR=1.17, [95% CI 1.07-1.27]). But we couldn't find significant association in diabetic and middle to elderly participants.

CONCLUSIONS

This study demonstrates that there is a relationship between IR and depressive symptoms in the Korean general population. Results from this epidemiological study revealed that young adults and non-diabetic individuals with increased IR may be related with depressive symptoms.

Pain and major depressive disorder: Associations with cognitive impairment as measured by the THINC-integrated tool (THINC-it)

OBJECTIVES

To examine the role of pain on cognitive function in adults with major depressive disorder (MDD).

METHODS

Adults (18-65) with a Diagnostic and Statistical Manual - Fifth Edition (DSM-5)-defined diagnosis of MDD experiencing a current major depressive episode (MDE) were enrolled (n_MDD=100). All subjects with MDD were matched in age, sex, and years of education to healthy controls (HC) (n_HC=100) for comparison. Cognitive function was assessed using the recently validated THINC-integrated tool (THINC-it), which comprises variants of the choice reaction time (i.e., THINC-it: Spotter), One-Back (i.e., THINC-it: Symbol Check), Digit Symbol Substitution Test (i.e., THINC-it: Codebreaker), Trail Making Test - Part B (i.e., THINC-it: Trails), as well as the Perceived Deficits Questionnaire for Depression - 5-item (i.e., THINC-it: PDQ-5-D). A global index of objective cognitive function was computed using objective measures from the THINC-it, while self-rated cognitive deficits were measured using the PDQ-5-D. Pain was measured using a Visual Analogue Scale (VAS). Regression analyses evaluated the role of pain in predicting objective and subjective cognitive function.

RESULTS

A significant between-group differences on the VAS was observed (p<0.001), with individuals with MDD reporting higher pain severity as evidenced by higher scores on the VAS than HC. Significant interaction effects were observed between self -rated cognitive deficits and pain ratings (p<0.001) on objective cognitive performance (after adjusting for MADRS total score), suggesting that pain moderates the association between self-rated and objective cognitive function.

CONCLUSIONS

Results indicated that pain is associated with increased self-rated and objective cognitive deficits in adults with MDD.

IMPLICATIONS

The study herein provides preliminary evidence demonstrating that adults with MDD reporting pain symptomatology and poorer subjective cognitive function is predictive of poorer objective cognitive performance. THINC-it is capable of detecting cognitive dysfunction amongst adults with MDD and pain.

Liraglutide promotes improvements in objective measures of cognitive dysfunction in individuals with mood disorders: A pilot, open-label study

BACKGROUND

There is a paucity of treatments that are capable of reliably and robustly improving cognitive function in adults with mood disorders. Glucagon-like peptide-1 is synthesized centrally and its receptors are abundantly expressed in neural circuits subserving cognitive function. We aimed to determine the effects of liraglutide, a GLP-1 receptor (GLP-1R) agonist, on objective measures of cognition in adults with a depressive or bipolar disorder.

METHODS

In this 4-week, pilot, open-label, domain-based study (e.g. cognition), we recruited 19 individuals with major depressive disorder (MDD) or bipolar disorder (BD) and an impairment in executive function, defined as a below-average performance in the Trail Making Test-B (TMTB). Liraglutide 1.8mg/day was added as an adjunct to existing pharmacotherapy.

RESULTS

Participants had significant increases from baseline to week 4 in the TMTB standard score (age and education corrected) (Cohen's d=0.64, p=0.009) and in a composite Z-score comprising multiple cognitive tests (i.e. Digit Symbol Substitution Test, Rey Auditory Verbal Learning Test, Stroop test) (Cohen's d=0.77, p<0.001). Neither changes in mood rating scales nor metabolic parameters were associated with changes in cognitive performance (all p>0.05); however baseline insulin resistance (IR) and body mass index (BMI) moderated the changes in the composite Z-score (p=0.021 and p=0.046, respectively), indicating larger responses in individuals with higher IR and BMI at baseline. There was a significant increase in lipase (p<0.001), but individual values were above the upper limit of normality.

LIMITATIONS

Small sample size, open-label design, lack of a placebo group.

CONCLUSIONS

Liraglutide was safe and well tolerated by a sample of non-diabetic individuals with mood disorders and had beneficial effects on objective measures of cognitive function. Larger studies with controlled trial designs are necessary to confirm and expand the results described herein.

Assessing and measuring cognitive function in major depressive disorder

Cognitive dysfunction is a major component of major depressive disorder (MDD). No 'gold-standard' tool exists for the assessment of cognitive dysfunction for adults with MDD. The use of measurement-based care to improve treatment outcomes invites the need for a systematic screening, evaluation and measurement tool. The aim herein was to provide a succinct summary of literature documenting clinical implication of cognitive dysfunction in MDD, and a review of available screening, diagnostic and measurement tools for cognitive dysfunction in MDD is provided. We also take the opportunity to introduce a screening tool (ie, the THINC-it tool) targeted at addressing the unmet needs. We found that there are limitations to the current measurement scales; for example, many are not targeted for MDD and not all digitally available tests are free of charge. Furthermore, the spectrum of cognitive dysfunction in MDD is poorly represented by the existing tests and as such, there is a lack of sensitivity in the ability to screen a patient with MDD for a cognitive dysfunction. Recognising and addressing the limitations in the current screening techniques for cognitive dysfunction as well as being presented with the current tools available provides the ability to perform an educated cognitive screening for a patient with MDD.

The prevalence and clinical characteristics associated with Diagnostic and Statistical Manual Version-5-defined anxious distress specifier in adults with major depressive disorder: results from the International Mood Disorders Collaborative Project

OBJECTIVES

The aim of the study was to evaluate the prevalence of and illness characteristics in adults with major depressive disorder (MDD) with anxious distress specifier (ADS) enrolled in the International Mood Disorders Collaborative Project, which is a collaborative research platform at the Mood Disorders Psychopharmacology Unit, University of Toronto, Canada and the Cleveland Clinic, Cleveland, Ohio, USA.

METHODS

Data from participants who met criteria for a current major depressive episode as part of MDD (n = 830) were included in this post hoc analysis. Diagnostic and Statistical Manual Version-5-defined ADS was operationalized as the presence of at least two out of three proxy items instead of two out of five specifiers.

RESULTS

A total of 464 individuals (i.e. 56%) met criteria for ADS. There were no between-group differences in sociodemographic variables (e.g. gender, employment, marital status). Greater severity of illness was observed in adults with ADS as evidenced by a higher number of hospitalizations, higher rates of suicidal ideation, greater depressive symptom severity, greater workplace impairment, decreased quality of life, and greater self-reported cognitive impairment.

CONCLUSIONS

Our findings underscore the importance of evaluating ADS in adults with MDD as its presence identifies a subpopulation with greater illness-associated burden and hazards.

Binge eating in adults with mood disorders: Results from the International Mood Disorders Collaborative Project

A post hoc analysis was conducted using data from participants (N=631) with a DSM-IV-TR defined diagnosis of major depressive disorder (MDD) or bipolar disorder (BD) who were enrolled in the International Mood Disorders Collaborative Project (IMDCP) between January 2008 and July 2013. It was determined that 20.6% of adults with mood disorders as part of the IMDCP fulfilled criteria for binge eating behaviour (BE). A higher percentage of individuals with BD met criteria for BE when compared to MDD (25.4% vs. 16%; p=0.004) Univariate analyses indicated that individuals with a mood disorder (i.e., MDD or BD) and BE had greater scores on measures of anxiety severity (p=0.013) and higher rates of lifetime and current substance dependence, lifetime alcohol abuse (p=0.007, p=0.006, and p=0.015, respectively), Attention Deficit Hyperactivity Disorder (ADHD) (p=0.018) and measures of neuroticism (p=0.019). Individuals with a mood disorder and concurrent BE had lower scores on measures of conscientiousness (p=0.019). Individuals meeting criteria for BE were also significantly more likely to be obese (i.e., BMI≥30kg/m²) (50% vs. 25.5%; p<0.001). Binge eating is common amongst adults utilising tertiary care services principally for a mood disorder. The presence of BE identifies a subset of adults with mood disorders who have greater illness complexity as evidenced by course of illness variables and comorbidity. Screening for BE amongst individuals with mood disorders is warranted; parsing neurobiological substrates subserving non-homeostatic eating behaviour amongst individuals with mood disorders is a future research vista.

Metformin: repurposing opportunities for cognitive and mood dysfunction

BACKGROUND

Cognitive deficits differentially affect individuals with type 2 diabetes mellitus (T2DM) and mood disorders. Accumulating evidence implicates disturbances in metabolism as salient to cognitive function. Thus, the mitigation of metabolic disturbances may preserve or ameliorate cognitive function. This review aims to evaluate available evidence investigating the effects of metformin on cognitive function as well as summarize putative mechanistic properties related to these clinical effects.

METHODS

A PubMed search was conducted using the search words including, but not limited to: metformin, Major Depressive Disorder, type 2 diabetes mellitus, and cognitive dysfunction. All English language articles published from 1990 to July 2014 were reviewed.

RESULTS

Extant preclinical and clinical data have been mixed, wherein both cognitive disruption and pro-cognitive effects have been reported with the administration of metformin. Sound mechanistic evidence supports metformin as a treatment; however, the heterogeneity of study designs has contributed to an inability to arrive at an unequivocal conclusion regarding metformin effects upon cognition.

CONCLUSION

Available evidence does not provide a robust signal for improvement in cognition in either mood disorder or T2DM samples. Notwithstanding, it is premature to label metformin as a "no-go" agent for further testing and development for cognitive dysfunction. A well designed, proof-of-concept trial of metformin investigating its possible cognitive effects in mood disorders is therefore warranted.

The prevalence and illness characteristics of DSM-5-defined "mixed feature specifier" in adults with major depressive disorder and bipolar disorder: Results from the International Mood Disorders Collaborative Project

BACKGROUND

A substantial proportion of individuals with mood disorders present with sub-syndromal hypo/manic features. The objective of this analysis was to evaluate the prevalence and illness characteristics of the Diagnostic and Statistical Manual Version-5 (DSM-5) - defined mixed features specifier (MFS) in adults with major depressive disorder (MDD) and bipolar disorder (BD).

METHOD

Data from participants who met criteria for a current mood episode as part of MDD (n=506) or BD (BD-I: n=216, BD-II: n=130) were included in this post-hoc analysis. All participants were enrolled in the International Mood Disorders Collaborative Project (IMDCP): a collaborative research platform at the Mood Disorders Psychopharmacology Unit, University of Toronto and the Cleveland Clinic, Cleveland, Ohio. Mixed features specifier was operationalized as a score ≥ 1 on 3 or more select items on the Young Mania Rating Scale (YMRS) or ≥ 1 on 3 select items of the Montgomery Åsberg Depression Rating Scale (MADRS) or Hamilton Depression Rating Scale (HAMD-17) during an index major depressive episode (MDE) or hypo/manic episode, respectively.

RESULTS

A total of 26.0% (n=149), 34.0% (n=65), and 33.8% (n=49) of individuals met criteria for MFS during an index MDE as part of MDD, BD-I and BD-II, respectively. Mixed features specifier during a hypo/manic episode was identified in 20.4% (n=52) and 5.1% (n=8) in BD-I and BD-II participants, respectively. Individuals with MDE-MFS as part of BD or MDD exhibited a more severe depressive phenotype (p=0.0002 and p<0.0002, respectively) and reported a higher rate of alcohol/substance use disorder in the context of BD but not MDD (p=0.002). Individuals with MFS were more likely to have co-existing heart disease suggestive of a distinct pattern of comorbidity and neurobiology.

LIMITATIONS

Data were post-hoc and obtained from individuals utilizing a university-based mood disorder centre which may affect generalizability.

CONCLUSIONS

Diagnostic and Statistical Manual Version-5-defined MFS is common during an MDE as part of MDD and BD. The presence of MFS identifies a subgroup of individuals with greater illness complexity and possibly a higher rate of cardiovascular comorbidity. The results herein underscore the common occurrence of MFS in adults with either BD or MDD. Moreover, the results of our analysis indicate that adults with mood disorders and MFS have distinct clinical characteristics and comorbidity patterns.

Inflamed moods: a review of the interactions between inflammation and mood disorders

Mood disorders have been recognized by the World Health Organization (WHO) as the leading cause of disability worldwide. Notwithstanding the established efficacy of conventional mood agents, many treated individuals continue to remain treatment refractory and/or exhibit clinically significant residual symptoms, cognitive dysfunction, and psychosocial impairment. Therefore, a priority research and clinical agenda is to identify pathophysiological mechanisms subserving mood disorders to improve therapeutic efficacy. During the past decade, inflammation has been revisited as an important etiologic factor of mood disorders. Therefore, the purpose of this synthetic review is threefold: 1) to review the evidence for an association between inflammation and mood disorders, 2) to discuss potential pathophysiologic mechanisms that may explain this association and 3) to present novel therapeutic options currently being investigated that target the inflammatory-mood pathway. Accumulating evidence implicates inflammation as a critical mediator in the pathophysiology of mood disorders. Indeed, elevated levels of pro-inflammatory cytokines have been repeatedly demonstrated in both major depressive disorder (MDD) and bipolar disorder (BD) patients. Further, the induction of a pro-inflammatory state in healthy or medically ill subjects induces 'sickness behavior' resembling depressive symptomatology. Potential mechanisms involved include, but are not limited to, direct effects of pro-inflammatory cytokines on monoamine levels, dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, pathologic microglial cell activation, impaired neuroplasticity and structural and functional brain changes. Anti-inflammatory agents, such as acetyl-salicylic acid (ASA), celecoxib, anti-TNF-α agents, minocycline, curcumin and omega-3 fatty acids, are being investigated for use in mood disorders. Current evidence shows improved outcomes in mood disorder patients when anti-inflammatory agents are used as an adjunct to conventional therapy; however, further research is needed to establish the therapeutic benefit and appropriate dosage.

Advancing biomarker research: utilizing 'Big Data' approaches for the characterization and prevention of bipolar disorder

OBJECTIVE

To provide a strategic framework for the prevention of bipolar disorder (BD) that incorporates a 'Big Data' approach to risk assessment for BD.

METHODS

Computerized databases (e.g., Pubmed, PsychInfo, and MedlinePlus) were used to access English-language articles published between 1966 and 2012 with the search terms bipolar disorder, prodrome, 'Big Data', and biomarkers cross-referenced with genomics/genetics, transcriptomics, proteomics, metabolomics, inflammation, oxidative stress, neurotrophic factors, cytokines, cognition, neurocognition, and neuroimaging. Papers were selected from the initial search if the primary outcome(s) of interest was (were) categorized in any of the following domains: (i) 'omics' (e.g., genomics), (ii) molecular, (iii) neuroimaging, and (iv) neurocognitive.

RESULTS

The current strategic approach to identifying individuals at risk for BD, with an emphasis on phenotypic information and family history, has insufficient predictive validity and is clinically inadequate. The heterogeneous clinical presentation of BD, as well as its pathoetiological complexity, suggests that it is unlikely that a single biomarker (or an exclusive biomarker approach) will sufficiently augment currently inadequate phenotypic-centric prediction models. We propose a 'Big Data'- bioinformatics approach that integrates vast and complex phenotypic, anamnestic, behavioral, family, and personal 'omics' profiling. Bioinformatic processing approaches, utilizing cloud- and grid-enabled computing, are now capable of analyzing data on the order of tera-, peta-, and exabytes, providing hitherto unheard of opportunities to fundamentally revolutionize how psychiatric disorders are predicted, prevented, and treated. High-throughput networks dedicated to research on, and the treatment of, BD, integrating both adult and younger populations, will be essential to sufficiently enroll adequate samples of individuals across the neurodevelopmental trajectory in studies to enable the characterization and prevention of this heterogeneous disorder.

CONCLUSIONS

Advances in bioinformatics using a 'Big Data' approach provide an opportunity for novel insights regarding the pathoetiology of BD. The coordinated integration of research centers, inclusive of mixed-age populations, is a promising strategic direction for advancing this line of neuropsychiatric research.

Predominant polarity as a course specifier for bipolar disorder: a systematic review

BACKGROUND

Predominant polarity (PP) is a proposed course specifier for bipolar disorder, which was not incorporated in the DSM-5 as a descriptor for the nosology of bipolar disorder (BD). Here we perform a systematic review of original studies about PP.

METHODS

A computerized search of MEDLINE/Pubmed, EMBASE and Web of Science databases from inception to October 6th, 2013 was performed with keywords, including 'bipolar disorder', 'polarity' and 'predominant polarity'.

RESULTS

A total of 19 studies met inclusion criteria. A unifying definition and conceptualization for PP is lacking. A PP is found in approximately half of BD patients. Most studies that included type I BD patients found the manic PP to be more prevalent, while studies that included type II BD participants found a higher prevalence of depressive PP. The depressive PP has been consistently associated with a depressive onset of illness, a delayed diagnosis of BD, type II BD and higher rates of suicidal acts. The manic PP is associated with a younger onset of illness, a first episode manic/psychotic and a higher rate of substance abuse. Evidence suggests that PP may influence responses to acute treatment for bipolar depression. Furthermore, evidences indicate that PP should be considered for the selection of maintenance treatments for BD.

LIMITATIONS

There are few prospective studies on PP. There were disparate definitions for PP across studies.

CONCLUSIONS

The concept of PP provides relevant information for clinicians. Future studies should investigate the genetic and biological underpinnings of PP.

Diabetes mellitus and disturbances in brain connectivity: a bidirectional relationship?

Diabetes mellitus (DM) is associated with deficits across multiple cognitive domains. The observed impairments in cognitive function are hypothesized to be subserved by alterations in brain structure and function. Several lines of evidence indicate that alterations in glial integrity and function, as well as abnormal synchrony within brain circuits and associated networks, are observed in adults with DM. Microangiopathy and alterations in insulin homeostasis appear to be principal effector systems, although a unitary explanation subsuming the complex etiopathology of white matter in DM is unavailable. A contemporary model of disease pathophysiology for several mental disorders, including but not limited to mood disorders, posits abnormalities in the synchronization of cellular systems in circuits. The observation that similar abnormalities occur in diabetic populations provides the basis for hypothesizing the convergence of pathoetiological factors. Herein, we propose that abnormal structure, function and chemical composition as well as synchrony within and between circuits is an accompaniment of DM and is shared in common with several mental disorders.

Sex differences in rates of obesity in bipolar disorder: postulated mechanisms

OBJECTIVE

The increased standardized mortality ratio (SMR) from cardiovascular disease (CVD) in women with bipolar disorder (BD), relative to men with BD and individuals of both sexes in the general population, provides the impetus to identify factors that contribute to the differential association of obesity with BD in women.

METHODS

We conducted a selective PubMed search of English-language articles published from September 1990 to June 2012. The key search terms were bipolar disorder and metabolic syndrome cross-referenced with gender, sex, obesity, diabetes mellitus, hypertension, and dyslipidemia. The search was supplemented with a manual review of relevant article reference lists. Articles selected for review were based on author consensus, the use of a standardized experimental procedure, validated assessment measures, and overall manuscript quality.

RESULTS

It is amply documented that adults with BD are affected by the metabolic syndrome at a rate higher than the general population. Women with BD, when compared to men with BD and individuals of both sexes in the general population, have higher rates of abdominal obesity. The course and clinical presentation of BD manifest differently in men and women, wherein women exhibit a higher frequency of depression predominant illness, a later onset of BD, more seasonal variations in mood disturbance, and increased susceptibility to relapse. Phenomenological factors can be expanded to include differences in patterns of comorbidity between the sexes among patients with BD. Other factors that contribute to the increased risk for abdominal obesity in female individuals with BD include reproductive life events, anamnestic (e.g., sexual and/or physical abuse), lifestyle, and iatrogenic.

CONCLUSIONS

A confluence of factors broadly categorized as broad- and sex-based subserve the increased rate of obesity in women with BD. It remains a testable hypothesis that the increased abdominal obesity in women with BD mediates the increased SMR from CVD. A clinical recommendation that emerges from this review is amplified attention to the appearance, or history, of factors that conspire to increase obesity in female patients with BD.