Enhanced working and verbal memory after lamotrigine treatment in pediatric bipolar disorder

Neuroimaging alterations associated with medication use in early-onset bipolar disorder: An updated review

BACKGROUND

Pediatric bipolar disorder (PBD) is a severe disorder characterized by mood fluctuations starting at a young age. Several neuroimaging studies revealed a specific biological signature of PBD involving alterations in the amygdala and prefrontal regions. Considering the growing concerns regarding the effects of PBD treatments on developing brains, this review aims to provide an overview of the studies investigating the effect of mood stabilizers, antipsychotics, and anticonvulsants on neuroimaging findings in PBD.

METHODS

We searched PubMed, Scopus, and Web of Science to identify all structural magnetic resonance imaging (sMRI), functional magnetic resonance imaging (fMRI), and diffusion tensor imaging (DTI) studies exploring the effects of medications on neuroimaging findings in PBD. A total of 18 studies met our inclusion criteria (fMRI n = 11, sMRI n = 6, DTI n = 1).

RESULTS

Although the findings varied highly across the studies, some investigations consistently indicated that medications primarily affect the prefrontal cortex and the amygdala. Moreover, despite some exceptions, the reported medication effects predominantly lean towards structural and functional normalization.

LIMITATIONS

The reviewed studies differ in methods, medications, and fMRI paradigms. Furthermore, most studies used observational approaches with small sample sizes, minimizing the statistical power.

CONCLUSIONS

Evidence suggests the potential of antipsychotics and mood stabilizers to modulate the neuroimaging findings in PBD patients, mostly normalizing brain structure and function in key mood-regulating regions.

An update on potential pharmacotherapies for cognitive impairment in bipolar disorder

INTRODUCTION

Cognitive impairment is a core feature of bipolar disorder (BD) that impedes recovery by preventing the return to optimal socio-occupational functioning and reducing quality of life. Presently, there are no efficacious treatments for cognitive impairment in BD, but many pharmacological interventions are being considered as they have the potential to target the underlying pathophysiology of the disorder.

AREAS COVERED

This review summarizes the available evidence for pharmacological interventions for cognitive impairment in bipolar disorder. We searched PubMed, MedLine, and PsycInfo from inception to December 1^st, 2022. Traditional treatments, such as lithium, anticonvulsants (lamotrigine), antipsychotics (aripiprazole, asenapine, cariprazine, lurasidone, and olanzapine), antidepressants (vortioxetine, fluoxetine, and tianeptine) and psychostimulants (modafinil), and emerging interventions, such as acetylcholinesterase inhibitors (galantamine and donepezil), dopamine agonists (pramipexole), erythropoietin, glucocorticoid receptor antagonists (mifepristone), immune modulators (infliximab, minocycline and doxycycline), ketamine, metabolic agents (insulin, metformin, and liraglutide), probiotic supplements, and Withania somnifera are discussed.

EXPERT OPINION

The investigation of interventions for cognitive impairment in BD is a relatively under-researched area. In the past, methodological pitfalls in BD cognition trials have also been a critical limiting factor. Expanding on the existing literature and identifying novel pharmacological and non-pharmacological treatments for cognitive impairment in BD should be a priority.

Pretreatment Alterations and Acute Medication Treatment Effects on Brain Task-Related Functional Connectivity in Youth With Bipolar Disorder: A Neuroimaging Randomized Clinical Trial

OBJECTIVE

Disruptions in cognition are a clinically significant feature of bipolar disorder (BD). The effects of different treatments on these deficits and the brain systems that support them remain to be established.

METHOD

A continuous performance test was administered to 55 healthy controls and 71 acutely ill youths with mixed/manic BD to assess vigilance and working memory during task-based functional magnetic resonance imaging studies. Patients, who were untreated for at least 7 days at baseline, and controls were scanned at pretreatment baseline and at weeks 1 and 6. After baseline testing, patients (n = 71) were randomly assigned to 6-week double-blind treatment with lithium (n = 26; 1.0-1.2 mEq/L) or quetiapine (n = 45; 400-600 mg). Weighted seed-based connectivity (wSBC) was used to assess regional brain interactions during the attention task compared with the control condition.

RESULTS

At baseline, youths with BD showed reduced connectivity between bilateral anterior cingulate cortex and both left ventral lateral prefrontal cortex and left insula and increased connectivity between left ventral lateral prefrontal cortex and left temporal pole, left orbital frontal cortex and right postcentral gyrus, and right amygdala and right occipital pole compared with controls. At 1-week follow-up, quetiapine, but not lithium, treatment led to a significant shift of connectivity patterns toward those of the controls. At week 6, compared with baseline, there was no difference between treatment conditions, at which time both patient groups showed significant normalization of brain connectivity toward that of controls.

CONCLUSION

Functional alterations in several brain regions associated with cognitive processing and the integration of cognitive and affective processing were demonstrated in untreated youths with BD before treatment. Treatment reduced several of these alterations, with significant effects at week 1 only in the quetiapine treatment group. Normalization of functional connectivity might represent a promising biomarker for early target engagement in youth with BD.

CLINICAL TRIAL REGISTRATION INFORMATION

Multimodal Neuroimaging of Treatment Effects in Adolescent Mania; https://clinicaltrials.gov/; NCT00893581.

Functional Connectivity between Task-Positive Networks and the Left Precuneus as a Biomarker of Response to Lamotrigine in Bipolar Depression: A Pilot Study

Treatment of bipolar depression poses a significant clinical challenge. Lamotrigine is one of a few efficacious drugs, however, it needs to be titrated very slowly and response can only be assessed after 10-12 weeks. With only a proportion of patients responding, an exploration of factors underlying treatment responsivity is of paramount clinical importance, as it may lead to an allocation of the drug to those most likely to respond to it. This study aimed at identifying differences in patterns of pre-treatment resting state functional connectivity (rsFC) that may underlie response to lamotrigine in bipolar depression. After a baseline MRI scan, twenty-one patients with bipolar depression were treated with lamotrigine in an open-label design; response, defined as ≥50% decrease in Hamilton Depression Rating Scale (HAMD) score, was assessed after 10-12 weeks of treatment. Twenty healthy controls had a baseline clinical assessment and scan but did not receive any treatment. Fifteen out of 21 (71%) patients responded to lamotrigine. Treatment responsivity was associated with enhanced pre-treatment rsFC of the right fronto-parietal network (FPN) and dorsal attention network (DAN) with left precuneus. The lack of treatment response was additionally characterised by reduced rsFC: of the DAN with right middle temporal gyrus; of the default mode network (DMN) with left precuneus; of the extended sensory-motor area with areas including the left hippocampus/left amygdala and left subcallosal cortex/nucleus accumbens; and of the left FPN with left inferior temporal gyrus/occipital fusiform gyrus/lateral occipital cortex. The results suggest that preserved rsFC between the FPN and DAN, the networks involved in cognitive control, and the hub of the posterior DMN, the left precuneus, may be critical for good response to lamotrigine as an add-on treatment in patients with bipolar depression. The study also suggests a more general decrease in rsFC to be related to poor treatment responsivity.

Cognitive correlates of impulsive aggression in youth with pediatric bipolar disorder and bipolar offspring

BACKGROUND

Youth with bipolar disorder (BD) and offspring of individuals with BD (BD-OFF) are characterized by higher levels of impulsive and overt aggression. The cognitive basis underlying these aggressive behaviors are not clarified in this population. The aim of this study was to investigate the relationship between cognitive alterations and aggressive behavior in youth with BD and BD-OFF.

METHODS

Forty-two youth with BD, 17 BD-OFF and 57 healthy controls (HCs) were administered the Modified Overt Aggression Scale (MOAS), the Cambridge Neuropsychological Test Automated Battery (CANTAB), the Young Mania Rating Scale (YMRS) and the Children's Depression Rating Scale (CDRS). Multiple linear regression analyses were performed in the three groups separately. In each group, tests scores from the CANTAB were predictors. MOAS subscale scores and MOAS total scores were dependent variables. Results are corrected for age, IQ and mood state.

RESULTS

Both youth with BD and BD-OFF showed positive correlations between impairment in executive functions and levels of verbal aggression. In youth with BD, altered processing of either positive and negative stimuli positively correlated with MOAS total scores, whereas in BD-OFF, such relationship was negative.

CONCLUSIONS

Impulsive aggressive behaviors in youth with BD arise from a combination of altered affective processing and executive dysfunction. The negative relationship between affective processing and aggression in BD-OFF suggested the presence of possible mechanisms of resilience in this population.

Efficacy and safety of lamotrigine in the treatment of bipolar disorder across the lifespan: a systematic review

BACKGROUND

Bipolar disorder (BD) is a cyclic mood disorder characterised by alternating episodes of mania/hypomania and depression interspersed with euthymic periods. Lamotrigine (LTG) demonstrated some mood improvement in patients treated for epilepsy, leading to clinical studies in patients with BD and its eventual introduction as maintenance therapy for the prevention of depressive relapse in euthymic patients. Most current clinical guidelines include LTG as a recommended treatment option for the maintenance phase in adult BD, consistent with its global licencing status.

AIMS

To review the evidence for the efficacy and safety of LTG in the treatment of all phases of BD.

METHODS

PubMed was searched for double-blind, randomised, placebo-controlled trials using the keywords: LTG, Lamictal, 'bipolar disorder', 'bipolar affective disorder', 'bipolar I', 'bipolar II', cyclothymia, mania, manic, depression, depressive, 'randomised controlled trial', 'randomised trial', RCT and 'placebo-controlled' and corresponding MeSH terms. Eligible articles published in English were reviewed.

RESULTS

Thirteen studies were identified. The strongest evidence supports utility in the prevention of recurrence and relapse, particularly depressive relapse, in stabilised patients. Some evidence suggests efficacy in acute bipolar depression, but findings are inconsistent. There is little or no strong evidence in support of efficacy in acute mania, unipolar depression, or rapid-cycling BD. Few controlled trials have evaluated LTG in bipolar II or in paediatric patients. Indications for safety, tolerability and patient acceptability are relatively favourable, provided there is slow dose escalation to reduce the probability of skin rash.

CONCLUSION

On the balance of efficacy and tolerability, LTG might be considered a first-line drug for BD, except for acute manic episodes or where rapid symptom control is required. In terms of efficacy alone, however, the evidence favours other medications.

Cognitive Impairment in Patients with Bipolar Disorder: Impact of Pharmacological Treatment

Bipolar disorder is an illness characterised by periods of elated and depressed mood. These mood episodes are associated with changes in cognitive function and there is evidence to suggest that cognitive dysfunction persists during euthymia. The extent to which this is a function of the illness or a result of treatment is less clear. In this narrative review, we explore the impact of commonly used medications for bipolar disorder on cognitive function. Specific impairments in executive function and verbal memory have been noted in bipolar disorder. The impact of pharmacological treatments upon cognitive function is mixed with a number of studies reporting conflicting results. Interpretation of the data is further complicated by the variety of cognitive tests employed, study design, the relatively small numbers of patients included and confounding by indication. Overall, there is some evidence that while lithium improves some cognitive domains, it impedes others. Antipsychotics may be deleterious to cognition, although this may relate to the patient population in which they are prescribed. Sodium valproate is also associated with worse cognitive outcomes, while the impact of other antiepileptics is unclear. Overall the quality of evidence is poor and is derived from a relatively small number of studies that often do not account for the significant heterogeneity of the disorder or common comorbidities. The use of consistent methodologies and measures of cognition across studies, as well as in naturalistic settings, would enable more certain conclusions to be drawn.

Bilateral Transcranial Magnetic Stimulation on DLPFC Changes Resting State Networks and Cognitive Function in Patients With Bipolar Depression

Introduction: Bipolar patients have abnormalities in cognitive functions and emotional processing. Two resting state networks (RSNs), the default mode network (DMN) and the sensorimotor network (SMN), play a decisive role in these two functions. Dorsolateral prefrontal cortex (DLPFC) is one of the main areas in the central executive network (CEN), which is linked to the activities of each of the two networks. Studies have found DLPFC abnormalities in both hemispheres of patients with bipolar depression. We hypothesized that the bilateral repetitive transcranial magnetic stimulation (rTMS) of DLPFC would produce changes in the activity of both the SMN and DMN as well as relevant cognitive function in patients with bipolar depression that responded to treatment.

Methods: 20 patients with bipolar depression underwent 10 sessions of 1 Hz rTMS on right DLPFC with subsequent 10 Hz rTMS on left DLPFC. Changes in electroencephalography resting networks between pre and post rTMS were evaluated utilizing low-resolution electromagnetic tomography (eLORETA). Depression symptom was assessed using the Beck Depression Inventory (BDI-II) and cognitive function was assessed by Verbal Fluency Test (VFT), Rey Auditory Verbal Learning Test (RAVLT), Stroop Test, and Wisconsin Card Sorting Test (WCST).

Results: Responders to rTMS showed significantly lower DMN activity at baseline and a significant decrease in SMN connectivity after treatment. Non-responders did not significantly differ from the control group at the baseline and they showed higher activity in the SMN, visual network, and visual perception network compared to control group following treatment. Bilateral rTMS resulted in significant changes in the executive functions, verbal memory, and depression symptoms. No significant changes were observed in selective attention and verbal fluency.

Conclusion: Bilateral stimulation of DLPFC, as the main node of CEN, results in changes in the activity of the SMN and consequently improves verbal memory and executive functions in patients with bipolar depression.

Cognitive deficits in bipolar disorders: Implications for emotion

Prominent cognitive deficits have been documented in bipolar disorder, and multiple studies suggest that these deficits can be observed among non-affected first-degree relatives of those with bipolar disorder. Although there is variability in the degree of cognitive deficits, these deficits are robustly relevant for functional outcomes. A separate literature documents clear difficulties in emotionality, emotion regulation, and emotion-relevant impulsivity within bipolar disorder, and demonstrates that these emotion-relevant variables are also central to outcome. Although cognitive and emotion domains are typically studied independently, basic research and emergent findings in bipolar disorder suggest that there are important ties between cognitive deficits and the emotion disturbances observed in bipolar disorder. Understanding these relationships has relevance for fostering more integrative research, for clarifying relevant aspects related to functionality and vulnerability within bipolar disorder, and for the development of novel treatment interventions. Bipolar disorder (BD) is a severe psychiatric illness that has been ranked as one of the 20 leading medical causes of disability (WHO, 2011). BD has been shown to be the psychiatric disorder with the highest rates of completed suicide across two major cohort studies (Ilgen et al., 2010; Nordentoft, Mortensen, & Pedersen, 2011). In a cross-national representative sample, one in four persons diagnosed with bipolar I disorder reported a suicide attempt (Merikangas et al., 2011). Rates of relapse remain high despite available treatments (Gitlin, Swendsen, Heller, & Hammen, 1995), and in the year after hospitalization for manic episode, two-thirds of patients do not return to work (Strakowski et al., 1998). Poverty, homelessness, and incarceration are all too common (Copeland et al., 2009). Despite the often poor outcomes, there is also evidence for outstanding accomplishments and creativity among those with milder forms of the disorder and their family members (Coryell et al., 1989; Jamison, 1993; Murray & Johnson, 2010). Some individuals appear to achieve more than the general population, suggesting the importance of understanding the variables that predict differential outcome within bipolar disorder. Within this paper, we focus on two key predictors of outcomes within bipolar disorder: cognition and emotionality. We review evidence that problems in cognition and emotionality are prominent among those diagnosed with the disorder, are not artifacts of symptom state, and relate substantively to poorer outcomes. Although traditionally studied separately, new work points toward the idea that cognition and emotionality are intricately linked within bipolar disorder. Drawing from research within bipolar disorder as well as outside of bipolar disorder, we build a model of how cognition and emotionality might be tied within bipolar disorder. We then provide suggestions for future research. Before considering findings, it is worth noting that there are several forms of the disorder, defined by varying degrees and duration of manic symptoms (APA, 2013; WHO, 1993). Manic episodes are defined by abnormally elevated or irritable mood, accompanied by increased activity and at least three symptoms (four if mood is only irritable) such as decreased need for sleep, increased self-confidence, racing thoughts or flight of ideas, rapid speech, distractibility, goal-directed activity, and engagement in pleasurable activities without regard to potential negative consequences. To meet criteria for mania, these symptoms must persist for at least one week or require hospitalization, and must lead to difficulties with functioning. If functional impairment is not more than mild and duration is between 4 and 6 days, the episode is considered a hypomanic episode. Bipolar I disorder (BD I) is diagnosed on the basis of at least one lifetime manic episode within the DSM-5 and by at least two episodes within the ICD, whereas bipolar II disorder is diagnosed on the basis of at least one hypomanic episode (and no manic episodes) as well as major depressive episodes. Cyclothymic disorder is defined by chronic but milder fluctuations between manic and depressive symptoms. Most research focuses on BD I. In addition to diagnosed samples, research has focused on those at high risk for bipolar disorder, including first-degree relatives of those with BD. This work draws on the evidence for extremely high heritability of BD I, with estimates from community-based twin studies of 0.85 (Kieseppä, Partonen, Haukka, Kaprio, & Lönnqvist, 2014). Other research has considered high risk for BD by virtue of lifetime subsyndromal symptoms, as measured by scales such as the Hypomanic Personality Scale (Eckblad & Chapman, 1986) or the General Behavior Inventory (Depue, Krauss, Spoont, & Arbisi, 1989). The study of high-risk individuals provides a way to decipher whether deficits are present before the onset of the disorder, of importance given models suggesting that episodes of the disorder may change brain function (Chang, Steiner, & Ketter, 2000; Strakowski, 2012) as well as individuals' perceptions of their emotion regulation. Beyond defining BD, it is worth defining some of the many different neuropsychological tasks that have been widely studied in BD. Perhaps no area has received more attention than executive function. Executive function is related to three core functions: 1) inhibition, the ability to suppress irrelevant information in working memory in order to accomplish an established goal; 2) working memory, the ability to hold and manipulate information in mind; and 3) cognitive flexibility, the ability to shift strategies in response to feedback (Diamond, 2013; Miyake et al., 2000). Attention (defined as the process of selecting information reception from internal or external cues) is implicated in all three of these aspects of executive function. Much of the literature we will discuss focuses on response inhibition, or the ability to suppress a prepotent response, which is considered a subtype of inhibition. Some tests measure multiple facets of executive function; for example the Trails B test likely requires working memory and cognitive flexibility (Sánchez-Cubillo et al., 2009). Aside from executive function, multiple other facets of cognition have been widely studied in bipolar disorder. Verbal and non-verbal memory are related to the ability to register, store and retrieve verbal or visual information (Lezak, 1995). Verbal fluency is measured as the number of verbal responses a person can generate to a given target, such as a specific semantic category (e.g., animals, furniture) or phonetic category (e.g., words that begin with letter F) (Diamond, 2013). Although cognitive tasks have been designed to evaluate these specific functions, it is important to note that most measures are highly inter-correlated and may assess multiple overlapping functions to some extent (for example, the Trails B test is often described as an "executive function" task, although this task likely involves both working memory and cognitive flexibility. Not surprisingly, then, some authors label the function of certain tests differently, and this is particularly evident in meta-analyses of cognition. As we describe findings in this paper, we will use the terms proposed by the authors but will also identify key tests used to define a cognitive construct. With this background in mind, we turn to a discussion of cognitive deficits, then of emotion-related traits. Our hope is that those concise summaries provide evidence for the importance of both domains, but also specificity regarding the facets of emotion and cognition that are most impaired in BD. This specificity then guides our consideration of models that integrate cognition and emotion.

Retinal photography: A window into the cardiovascular-brain link in adolescent bipolar disorder

OBJECTIVE

The burden of cardiovascular disease in bipolar disorder (BD) exceeds what can be explained by traditional cardiovascular risk factors (CVRFs), lifestyle, and/or medications. Moreover, neurocognitive deficits are a core feature of BD, and are also related to CVRFs. We examined retinal vascular photography, a proxy for cerebral microvasculature, in relation to CVRFs, peripheral microvascular function, and neurocognition among BD adolescents.

METHODS

Subjects were 30 adolescents with BD and 32 healthy controls (HC). Retinal photography was conducted using a Topcon TRC 50 DX, Type IA camera, following pupil dilation. Retinal arteriolar and venular caliber was measured, from which the arterio-venular ratio (AVR) was computed. All measures were conducted masked to participant diagnosis. Peripheral arterial tonometry measured endothelial function. Neurocognition was assessed using the Cambridge Neuropsychological Tests Automated Battery.

RESULTS

AVR was not significantly different between groups (Cohen's d=0.18, p=0.103). Higher diastolic blood pressure (BP) was associated with lower (worse) AVR in BD (r=-0.441, p=0.015) but not HC (r=-0.192, p=0.293). Similarly, in the BD group only, higher (better) endothelial function was associated with higher AVR (r=0.375, p=0.041). Hierarchical regression models confirmed that, independent of covariates, retinal vascular caliber was significantly associated with diastolic BP and endothelial function in BD. Within the BD group, mood scores were significantly negatively correlated with AVR (β=-0.451, p=0.044).

LIMITATIONS

This study's limitations include a small sample size, a cross-sectional study design, and a heterogeneous sample.

CONCLUSION

Retinal photography may offer unique insights regarding the cardiovascular and neurocognitive burden of BD. Larger longitudinal studies are warranted.

The management of cognitive impairment in bipolar disorder: current status and perspectives

Bipolar disorder (BD) is associated with important cognitive deficits that persist during the periods of remission. Although these deficits seem to play an important role in the functional impairment experienced by bipolar patients, evidence regarding their clinical management is scant. We revised the databases PubMed, MEDLINE, and clinicaltrials.gov, searching for studies focusing on the pharmacological and nonpharmacological treatment of cognitive deficits among bipolar patients. In addition, a manual search of bibliographical cross-references was performed. Currently, there is no Food and Drug Administration-approved pharmacological agent for the management of cognitive deficits in BD. A number of agents have been tested in the treatment of cognitive deficits in BD, with mixed results. Nonpharmacological interventions, such as cognitive remediation and noninvasive brain stimulation techniques, seem promising, but their role has not yet been properly explored among bipolar patients. Additional studies, aiming at evaluating the efficacy of interventions combining cognitive rehabilitation and biological treatments, are highly desirable.

Cognitive flexibility and performance in children and adolescents with threshold and sub-threshold bipolar disorder

Greater understanding of cognitive function in children and adolescents with bipolar disorder (BD) is of critical importance to improve our ability to design targeted treatments to help with real-world impairment, including academic performance. We sought to evaluate cognitive performance among children with either BD type I, II, or "not otherwise specified" (NOS) participating in multi-site Course and Outcome of Bipolar Youth study compared to typically developing controls (TDC) without psychopathology. In particular, we sought to test the hypothesis that BD-I and BD-II youths with full threshold episodes of mania or hypomania would have cognitive deficits, including in reversal learning, vs. those BD-NOS participants with sub-threshold episodes and TDCs. N = 175 participants (BD-I = 81, BD-II = 11, BD-NOS = 28, TDC = 55) completed Cambridge Neuropsychological Automated Testing Battery (CANTAB) tasks. A priori analyses of the simple reversal stage of the CANTAB intra-/extra-dimensional shift task showed that aggregated BD-I/II participants required significantly more trials to complete the task than either BD-NOS participants with sub-syndromal manic/hypomanic symptoms or than TDCs. BD participants across sub-types had impairments in sustained attention and information processing for emotionally valenced words. Our results align with prior findings showing that BD-I/II youths with distinct episodes have specific alterations in reversal learning. More broadly, our study suggests that further work is necessary to see the interaction between neurocognitive performance and longitudinal illness course. Additional work is required to identify the neural underpinnings of these differences as targets for potential novel treatments, such as cognitive remediation.

The underlying neurobiology of key functional domains in young people with mood and anxiety disorders: a systematic review

BACKGROUND

Mood and anxiety disorders are leading causes of disability and mortality, due largely to their onset during adolescence and young adulthood and broader impact on functioning. Key factors that are associated with disability and these disorders in young people are social and economic participation (e.g. education, employment), physical health, suicide and self-harm behaviours, and alcohol and substance use. A better understanding of the objective markers (i.e. neurobiological parameters) associated with these factors is important for the development of effective early interventions that reduce the impact of disability and illness persistence.

METHODS

We systematically reviewed the literature for neurobiological parameters (i.e. neuropsychology, neuroimaging, sleep-wake and circadian biology, neurophysiology and metabolic measures) associated with functional domains in young people (12 to 30 years) with mood and/or anxiety disorders.

RESULTS

Of the one hundred and thirty-four studies selected, 7.6 % investigated social and economic participation, 2.1 % physical health, 15.3 % suicide and self-harm behaviours, 6.9 % alcohol and substance use, whereas the majority (68.1 %) focussed on clinical syndrome.

CONCLUSIONS

Despite the predominance of studies that solely examine the clinical syndrome of young people the literature also provides evidence of distinct associations among objective measures (indexing various aspects of brain circuitry) and other functional domains. We suggest that a shift in focus towards characterising the mechanisms that underlie and/or mediate multiple functional domains will optimise personalised interventions and improve illness trajectories.

[Pharmacological treatment of bipolar disorder in children and adolescents]

OBJECTIVE

To review the options for acute and maintenance pharmacological treatment of bipolar disorder in children and adolescents.

METHODS

A comprehensive literature review of randomized clinical trials and open-label studies was conducted.

RESULTS

Published data from randomized controlled trials show that antipsychotics are significantly more effective than mood stabilizers in the treatment of manic or mixed episodes. Few data are available related to the treatment of depressive episodes. No trials of selective serotonin reuptake inhibitors have been conducted. Only open trials suggest that lithium and lamotrigine may be effective, whereas quetiapine did not demonstrate efficacy relative to placebo in two studies. Studies regarding the effectiveness of antipsychotics and mood stabilizers for the comorbid disorders are also few and inconclusive. Although long-term treatment is a core aspect of the management of children and adolescents with bipolar disorder, there is a lack of consistent efficacy data. If non-controlled trials suggest that lithium, lamotrigine, quetiapine, ziprazidone, and the combination of risperidone and divalproex or lithium may be useful in some conditions, only aripiprazole has shown efficacy relative to placebo for long-term symptom reduction and relapse prevention. Safety data show that the most frequently reported adverse events in children and adolescents treated with mood stabilizers are gastrointestinal and neurological, whereas use of antipsychotics is mainly related to weight gain and sedation. Lastly, while results from studies having evaluated the impact of pharmacological treatment on neuropsychological functioning are inconsistent, some of them nevertheless suggest that treatment with mood stabilizers may be associated with specific impairments.

CONCLUSION

Despite recent developments in identifying effective pharmacological interventions, numerous critical gaps remain.

Two-year follow-up of treated adolescents with early-onset bipolar disorder: Changes in neurocognition

BACKGROUND

Few studies have analyzed the course of neurocognition in treated children and adolescents with early-onset bipolar disorder (EOBD) and shown improvements in attention, working memory, and verbal memory after treatment. The aim of this study was to determine the progress over two years in neuropsychological performance of a sample of medicated adolescents with EOBD compared to healthy controls (HC).

METHODS

Twenty adolescents, diagnosed in clinical setting as DSM-IV bipolar disorder, treated for two years, euthymic, and 20 gender and age-matched HC were assessed at two moments in reasoning, verbal and visual memory, working memory, speed, visual-motor skills and executive function. Multivariate analyses of variance was carried out to analyze the differences between groups over time, and to monitor the influence of psychotic symptoms and type of mood-stabilizer.

RESULTS

The entire sample improved on verbal and visual memory tests (verbal recall p<0.01; visual recall p<0.001). Moreover, patients improved more than controls in verbal reasoning (p<0.01), working memory (p<0.01), processing speed (p<0.01) and visual-motor skills (p<0.001). Psychotic symptoms and treatment with lithium were associated with poorer development in executive control tasks.

LIMITATIONS

Sample size was small and groups were re-evaluated in slight different follow-up periods. Doses of antipsychotics drugs over time were not controlled.

CONCLUSIONS

Processing speed and visual-motor skills in the EOBD group normalized during follow-up. Executive functioning, working memory, and verbal and visual memory remained impaired in patients versus controls. The knowledge of cognitive deficits due to normal course of illness or to drug effects allows better therapeutic strategies.

Neurocognitive impairments among youth with pediatric bipolar disorder: a systematic review of neuropsychological research

BACKGROUND

Pediatric bipolar disorder (PBD) has emerged as a field of research in which neuropsychological studies are continuously providing new empirical findings. Despite this, a comprehensive framework for neurocognitive impairments is still lacking, and most of the evidence remains unconnected. We addressed this question through a systematic review of neuropsychological research, with the aim of elucidating the main issues concerning this topic.

METHOD

A comprehensive search of databases (PubMed, PsycINFO) was performed. Published manuscripts between 1990 and January 2014 were identified. Overall, 124 studies fulfilled inclusion criteria. Methodological differences between studies required a descriptive review of findings.

RESULTS

Evidence indicates that verbal/visual-spatial memory, processing speed, working memory, and social cognition are neurocognitive domains impaired in PBD youth. Furthermore, these deficits are greater among those who suffer acute affective symptoms, PBD type I, and/or attention deficit hyperactivity disorder (ADHD) comorbidity. In addition, several neurocognitive deficits imply certain changes in prefrontal cortex activity and are somewhat associated with psychosocial and academic disabilities. Strikingly, these deficits are consistently similar to those encountered in ADHD as well as severe mood dysregulation (SMD). Besides, some neurocognitive impairments appear before the onset of the illness and tend to maintain stable across adolescence. Finally, any therapy has not yet demonstrated to be effective on diminishing these neurocognitive impairments.

LIMITATIONS

More prolonged follow-up studies aimed at delineating the course of treatment and the response to it are warranted.

CONCLUSIONS

Despite noteworthy research on the neurocognitive profile of PBD, our knowledge is still lagging behind evidence from adult counterparts.

Neural correlates of treatment response in depressed bipolar adolescents during emotion processing

Depressive mood in adolescents with bipolar disorder (BDd) is associated with significant morbidity and mortality, but we have limited information about neural correlates of depression and treatment response in BDd. Ten adolescents with BDd (8 females, mean age = 15.6 ± 0.9) completed two (fearful and happy) face gender labeling fMRI experiments at baseline and after 6-weeks of open treatment. Whole-brain analysis was used at baseline to compare their neural activity with those of 10 age and sex-matched healthy controls (HC). For comparisons of the neural activity at baseline and after treatment of youth with BDd, region of interest analysis for dorsal/ventral prefrontal, anterior cingulate, and amygdala activity, and significant regions identified by wholebrain analysis between BDd and HC were analyzed. There was significant improvement in depression scores (mean percentage change on the Child Depression Rating Scale-Revised 57 % ± 28). Neural activity after treatment was decreased in left occipital cortex in the intense fearful experiment, but increased in left insula, left cerebellum, and right ventrolateral prefrontal cortex in the intense happy experiment. Greater improvement in depression was associated with baseline higher activity in ventral ACC to mild happy faces. Study sample size was relatively small for subgroup analysis and consisted of mainly female adolescents that were predominantly on psychotropic medications during scanning. Our results of reduced negative emotion processing versus increased positive emotion processing after treatment of depression (improvement of cognitive bias to negative and away from positive) are consistent with the improvement of depression according to Beck's cognitive theory.

Risk-taking behavior in juvenile myoclonic epilepsy

Objective

Patients with juvenile myoclonic epilepsy (JME) often present with risk-taking behavior, suggestive of frontal lobe dysfunction. Recent studies confirm functional and microstructural changes within the frontal lobes in JME. This study aimed at characterizing decision-making behavior in JME and its neuronal correlates using functional magnetic resonance imaging (fMRI).

Methods

We investigated impulsivity in 21 JME patients and 11 controls using the Iowa Gambling Task (IGT), which measures decision making under ambiguity. Performance on the IGT was correlated with activation patterns during an fMRI working memory task.

Results

Both patients and controls learned throughout the task. Post hoc analysis revealed a greater proportion of patients with seizures than seizure-free patients having difficulties in advantageous decision making, but no difference in performance between seizure-free patients and controls. Functional imaging of working memory networks showed that overall poor IGT performance was associated with an increased activation in the dorsolateral prefrontal cortex (DLPFC) in JME patients. Impaired learning during the task and ongoing seizures were associated with bilateral medial prefrontal cortex (PFC) and presupplementary motor area, right superior frontal gyrus, and left DLPFC activation.

Significance

Our study provides evidence that patients with JME and ongoing seizures learn significantly less from previous experience. Interictal dysfunction within “normal” working memory networks, specifically, within the DLPFC and medial PFC structures, may affect their ability to learn.

Canadian Network for Mood and Anxiety Treatments (CANMAT) and International Society for Bipolar Disorders (ISBD) collaborative update of CANMAT guidelines for the management of patients with bipolar disorder: update 2013

The Canadian Network for Mood and Anxiety Treatments published guidelines for the management of bipolar disorder in 2005, with updates in 2007 and 2009. This third update, in conjunction with the International Society for Bipolar Disorders, reviews new evidence and is designed to be used in conjunction with the previous publications.The recommendations for the management of acute mania remain largely unchanged. Lithium, valproate, and several atypical antipsychotic agents continue to be first-line treatments for acute mania. Monotherapy with asenapine, paliperidone extended release (ER), and divalproex ER, as well as adjunctive asenapine, have been added as first-line options.For the management of bipolar depression, lithium, lamotrigine, and quetiapine monotherapy, as well as olanzapine plus selective serotonin reuptake inhibitor (SSRI), and lithium or divalproex plus SSRI/bupropion remain first-line options. Lurasidone monotherapy and the combination of lurasidone or lamotrigine plus lithium or divalproex have been added as a second-line options. Ziprasidone alone or as adjunctive therapy, and adjunctive levetiracetam have been added as not-recommended options for the treatment of bipolar depression. Lithium, lamotrigine, valproate, olanzapine, quetiapine, aripiprazole, risperidone long-acting injection, and adjunctive ziprasidone continue to be first-line options for maintenance treatment of bipolar disorder. Asenapine alone or as adjunctive therapy have been added as third-line options.

Negative emotion impairs working memory in pediatric patients with bipolar disorder type I

BACKGROUND

We investigated affect recognition and the impact of emotional valence on working memory (using happy, angry, and neutral faces) in pediatric patients with bipolar disorder (BD) and healthy control (HC) subjects.

METHOD

Subjects (N=70) consisted of unmedicated patients with BD type I (BD I, n=23) and type II (BD II, n=16) and matched HC subjects (n=31). All subjects completed tasks of emotion recognition (Chicago Pediatric Emotional Acuity Task; Chicago PEAT) and working memory for happy, angry, and neutral faces (Affective N-Back Memory Task; ANMT).

RESULTS

Compared to HC subjects, BD patients performed significantly more poorly when identifying the intensity of happy and angry expressions on the Chicago PEAT, and demonstrated working-memory impairments regardless of the type of facial emotional stimuli. Pediatric BD patients displayed the most impaired accuracy and reaction time performance with negative facial stimuli relative to neutral stimuli, but did not display this pattern with positive stimuli. Only BD I patients displayed working-memory deficits, while both BD I and BD II patients displayed emotion-identification impairments. Results remained significant after controlling for co-morbid ADHD and mood state.

CONCLUSIONS

Both BD I and BD II youth demonstrate emotion-identification deficits. BD youth also demonstrate working-memory impairments for facial stimuli irrespective of emotional valence; however, working-memory deficits were the most pronounced with negative emotional stimuli. These deficits appear to be specific to BD I patients, and suggest therefore that a more severe form of illness is characterized by more severe social-cognitive impairment.

Reduced functional connectivity of prefrontal regions and amygdala within affect and working memory networks in pediatric bipolar disorder

This study examined whether adolescents with pediatric bipolar disorder (PBD) have abnormal regional functional connectivity in distributed brain networks during an affective working memory task. Adolescents with PBD (n=41) and healthy controls (HC; n=16) performed a two-back functional magnetic resonance imaging working memory task with blocks of either angry or neutral faces. Independent component analysis methodology identified two temporally independent and functionally connected brain networks that showed differential functional connectivity in PBD and HC. Within a network for "affect evaluation and regulation," PBD showed decreased functional connectivity relative to HC in regions involved in emotion processing such as the right amygdala, and in emotion regulation regions such as the right ventrolateral prefrontal cortex (VLPFC), while functional connectivity was increased in emotion evaluation regions such as the bilateral medial PFC. Furthermore, in an "Affective Working Memory Network," PBD exhibited greater connectivity relative to HC in left dorsolateral PFC (DLPFC), caudate, and right VLPFC; and simultaneously reduced connectivity in emotion processing regions, such as the right amygdala, bilateral temporal regions, and the junction of DLPFC/VLPFC, which interfaces affective and cognitive processes. Dysfunction in network engagement in PBD patients illustrates that they are expending greater effort in face emotion evaluation, while being less able to engage affect regulation regions.

Pharmacological approaches in bipolar disorders and the impact on cognition: a critical overview

OBJECTIVE

Historically, pharmacological treatments for bipolar disorders (BD) have been associated with neurocognitive side-effects. We reviewed studies which assessed the impact of several psychopharmacological drugs on the neurocognitive function of BD patients.

METHOD

The PubMed database was searched for studies published between January 1980 and February 2011, using the following terms: bipolar, bipolar disorder, mania, manic episode, or bipolar depression, cross-referenced with cognitive, neurocognitive, or neuropsychological, cross-referenced with treatment.

RESULTS

Despite methodological flaws in the older studies and insufficient research concerning the newer agents, some consistent findings emerged from the review; lithium appears to have definite, yet subtle, negative effects on psychomotor speed and verbal memory. Among the newer anticonvulsants, lamotrigine appears to have a better cognitive profile than carbamazepine, valproate, topiramate, and zonisamide. More long-term studies are needed to better understand the impact of atypical antipsychotics on BD patients' neurocognitive functioning, both in monotherapy and in association with other drugs. Other agents, like antidepressants and cognitive enhancers, have not been adequately studied in BD so far.

CONCLUSION

Pharmacotherapies for BD should be chosen to minimize neurocognitive side-effects, which may already be compromised by the disease process itself. Neurocognitive evaluation should be considered in BD patients to better evaluate treatment impact on neurocognition. A comprehensive neuropsychological evaluation also addressing potential variables and key aspects such as more severe cognitive deficits, comorbidities, differential diagnosis, and evaluation of multiple cognitive domains in longitudinal follow-up studies are warranted.

Cognitive dysfunction is worse among pediatric patients with bipolar disorder Type I than Type II

BACKGROUND

  Impaired profiles of neurocognitive function have been consistently demonstrated among pediatric patients with bipolar disorder (BD), and may aid in the identification of endophenotypes across subtypes of the disorder. This study aims to determine phenotypic cognitive profiles of patients with BD Type I and II.

METHODS

  Subjects (N = 79) consisted of BD I (n = 27) and BD II (n = 19) patients and demographic and intellectually matched healthy controls (HC; n = 33) that completed a battery of neurocognitive tasks.

RESULTS

  Bipolar disorder Type I patients performed significantly more poorly compared to HC on all domains of cognitive function including attention, executive function, working memory, visual memory, and verbal learning and memory. BD I patients also performed more poorly compared to BD II patients on all domains of cognitive functioning with the exception of working memory, whereas BD II patients did poorly relative to HC only on verbal learning and memory.

CONCLUSIONS

  Findings from the current study indicate that BD I patients are characterized by more severe cognitive impairment relative to BD II patients who show an intermediate pattern of performance between BD I patients and HC. Verbal learning and memory may effectively differentiate pediatric BD patients and controls, regardless of the subtype of BD, and may serve as a cognitive endophenotype for the disorder. Additionally, these findings move us closer to developing effective cognitive interventions tailored to specific subtypes of pediatric BD patients.

Risperidone and divalproex differentially engage the fronto-striato-temporal circuitry in pediatric mania: a pharmacological functional magnetic resonance imaging study

OBJECTIVE

The current study examined the impact of risperidone and divalproex on affective and working memory circuitry in patients with pediatric bipolar disorder (PBD).

METHOD

This was a six-week, double-blind, randomized trial of risperidone plus placebo versus divalproex plus placebo for patients with mania (n = 21; 13.6 ± 2.5 years of age). Functional magnetic resonance imaging (fMRI) outcomes were measured using a block design, affective, N-back task with angry, happy, and neutral face stimuli at baseline and at 6-week follow-up. Matched healthy controls (HC; n = 15, 14.5 ± 2.8 years) were also scanned twice.

RESULTS

In post hoc analyses on the significant interaction in a 3×2×2 analysis of variance (ANOVA) that included patient groups and HC, the risperidone group showed greater activation after treatment in response to the angry face condition in the left subgenual anterior cingulate cortex (ACC) and striatum relative to the divalproex group. The divalproex group showed greater activation relative to the risperidone group in the left inferior frontal gyrus and right middle temporal gyrus. Over the treatment course, the risperidone group showed greater change in activation in the left ventral striatum than the divalproex group, and the divalproex group showed greater activation change in left inferior frontal gyrus and right middle temporal gyrus than the risperidone group. Furthermore, each patient group showed increased activation relative to HC in fronto-striato-temporal regions over time. The happy face condition was potentially less emotionally challenging in this study and did not elicit notable findings.

CONCLUSIONS

When patients performed a working memory task under emotional duress inherent in the paradigm, divalproex enhanced activation in a fronto-temporal circuit whereas risperidone increased activation in the dopamine (D₂) receptor-rich ventral striatum. Clinical trial registration information-Risperidone and Divalproex Sodium With MRI Assessment in Pediatric Bipolar; http://www.clinicaltrials.gov; NCT00176202.

Brain functional domains inform therapeutic interventions in attention-deficit/hyperactivity disorder and pediatric bipolar disorder

A deeper understanding of how the relationships between impulsivity, reward systems and executive function deficits may be similar or different in attention-deficit/hyperactivity disorder (ADHD) and pediatric bipolar disorder (PBD) is fundamental for better defining phenotypy in these two developmental illnesses, and moving towards improved treatment and intervention. We focus our article on recent neurocognitive and neuroimaging data examining the behavioral and neural aspects of poor behavior regulation, response inhibition and reward systems in ADHD and PBD. In light of recent research evidence, we propose that the common behavioral manifestations of impulsivity in ADHD and PBD may indeed originate from different neural mechanisms mediated by altered reward systems. In order to define and differentiate these mechanisms, unlike previous approaches, our theoretical model examines the interface of the dorsal frontostriatal circuit, involved in behavior regulation, and the ventral frontostriatal circuit, which is involved in reward-related and affect processes. Preliminary evidence suggests that the neural systems involved in impulsivity, reward systems and executive function engage differently in the two illnesses. In PBD, 'emotional impulsivity' is predominantly 'bottom-up' and emotionally/motivationally driven, and stems from ventral frontostriatal circuitry dysfunction. By contrast, in ADHD 'cognitive impulsivity' is predominantly 'top-down' and more 'cognitively driven', and stems from dorsal frontostriatal dysfunction. We discuss this evidence in view of clinically relevant questions and implications for illness-based intervention. We conclude that the reward-related mechanisms underlying the interactions between executive function, behavior regulation and impulsivity in PBD and ADHD may be differentially compromised, and in accordance differently shape the clinical symptoms of impulsivity and goal-directed behavior.

Pharmacotherapy impacts functional connectivity among affective circuits during response inhibition in pediatric mania

OBJECTIVE

The aim of the current study was to determine the influence of implicated affective circuitry disturbance in pediatric bipolar disorder (PBD) on behavioral inhibition. The differential influence of an antipsychotic and an anti-epileptic medication on the functional connectivity across affective and cognitive neural operations in PBD was examined.

METHODS

This was a six-week double blind randomized fMRI trial of risperidone plus placebo vs. divalproex plus placebo for patients with mania (n=22; 13.6 ± 2.5 years). Healthy controls (HC; n=14, 14.5 ± 2.8 years) were also scanned for normative comparison. Participants performed a response inhibition fMRI task where a motor response, already 'on the way' to execution, had to be voluntarily inhibited on trials where a stop signal was presented. Independent component analysis was used to map functional connectivity across the whole brain.

RESULTS

While there were no behavioral differences between the groups at pre- or post-drug trial, there was significant improvement on manic symptoms in the patient groups. All participants engaged an evaluative affective circuit (EAC: bilateral inferior frontal gyrus, middle frontal gyrus, anterior cingulate cortex (ACC), middle temporal gyrus, insulae, caudate and putamen) and a reactive affective circuit (RAC: bilateral occipital cortex, amygdala, medial frontal gyrus and insula) during task performance. Within the EAC, post-treatment and relative to HC, greater engagement was seen in left insula in risperidone group and left subgenual ACC in divalproex group. Within the RAC, greater baseline amygdala connectivity in patients did not alter with treatment.

CONCLUSION

EAC and RAC are two key circuits that moderate emotional influence on response inhibition in PBD. Risperidone and divalproex differentially engage the EAC. Limited change in amygdala activity with treatment in all patients indicates a likely trait deficit in PBD.

Fronto-limbic dysfunction in mania pre-treatment and persistent amygdala over-activity post-treatment in pediatric bipolar disorder

RATIONALE

Neural deficits at the interface of affect and cognition may improve with pharmacotherapy in pediatric bipolar disorder (PBD).

OBJECTIVES

We examined lamotrigine treatment impact on the neural interface of working memory and affect in PBD.

METHODS

Un-medicated, acutely ill, patients with mania and hypomania (n = 17), and healthy controls (HC; n = 13; mean age = 13.36 ± 2.55) performed an affective two-back functional magnetic resonance imaging task with blocks of angry vs neutral faces (i.e., angry face condition) or happy vs neutral faces (i.e., happy face condition) before treatment and at follow-up, after 8-week treatment with second-generation antipsychotics followed by 6 weeks of lamotrigine monotherapy.

RESULTS

At baseline, for the angry face condition, PBD, relative to HC, showed reduced activation in the left ventrolateral prefrontal cortex (VLPFC) and right caudate; for the happy face condition, PBD showed increased activation in bilateral PFC and right amygdala and middle temporal gyrus. Post-treatment, PBD showed greater activation in right amygdala relative to HC for both conditions. Patients, relative to HC, exhibited greater changes over time in the right VLPFC and amygdala, left subgenual anterior cingulate cortex and left caudate for the angry face condition, and in right middle temporal gyrus for the happy face condition.

CONCLUSIONS

Pharmacotherapy resulted in symptom improvement and normalization of higher cortical emotional and cognitive regions in patients relative to HC, suggesting that the VLPFC dysfunction may be state-specific in PBD. Amygdala was overactive in PBD, relative to HC, regardless of reduction in manic symptoms, and may be a trait marker of PBD.

Double-blind randomized trial of risperidone versus divalproex in pediatric bipolar disorder: fMRI outcomes

The aim of this research was to determine the relative effects of risperidone and divalproex on brain function in pediatric mania. This is a double-blind 6-week functional magnetic resonance imaging trial with 24 unmedicated manic patients randomized to risperidone or divalproex, and 14 healthy controls (HCs) matched for IQ and demographic factors (mean age: 13.1±3.3years). A pediatric affective color matching task, in which subjects matched the color of a positive, negative or neutral word with one of two colored circles, was administered. The primary clinical measure was the Young Mania Rating Scale (YMRS). The risperidone group, relative to HC, showed an increase in activation from pre- to post-treatment in right pregenual and subgenual anterior cingulate cortex and decreased activation in bilateral middle frontal gyrus during the negative condition; and decreased activation in left inferior and medial, and right middle frontal gyri, left inferior parietal lobe, and right striatum with positive condition. In the divalproex group, relative to HC, there was an increased activation in right superior temporal gyrus in the negative condition; and in left medial frontal gyrus and right precuneus with the positive condition. Greater pre-treatment right amygdala activity with negative and positive condition in the risperidone group, and left amygdala activity with positive condition in divalproex group, predicted poor response on YMRS. Risperidone and divalproex yield differential patterns of prefrontal activity during an emotion processing task in pediatric mania. Increased amygdala activity at baseline is a potential biomarker predicting poor treatment response to both the risperidone and divalproex.

Effects of early intervention on the course of bipolar disorder: theories and realities

Given the severity and early onset of pediatric bipolar disorder, early intervention is important to bring about recovery and alter the course of the illness. There is a new and burgeoning body of literature on the biological basis of early signs of the illness and the mechanistic understanding of treatment interventions. Biological findings based on multimodal imaging, genomic studies of cellular proteins, and performance-based findings of neurocognitive studies are beginning to assemble a cohesive and interlinked model of systems neuroscience. This offers the promise of identifying biomarkers, predictors of illness, and treatment outcomes. In complement, at the tier of clinical application is a multitude of efficacy trials, yet neither a single medication nor a combination of choices seems to suffice in reality. The current review develops a point of view bridging scientific developments to where comprehensive, multipronged treatment strategies find their clinical application-a model that is similarly applicable in adult bipolar disorder.