Genetic polymorphisms in monoamine systems and outcome of cognitive behavior therapy for social anxiety disorder

Application and Mechanisms of Internet-Based Cognitive Behavioral Therapy (iCBT) in Improving Psychological State in Cancer Patients

This review article is an overview of the effectiveness of internet-based cognitive behavioral therapy (iCBT) in Improving Psychological State in Cancer Patients. iCBT's effectiveness has been investigated in treating and managing conditions like depression, psychiatric disorders, generalized anxiety disorder (GAD), panic disorder, obsessive compulsive disorder (OCD), post-traumatic stress disorder (PTSD), adjustment disorder, bipolar disorder, chronic pain, and phobias. iCBT's role in the treatment of medical conditions such as diabetes mellitus with comorbid psychiatric illnesses was also explored. We conducted a thorough literature search using PubMed, Embase, Google Scholar, and Wanfang with no restrictions on the date. iCBT's role in treating and controlling psychiatric illnesses in cancer patients has been established in the literature. Development and popularization of iCBT, treament forms of iCBT, platforms for iCBT, application of iCBT, strategies and efficacy of iCBT for insomnia in cancer patients, current status of iCBT application, and genetic researches on iCBT for anxiety disorders were all reviewed and discussed in this review. From the data compiled, we conclude that iCBT is useful in treating or improving psychological state in cancer patients.

Psychotherapies and digital interventions for OCD in adults: What do we know, what do we need still to explore?

BACKGROUND

Despite significant advances in the understanding and treatment of obsessive compulsive disorder (OCD), current treatment options are limited in terms of efficacy for symptom remission. Thus, assessing the potential role of iterative or alternate psychotherapies is important. Also, the potential role of digital technologies to enhance the accessibility of these therapies, should not be underestimated. We also need to embrace the idea of a more personalized treatment choice, being cognisant of clinical, genetic and neuroimaging predictors of treatment response.

PROCEDURES

Non-systematic review of current literature on emerging psychological and digital therapies for OCD, as well as of potential biomarkers of treatment response.

FINDINGS

A number of 'third wave' therapies (e.g., Acceptance and Commitment Therapy, Mindfulness-Based Cognitive Therapy) have an emerging and encouraging evidence base in OCD. Other approaches entail employment of elements of other psychotherapies such as Dialectical Behaviour Therapy; or trauma-focussed therapies such as Eye Movement Desensitisation and Reprocessing, and Imagery Rescripting and Narrative Therapy. Further strategies include Danger Ideation Reduction Therapy and Habit Reversal. For these latter approaches, large-scale randomised controlled trials are largely lacking, and the precise role of these therapies in treating people with OCD, remains to be clarified. A concentrated 4-day program (the Bergen program) has shown promising short- and long-term results. Exercise, music, and art therapy have not been adequately tested in people with OCD, but may have an adjunctive role. Digital technologies are being actively investigated for enhancing reach and efficacy of psychological therapies for OCD. Biomarkers, including genetic and neuroimaging, are starting to point to a future with more 'personalised medicine informed' treatment strategizing for OCD.

CONCLUSIONS

There are a number of potential psychological options for the treatment of people with OCD who do not respond adequately to exposure/response prevention or cognitive behaviour therapy. Adjunctive exercise, music, and art therapy might be useful, albeit the evidence base for these is very small. Consideration should be given to different ways of delivering such interventions, including group-based, concentrated, inpatient, or with outreach, where appropriate. Digital technologies are an emerging field with a number of potential applications for aiding the treatment of OCD. Biomarkers for treatment response determination have much potential capacity and deserve further empirical testing.

Genetics of social anxiety disorder: a systematic review

Social anxiety disorder (SAD) is a common psychiatric disorder, often associated with avoidant temperament. Research studies have implicated a strong genetic architecture of SAD. We have conducted a systematic review on the genetics of SAD and yielded 66 articles. In general, prior research studies have focused on the serotonin transporter, oxytocin receptor, brain-derived neurotrophic factor and catechol-O-methyltransferase genes. Mixed and inconsistent results have been reported. Additional approaches and phenotypes have also been investigated, including pharmacogenetics of treatment response, imaging genetics and gene-environment interactions. Future directions warrant further international collaborative efforts, deep-phenotyping of clinical characteristics including consistent and reliable measurement-based symptom severity, and larger sample sizes to ensure sufficient power for stratification due to the heterogeneity of this chronic and often debilitating condition.

Maximizing remission from cognitive-behavioral therapy in medicated adults with obsessive-compulsive disorder

Practice guidelines for adults with obsessive-compulsive disorder (OCD) recommend augmenting serotonin reuptake inhibitors (SRIs) with exposure and ritual prevention (EX/RP). However, fewer than half of patients remit after a standard 17-session EX/RP course. We studied whether extending the course increased overall remission rates and which patient factors predicted remission. Participants were 137 adults with clinically significant OCD (Yale-Brown Obsessive Compulsive Scale [Y-BOCS] score ≥18) despite an adequate SRI trial (≥12 weeks). Continuing their SRI, patients received 17 sessions of twice-weekly EX/RP (standard course). Patients who did not remit (Y-BOCS ≤12) received up to 8 additional sessions (extended course). Of 137 entrants, 123 completed treatment: 49 (35.8%) remitted with the standard course and another 46 (33.6%) with the extended course. Poorer patient homework adherence, more Obsessive-Compulsive Personality Disorder (OCPD) traits, and the Brain-Derived Neurotrophic Factor (BDNF) Val66MET genotype were associated with lower odds of standard course remission. Only homework adherence differentiated non-remitters from extended course remitters. Extending the EX/RP course from 17 to 25 sessions enabled many (69.3%) OCD patients on SRIs to achieve remission. Although behavioral (patient homework adherence), psychological (OCPD traits), and biological (BDNF genotype) factors influenced odds of EX/RP remission, homework adherence was the most potent patient factor overall.

Therapygenetic effects of 5-HTTLPR on cognitive-behavioral therapy in anxiety disorders: A meta-analysis

There is a recurring debate on the role of the serotonin transporter gene linked polymorphic region (5-HTTLPR) in the moderation of response to cognitive behavioral therapy (CBT) in anxiety disorders. Results, however, are still inconclusive. We here aim to perform a meta-analysis on the role of 5-HTTLPR in the moderation of CBT outcome in anxiety disorders. We investigated both categorical (symptom reduction of at least 50%) and dimensional outcomes from baseline to post-treatment and follow-up. Original data were obtained from ten independent samples (including three unpublished samples) with a total of 2,195 patients with primary anxiety disorder. No significant effects of 5-HTTLPR genotype on categorical or dimensional outcomes at post and follow-up were detected. We conclude that current evidence does not support the hypothesis of 5-HTTLPR as a moderator of treatment outcome for CBT in anxiety disorders. Future research should address whether other factors such as long-term changes or epigenetic processes may explain further variance in these complex gene-environment interactions and molecular-genetic pathways that may confer behavioral change following psychotherapy.

Pharmacogenetics of anxiety disorders

Anxiety disorders are common and disabling conditions the treatment of which remains a challenge. While different groups of medication are available for their treatment, a substantial proportion of patients remain refractory to pharmacotherapy. The reason for this variation in the individual response to treatment has yet to be understood; however genetic factors have been shown to play an important role. Up to now there have been limited publications about pharmacogenetics of anxiety disorders, compared to studies in depression. Published studies are focused on pharmacogenetics of antidepressants rather than being disease specific. This review summarizes pharmacogenetic findings related to the anxiolytic treatment response and their possible functional mechanisms. This inevitably focuses on genes involved in the pharmacodynamics of the medications used, along with some genes implicated in the disease process, as well as briefly mentioning genetic factors associated with psychotherapeutic response.

Internet Interventions for Adults with Anxiety and Mood Disorders: A Narrative Umbrella Review of Recent Meta-Analyses

Internet-delivered cognitive behaviour therapy (ICBT) has existed for 20 years and there are now several controlled trials for a range of problems. In this paper, we focused on recent meta-analytic reviews of the literature and found moderate to large effects reported for panic disorder, social anxiety disorder, generalized anxiety disorder, posttraumatic stress disorder, and major depression. In total, we reviewed 9 recent meta-analytic reviews out of a total of 618 meta-analytic reviews identified using our search terms. In these selected reviews, 166 studies were included, including overlap in reviews on similar conditions. We also covered a recent review on transdiagnostic treatments and 2 reviews on face-to-face v. internet treatment. The growing number of meta-analytic reviews of studies now suggests that ICBT works and can be as effective as face-to-face therapy.

Genetics of response to cognitive behavior therapy in adults with major depression: a preliminary report

Major depressive disorder is heritable and a leading cause of disability. Cognitive behavior therapy is an effective treatment for major depression. By quantifying genetic risk scores based on common genetic variants, the aim of this report was to explore the utility of psychiatric and cognitive trait genetic risk scores, for predicting the response of 894 adults with major depressive disorder to cognitive behavior therapy. The participants were recruited in a psychiatric setting, and the primary outcome score was measured using the Montgomery Åsberg Depression Rating Scale-Self Rated. Single-nucleotide polymorphism genotyping arrays were used to calculate the genomic risk scores based on large genetic studies of six phenotypes: major depressive disorder, bipolar disorder, attention-deficit/hyperactivity disorder, autism spectrum disorder, intelligence, and educational attainment. Linear mixed-effect models were used to test the relationships between the six genetic risk scores and cognitive behavior therapy outcome. Our analyses yielded one significant interaction effect (B = 0.09, p < 0.001): the autism spectrum disorder genetic risk score correlated with Montgomery Åsberg Depression Rating Scale-Self Rated changes during treatment, and the higher the autism spectrum disorder genetic load, the less the depressive symptoms decreased over time. The genetic risk scores for the other psychiatric and cognitive traits were not related to depressive symptom severity or change over time. Our preliminary results indicated, as expected, that the genomics of the response of patients with major depression to cognitive behavior therapy were complex and that future efforts should aim to maximize sample size and limit subject heterogeneity in order to gain a better understanding of the use of genetic risk factors to predict treatment outcome.

Genetics of Anxiety Disorders

PURPOSE OF REVIEW

Anxiety disorders are among the most common mental disorders with a lifetime prevalence of over 20%. Clinically, anxiety is not thought of as a homogenous disorder, but is subclassified in generalized, panic, and phobic anxiety disorder. Anxiety disorders are moderately heritable. This review will explore recent genetic and epigenetic approaches to anxiety disorders explaining differential susceptibility risk.

RECENT FINDINGS

A substantial portion of the variance in susceptibility risk can be explained by differential inherited and acquired genetic and epigenetic risk. Available data suggest that anxiety disorders are highly complex and polygenic. Despite the substantial progress in genetic research over the last decade, only few risk loci for anxiety disorders have been identified so far. This review will cover recent findings from large-scale genome-wide association studies as well as newer epigenome-wide studies. Progress in this area will likely require analysis of much larger sample sizes than have been reported to date. We discuss prospects for clinical translation of genetic findings and future directions for research.

Internet-delivered psychological treatments: from innovation to implementation

Internet interventions, and in particular Internet-delivered cognitive behaviour therapy (ICBT), have existed for at least 20 years. Here we review the treatment approach and the evidence base, arguing that ICBT can be viewed as a vehicle for innovation. ICBT has been developed and tested for several psychiatric and somatic conditions, and direct comparative studies suggest that therapist-guided ICBT is more effective than a waiting list for anxiety disorders and depression, and tends to be as effective as face-to-face CBT. Studies on the possible harmful effects of ICBT are also reviewed: a significant minority of people do experience negative effects, although rates of deterioration appear similar to those reported for face-to-face treatments and lower than for control conditions. We further review studies on change mechanisms and conclude that few, if any, consistent moderators and mediators of change have been identified. A recent trend to focus on knowledge acquisition is considered, and a discussion on the possibilities and hurdles of implementing ICBT is presented. The latter includes findings suggesting that attitudes toward ICBT may not be as positive as when using modern information technology as an adjunct to face-to-face therapy (i.e., blended treatment). Finally, we discuss future directions, including the role played by technology and machine learning, blended treatment, adaptation of treatment for minorities and non-Western settings, other therapeutic approaches than ICBT (including Internet-delivered psychodynamic and interpersonal psychotherapy as well as acceptance and commitment therapy), emerging regulations, and the importance of reporting failed trials.

Internet interventions: Past, present and future

Internet interventions have been around now for about 20 years. While the field still suffers from a scattered terminology a large number of programs and studies exist. In the present paper I present an overview of my experiences of studying internet-supported cognitive-behaviour therapy (ICBT), but also mention other approaches including the use of smartphones. The paper covers the history of ICBT, short-term effects in controlled trials for a range of conditions, long-term effects, comparisons against face-to-face therapy, effectiveness studies, prediction studies, how the treatment is perceived, critique, and finally future directions. I conclude that we have now reached a stage in which we have numerous evidence-based treatments and procedures, and increasingly internet interventions including ICBT are disseminated.

Imaging and Genetic Approaches to Inform Biomarkers for Anxiety Disorders, Obsessive-Compulsive Disorders, and PSTD

Anxiety disorders are the most common mental health problem in the world and also claim the highest health care cost among various neuropsychiatric disorders. Anxiety disorders have a chronic and recurrent course and cause significantly negative impacts on patients' social, personal, and occupational functioning as well as quality of life. Despite their high prevalence rates, anxiety disorders have often been under-diagnosed or misdiagnosed, and consequently under-treated. Even with the correct diagnosis, anxiety disorders are known to be difficult to treat successfully. In order to implement better strategies in diagnosis, prognosis, treatment decision, and early prevention for anxiety disorders, tremendous efforts have been put into studies using genetic and neuroimaging techniques to advance our understandings of the underlying biological mechanisms. In addition to anxiety disorders including panic disorder, generalised anxiety disorder (GAD), specific phobias, social anxiety disorders (SAD), due to overlapping symptom dimensions, obsessive-compulsive disorder (OCD), and post-traumatic stress disorder (PTSD) (which were removed from the anxiety disorder category in DSM-5 to become separate categories) are also included for review of relevant genetic and neuroimaging findings. Although the number of genetic or neuroimaging studies focusing on anxiety disorders is relatively small compare to other psychiatric disorders such as psychotic disorders or mood disorders, various structural abnormalities in the grey or white matter, functional alterations of activity during resting-state or task conditions, molecular changes of neurotransmitter receptors or transporters, and genetic associations have all been reported. With continuing effort, further genetic and neuroimaging research may potentially lead to clinically useful biomarkers for the prevention, diagnosis, and management of these disorders.

Sleep Treatment Outcome Predictors (STOP) Pilot Study: a protocol for a randomised controlled trial examining predictors of change of insomnia symptoms and associated traits following cognitive-behavioural therapy for insomnia in an unselected sample

INTRODUCTION

Cognitive-behavioural therapy for insomnia (CBT-I) leads to insomnia symptom improvements in a substantial proportion of patients. However, not everyone responds well to this treatment, and it is unclear what determines individual differences in response. The broader aim of this work is to examine to what extent response to CBT-I is due to genetic and environmental factors. The purpose of this pilot study is to examine feasibility of a design to test hypotheses focusing on an unselected sample, that is, without selection on insomnia complaints, in order to plan a larger behavioural genetics study where most participants will likely not have an insomnia disorder.

METHODS AND ANALYSIS

A two parallel-group randomised controlled trial is being conducted across three London universities. Female students (minimum age 18 years) enrolled on a psychology programme at one of the three sites were invited to participate. The target number of participants to be recruited is 240. Following baseline assessments, participants were randomly allocated to either the treatment group, where they received weekly sessions of digital CBT-I for 6 weeks, or the control group, where they completed an online puzzle each week for 6 weeks. Follow-up assessments have taken place mid-intervention (3 weeks) and end of intervention (6 weeks). A 6-month follow-up assessment will also occur. Primary outcomes will be assessed using descriptive statistics and effect size estimates for intervention effects. Secondary outcomes will be analysed using multivariate generalised estimating equation models.

ETHICS AND DISSEMINATION

The study received ethical approval from the Research Ethics and Integrity subcommittee, Goldsmiths, University of London (application reference: EA 1305). DNA sample collection for the BioResource received ethical approval from the NRES Committee South Central-Oxford (reference number: 15/SC/0388). The results of this work shall be published in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT03062891; Results.

Children's differential susceptibility to parenting: An experimental test of "for better and for worse"

Differential susceptibility theory proposes that a subset of individuals exist who display enhanced susceptibility to both negative (risk-promoting) and positive (development-enhancing) environments. This experiment represents the first attempt to directly test this assumption by exposing children in the experimental group to both negative and positive feedback using puppet role-plays. It thereby serves as an empirical test as well as a methodological primer for testing differential susceptibility. Dutch children (N=190, 45.3% girls) between the ages of 4 and 6years participated. We examined whether negative and positive feedback would differentially affect changes in positive and negative affect, in prosocial and antisocial intentions and behavior, depending on children's negative emotionality. Results show that on hearing negative feedback, children in the experimental group increased in negative affect and decreased in positive affect more strongly than children in the control group. On hearing positive feedback, children in the experimental group tended to increase in positive affect and decrease in prosocial behavior. However, changes in response to negative or positive feedback did not depend on children's negative emotionality. Moreover, using reliable change scores, we found support for a subset of "vulnerable" children but not for a subset of "susceptible" children. The findings offer suggestions to guide future differential susceptibility experiments.

Serotonin synthesis rate and the tryptophan hydroxylase-2: G-703T polymorphism in social anxiety disorder

It is disputed whether anxiety disorders, like social anxiety disorder, are characterized by serotonin over- or underactivity. Here, we evaluated whether our recent finding of elevated neural serotonin synthesis rate in patients with social anxiety disorder could be reproduced in a separate cohort, and whether allelic variation in the tryptophan hydroxylase-2 (TPH2) G-703T polymorphism relates to differences in serotonin synthesis assessed with positron emission tomography. Eighteen social anxiety disorder patients and six healthy controls were scanned during 60 minutes in a resting state using positron emission tomography and 5-hydroxy-L-[β -(11)C]tryptophan, [(11)C]5-HTP, a substrate of the second enzymatic step in serotonin synthesis. Parametric images were generated, using the reference Patlak method, and analysed using Statistical Parametric Mapping (SPM8). Blood samples for genotyping of the TPH2 G-703T polymorphism were obtained from 16 social anxiety disorder patients (T carriers: n=5, GG carriers: n=11). A significantly elevated [(11)C]5-HTP accumulation rate, indicative of enhanced decarboxylase activity and thereby serotonin synthesis capacity, was detected in social anxiety disorder patients compared with controls in the hippocampus and basal ganglia nuclei and, at a more lenient (uncorrected) statistical threshold, in the amygdala and anterior cingulate cortex. In patients, the serotonin synthesis rate in the amygdala and anterior cingulate cortex was significantly elevated in TPH2 T carriers in comparison with GG homozygotes. Our results support that social anxiety disorder entails an overactive presynaptic serotonergic system that, in turn, seems functionally influenced by the TPH2 G-703T polymorphism in emotionally relevant brain regions.

Biological markers for anxiety disorders, OCD and PTSD - a consensus statement. Part I: Neuroimaging and genetics

OBJECTIVES

Biomarkers are defined as anatomical, biochemical or physiological traits that are specific to certain disorders or syndromes. The objective of this paper is to summarise the current knowledge of biomarkers for anxiety disorders, obsessive-compulsive disorder (OCD) and post-traumatic stress disorder (PTSD).

METHODS

Findings in biomarker research were reviewed by a task force of international experts in the field, consisting of members of the World Federation of Societies for Biological Psychiatry Task Force on Biological Markers and of the European College of Neuropsychopharmacology Anxiety Disorders Research Network.

RESULTS

The present article (Part I) summarises findings on potential biomarkers in neuroimaging studies, including structural brain morphology, functional magnetic resonance imaging and techniques for measuring metabolic changes, including positron emission tomography and others. Furthermore, this review reports on the clinical and molecular genetic findings of family, twin, linkage, association and genome-wide association studies. Part II of the review focuses on neurochemistry, neurophysiology and neurocognition.

CONCLUSIONS

Although at present, none of the putative biomarkers is sufficient and specific as a diagnostic tool, an abundance of high-quality research has accumulated that will improve our understanding of the neurobiological causes of anxiety disorders, OCD and PTSD.

Biological predictors of pharmacological therapy in anxiety disorders

At least one third of patients with anxiety disorders do not adequately respond to available pharmacological treatment. The reason that some patients with anxiety disorders respond well, but others not, to the same classes of medication is not yet fully understood. It is suggested that several biological factors may influence treatment mechanisms in anxiety and therefore could be identified as possible biomarkers predicting treatment response. In this review, we look at current evidence exploring different types of treatment predictors, including neuroimaging, genetic factors, and blood-related measures, which could open up novel perspectives in clinical management of patients with anxiety disorders.

Genetic differential susceptibility on trial: meta-analytic support from randomized controlled experiments

The most stringent test of differential susceptibility theory is provided by randomized control trials examining the moderating role of genetic markers of differential susceptibility in experimental manipulations of the environment (Gene × Experimental Environment interactions), being at least 10 times more powerful than correlational Gene × Environment interaction studies. We identified 22 experiments involving 3,257 participants with various developmental outcomes (e.g., externalizing problems, internalizing behaviors, and cognitive development). Effect sizes contrasting experimental versus control group were computed both for subjects with the polymorphism considered indicative of heightened susceptibility (e.g., the dopamine receptor D4 gene seven-repeat allele and the serotonin transporter polymorphic region short allele) and others expected to be low in susceptibility (e.g., the dopamine receptor D4 gene four-repeat allele and the serotonin transporter polymorphic region short allele). Clear-cut experimental support for genetic differential susceptibility emerged: the combined effect size of the interventions for the susceptible genotypes amounted to r = .33 (95% confidence interval = 0.23, 0.42; p < .01) versus a nonsignificant r = .08 (95% confidence interval = -0.02, 0.17; p = .12) for the hypothesized nonsusceptible genotypes. Macrotrials showed more evidence of genetic differential susceptibility than microtrials, and differential susceptibility was more clearly observed in trials with externalizing and cognitive outcomes than with internalizing problems. This meta-analysis shows proof of principle for genetic differential susceptibility and indicates that it is time to explore its mechanisms and limits. The concept of differential susceptibility alters the idea of constitutional "risk" factors (reactive temperament and risk genotypes), and points to intervention efficacy hidden in Gene × Environment interactions.

Non-replication of the association between 5HTTLPR and response to psychological therapy for child anxiety disorders

BACKGROUND

We previously reported an association between 5HTTLPR genotype and outcome following cognitive-behavioural therapy (CBT) in child anxiety (Cohort 1). Children homozygous for the low-expression short-allele showed more positive outcomes. Other similar studies have produced mixed results, with most reporting no association between genotype and CBT outcome.

AIMS

To replicate the association between 5HTTLPR and CBT outcome in child anxiety from the Genes for Treatment study (GxT Cohort 2, n = 829).

METHOD

Logistic and linear mixed effects models were used to examine the relationship between 5HTTLPR and CBT outcomes. Mega-analyses using both cohorts were performed.

RESULTS

There was no significant effect of 5HTTLPR on CBT outcomes in Cohort 2. Mega-analyses identified a significant association between 5HTTLPR and remission from all anxiety disorders at follow-up (odds ratio 0.45, P = 0.014), but not primary anxiety disorder outcomes.

CONCLUSIONS

The association between 5HTTLPR genotype and CBT outcome did not replicate. Short-allele homozygotes showed more positive treatment outcomes, but with small, non-significant effects. Future studies would benefit from utilising whole genome approaches and large, homogenous samples.

Internet-Delivered Psychological Treatments

During the past 15 years, much progress has been made in developing and testing Internet-delivered psychological treatments. In particular, therapist-guided Internet treatments have been found to be effective for a wide range of psychiatric and somatic conditions in well over 100 controlled trials. These treatments require (a) a secure web platform, (b) robust assessment procedures, (c) treatment contents that can be text based or offered in other formats, and (d) a therapist role that differs from that in face-to-face therapy. Studies suggest that guided Internet treatments can be as effective as face-to-face treatments, lead to sustained improvements, work in clinically representative conditions, and probably are cost-effective. Despite these research findings, Internet treatment is not yet disseminated in most places, and clinical psychologists should consider using modern information technology and evidence-based treatment programs as a complement to their other services, even though there will always be clients for whom face-to-face treatment is the best option.

Catehol-o-methyltransferase gene Val158met polymorphism as a potential predictor of response to computer-assisted delivery of cognitive-behavioral therapy among cocaine-dependent individuals: Preliminary findings from a randomized controlled trial

BACKGROUND

Findings from uncontrolled studies suggest that the COMT Val108/158Met polymorphism may affect response to cognitive behavioral therapy (CBT) in some populations. Using data from a randomized controlled trial evaluating computerized CBT (CBT4CBT), we evaluated treatment response by COMT genotype, with the a priori hypothesis that Val carriers would have improved response to computerized delivery of CBT.

METHODS

101 cocaine-dependent individuals, of whom 81 contributed analyzable genetic samples, were randomized to standard methadone maintenance treatment plus CBT4CBT or standard treatment alone in an 8 week trial.

RESULTS

There was a significant genotype by time effect on frequency of cocaine use from baseline to the end of the 6 month follow-up, suggesting greater reductions over time for Val carriers relative to individuals with the Met/Met genotype. There was a significant treatment condition by genotype interactions for rates of participants attaining 21 or more days of continuous abstinence as well as self-reported percent days of abstinence, suggesting less cocaine use among Val carriers when assigned to CBT compared to standard treatment. Exploration of possible mechanisms using measures of attentional biased also pointed to greater change over time in these measures among the Val carriers assigned to CBT.

CONCLUSION

These are the first data from a randomized controlled trial indicating significant interactions of COMT polymorphism and behavioral therapy condition on treatment outcome, where Val carriers appeared to respond particularly well to computerized CBT. These preliminary data point to a potential biomarker of response to CBT linked to its putative mechanism of action, enhanced cognitive control.

Neurocognitive outcomes in long-term survivors of childhood acute lymphoblastic leukemia treated on contemporary treatment protocols: A systematic review

The intensified administration of chemotherapeutic drugs has gradually replaced cranial radiation therapy (CRT) for the treatment of childhood acute lymphoblastic leukemia (ALL). While CRT is often implicated in neurocognitive impairment in ALL survivors, there is a paucity of the literature that evaluates the persistence of neurocognitive deficits in long-term survivors of pediatric ALL who were treated with contemporary chemotherapy-only protocols. Results from this systematic review concurred to the probable cognitive-sparing effect of chemotherapy-based protocols over CRT in long-term survivors. However, coupled with multiple intrinsic and extrinsic factors, survivors who received chemotherapy treatment still suffered from apparent cognitive impairment, particularly in the attention and executive function domains. Notably, there is evidence to suggest that the late neurotoxic effect of methotrexate on survivors' neurocognitive performance may be dose-related. This review also recommends future pharmacokinetic, neuroimaging and genetic studies to illuminate the multifactorial nature of this subject matter and discusses the potential value of neurochemical, physiological, inflammatory and genetic markers for the prediction of susceptibility to neurocognitive impairment in long-term survivors of childhood ALL.

The hidden efficacy of interventions: gene×environment experiments from a differential susceptibility perspective

The efficacy of interventions might be underestimated or even go undetected as a main effect when it is hidden in gene-by-environment (G×E) interactions. This review moves beyond the problems thwarting correlational G×E research to propose genetic differential susceptibility experiments. G×E experiments can test the bright side as well as the dark side of the moderating role of genotypes traditionally considered to represent vulnerability to negative conditions. The differential susceptibility model predicts that carriers of these risk genotypes profit most from interventions changing the environment for the better. The evolutionary background of G×E and differential susceptibility is discussed, and statistical methods for the analysis of differential susceptibility (versus diathesis stress) are reviewed. Then, based on results from 22 randomized G×E experiments, meta-analytic evidence for the differential susceptibility model is presented. Intervention effects are much stronger in the susceptible genotypes than in the nonsusceptible genotypes. The final sections suggest possibilities to broaden the G component in the G×E equation by including genetic pathways, and to broaden the E component by including methylation level and gene expression as promising ways to probe the concept of the environment more deeply and address the perennial issue of what works for whom.