How side effects can improve treatment efficacy: a randomized trial.

While treatment side effects may adversely impact patients, they could also potentially function as indicators for effective treatment. In this study, we investigated whether and how side effects can trigger positive treatment expectations and enhance treatment outcomes. In this pre-registered trial (DRKS00026648), 77 healthy participants were made to believe that they will receive fentanyl nasal sprays before receiving thermal pain in a controlled experimental setting. However, nasal sprays did not contain fentanyl, rather they either contained capsaicin to induce a side effect (mild burning sensation) or saline (inert). After the first session, participants were randomized to two groups and underwent functional MRI. One group continued to believe that the nasal sprays could contain fentanyl while the other group was explicitly informed that no fentanyl was included. This allowed for the independent manipulation of the side effects and the expectation of pain relief. Our results revealed that nasal sprays with a side effect lead to lower pain than inert nasal sprays without side effects. The influence of side effects on pain was dependent on individual beliefs about how side effects are related to treatment outcome, as well as on expectations about received treatment. Functional MRI data indicated an involvement of the descending pain modulatory system including the anterior cingulate cortex and the periaqueductal gray during pain after experiencing a nasal spray with side effects. In summary, our data show that mild side effects can serve as a signal for effective treatment thereby influencing treatment expectations and outcomes, which is mediated by the descending pain modulatory system. Using these mechanisms in clinical practice could provide an efficient way to optimize treatment outcome. In addition, our results indicate an important confound in clinical trials, where a treatment (with potential side effects) is compared to placebo.

Study protocol: combined N-of-1 trials to assess open-label placebo treatment for antidepressant discontinuation symptoms [FAB-study].

BACKGROUND: Antidepressant discontinuation is associated with a broad range of adverse effects. Debilitating discontinuation symptoms can impede the discontinuation process and contribute to unnecessary long-term use of antidepressants. Antidepressant trials reveal large placebo effects, indicating a potential use of open-label placebo (OLP) treatment to facilitate the discontinuation process. We aim to determine the effect of OLP treatment in reducing antidepressant discontinuation symptoms using a series of N-of-1 trials. METHODS: A series of randomized, single-blinded N-of-1 trials will be conducted in 20 patients with fully remitted DSM-V major depressive disorder, experiencing moderate to severe discontinuation symptoms following antidepressant discontinuation. Each N-of-1 trial consists of two cycles, each comprising two-week alternating periods of OLP treatment and of no treatment in a random order, for a total of eight weeks. Our primary outcome will be self-reported discontinuation symptoms rated twice daily via the smartphone application 'StudyU'. Secondary outcomes include expectations about discontinuation symptoms and (depressed) mood. Statistical analyses will be based on a Bayesian multi-level random effects model, reporting posterior estimates of the overall and individual treatment effects. DISCUSSION: Results of this trial will provide insight into the clinical application of OLP in treating antidepressant discontinuation symptoms, potentially offering a new cost-effective therapeutic tool. This trial will also determine the feasibility and applicability of a series of N-of-1 trials in a clinical discontinuation trial. TRIAL REGISTRATION: ClinicalTrials.gov: NCT05051995, first registered September 20, 2021.

Disentangling pharmacological and expectation effects in antidepressant discontinuation among patients with fully remitted major depressive disorder: study protocol of a randomized, open-hidden discontinuation trial.

BACKGROUND: Antidepressants are established as an evidence-based, guideline-recommended treatment for Major Depressive Disorder. Prescriptions have markedly increased in past decades, with a specific surge in maintenance prescribing. Patients often remain on antidepressants longer than clinically necessary. When attempting to stop, many patients experience adverse discontinuation symptoms. Discontinuation symptoms can be debilitating and hinder successful discontinuation. While discontinuation symptoms can result from pharmacological effects, evidence on nocebo-induced side effects of antidepressant use suggests that patients' expectations may also influence occurrence. METHODS: To disentangle pharmacological and expectation effects in antidepressant discontinuation, patients with fully remitted Major Depressive Disorder who fulfill German guideline recommendations to discontinue will either remain on or discontinue their antidepressant. Participants' expectations will be manipulated by varying verbal instructions using an open-hidden paradigm. Within the open trial arms, participants will receive full information about treatment, i.e., high expectation. Within the hidden trial arms, participants will be informed about a 50% chance of discontinuing versus remaining on their antidepressant, i.e., moderate expectation. A total of N = 196 participants will be randomly assigned to either of the four experimental groups: open discontinuation (OD; n = 49), hidden discontinuation (HD; n = 49), open continuation (OC; n = 49), or hidden continuation (HC; n = 49). Discontinuation symptom load during the 13-week experimental phase will be our primary outcome measure. Secondary outcome measures include discontinuation symptom load during the subsequent 39-week clinical observation phase, recurrence during the 13-week experimental period, recurrence over the course of the complete 52-week trial evaluated in a time-to-event analysis, and stress, anxiety, and participants' attentional and emotional processing at 13 weeks post-baseline. Blood and saliva samples will be taken as objective markers of antidepressant blood serum level and stress. Optional rsfMRI measurements will be scheduled. DISCUSSION: Until today, no study has explored the interplay of pharmacological effects and patients' expectations during antidepressant discontinuation. Disentangling their effects has important implications for understanding mechanisms underlying adverse discontinuation symptoms. Results can inform strategies to manage discontinuation symptoms and optimize expectations in order to help patients and physicians discontinue antidepressants more safely and effectively. TRIAL REGISTRATION: ClinicalTrials.gov (NCT05191277), January 13, 2022.

Distinct brain structure and behavior related to ADHD and conduct disorder traits.

Attention-Deficit/Hyperactivity Disorder (ADHD) and conduct disorder (CD) exemplify top-down dysregulation conditions that show a large comorbidity and shared genetics. At the same time, they entail two different types of symptomology involving mainly non-emotional or emotional dysregulation. Few studies have tried to separate the specific biology underlying these two dimensions. It has also been suggested that both types of conditions consist of extreme cases in the general population where the symptoms are widely distributed. Here we test whether brain structure is specifically associated to ADHD or CD symptoms in a general population of adolescents (n = 1093) being part of the IMAGEN project. Both ADHD symptoms and CD symptoms were related to similar and overlapping MRI findings of a smaller structure in prefrontal and anterior cingulate cortex. However, our regions of interest (ROI) approach indicated that gray matter volume (GMV) and surface area (SA) in dorsolateral/dorsomedial prefrontal cortex and caudal anterior cingulate cortex were negatively associated to ADHD symptoms when controlling for CD symptoms while rostral anterior cingulate cortex GMV was negatively associated to CD symptoms when controlling for ADHD symptoms. The structural findings were mirrored in performance of neuropsychological tests dependent on prefrontal and anterior cingulate regions, showing that while performance on the Stop Signal test was specifically related to the ADHD trait, delayed discounting and working memory were related to both ADHD and CD traits. These results point towards a partially domain specific and dimensional capacity in different top-down regulatory systems associated with ADHD and CD symptoms.

Heavy drinking in adolescents is associated with change in brainstem microstructure and reward sensitivity.

Heavy drinker adolescents: altered brainstem microstructure.

The cortical-cerebellar circuit is vulnerable to heavy drinking (HD) in adults. We hypothesized early microstructural modifications of the pons/midbrain region, containing core structures of the reward system, in HD adolescents. Thirty-two otherwise symptom-free HDs at age 14 (HD14) and 24 abstainers becoming HDs at age 16 (HD16) were identified in the community with the Alcohol Use Disorders Identification Test (AUDIT) and compared with abstainers. The monetary incentive delay (MID) task assessed reward-sensitive performance. Voxelwise statistics of diffusion tensor imaging (DTI) values in the thalamo-ponto-mesencephalic region were obtained using tract-based spatial statistics. Projections between the ventral tegmental area (VTA) and the nucleus accumbens (NAcc) were identified by probabilistic tractography. Lower fraction of anisotropy and higher radial diffusivity (RD) values were detected in the upper dorsal pons of HD14 adolescents, and a trend for higher RD in HD16, compared with abstainers. When expecting reward, HD14 had higher MID task success scores than abstainers, and success scores were higher with a lower number of tracts in all adolescents. In symptom-free community adolescents, a region of lower white matter (WM) integrity in the pons at age 14 was associated with current HD and predicted HD at age 16. HD was related to reward sensitivity.

Dopaminergic receptor blockade changes a functional connectivity network centred on the amygdala.

Resting-state connectivity has become an increasingly important measure in characterizing the functional integrity of brain circuits in neuro-psychiatric conditions. One approach that has recently gained prominence in this regard-and which we use in this study-is to investigate how resting-state connectivity depends on the integrity of certain neuromodulator systems. Here, we use a pharmacological challenge in combination with functional magnetic resonance imaging to investigate the impact of dopaminergic receptor blockade on whole brain functional connectivity in twenty healthy human subjects. Administration of the D2-receptor antagonist haloperidol led to a profound change in functional integration in network nodes linked to the amygdala. Compared to placebo and baseline measurements, network-based statistics and pairwise connectivity analyses revealed reduced connectivity and decreased link strength between the amygdala and the bilateral posterior cingulate cortex and other cortical areas. This was complemented by less extensive but very circumscribed enhanced connectivity between the amygdala and the right putamen during D2-receptor blockade. It will be interesting to investigate whether these pharmacologically induced shifts in resting-state connectivity will similarly be evident in clinical conditions that involve a dysfunction of the dopaminergic system. Our findings might also aid in interpreting alterations in more complex states, such as those seen psychiatric conditions and their treatment. Hum Brain Mapp 37:4148-4157, 2016. © 2016 Wiley Periodicals, Inc.

Nicotine reduces discrimination between threat and safety in the hippocampus, nucleus accumbens and amygdala.

Nicotine intake is linked to the maintenance and development of anxiety disorders and impairs adaptive discrimination of threat and safety in rodents and humans. Yet, it is unclear if nicotine exerts a causal pharmacological effect on the affective and neural mechanisms that underlie aversive learning. We conducted a pre-registered, pseudo-randomly and double-blinded pharmacological fMRI study to investigate the effect of acute nicotine on Fear Acquisition and Extinction in non-smokers (n = 88). Our results show that nicotine administration led to decreased discrimination between threat and safety in subjective fear. Nicotine furthermore decreased differential (threat vs. safety) activation in the hippocampus, which was functionally coupled with Nucleus Accumbens and amygdala, compared to placebo controls. Additionally, nicotine led to enhanced physiological arousal to learned threats and overactivation of the ventral tegmental area. This study provides mechanistic evidence that single doses of nicotine impair neural substrates of adaptive aversive learning in line with the risk for the development of pathological anxiety.

Extending the Construct Network of Trait Disinhibition to the Neuroimaging Domain: Validation of a Bridging Scale for Use in the European IMAGEN Project.

Trait disinhibition, a clinical-liability construct, has well-established correlates in the diagnostic, self-rating, task-behavioral, and brain potential response domains. Recently, studies have begun to test for neuroimaging correlates of this liability factor, but more work of this type using larger data sets is needed to clarify its brain bases. The current study details the development and validation of a scale measure of trait disinhibition composed of questionnaire items available in the IMAGEN project, a large-scale longitudinal study of factors contributing to substance abuse that includes clinical interview, self-report personality, task-behavioral, neuroimaging, and genomic measures. Using a construct-rating and psychometric refinement approach, a scale was developed that evidenced: (a) positive relations with interview-assessed psychopathology in the IMAGEN sample, both concurrently and prospectively and (b) positive associations with scale measures of disinhibition and reported psychopathology, and a robust negative correlation with P3 brain response, in a separate adult sample ( Mage = 19.5). These findings demonstrate that a common scale measure can index this construct from adolescence through to early adulthood, and set the stage for systematic work directed at identifying neural and genetic biomarkers of this key liability construct using existing and future data from the IMAGEN project.

Pubertal maturation and sex effects on the default-mode network connectivity implicated in mood dysregulation.

This study examines the effects of puberty and sex on the intrinsic functional connectivity (iFC) of brain networks, with a focus on the default-mode network (DMN). Consistently implicated in depressive disorders, the DMN's function may interact with puberty and sex in the development of these disorders, whose onsets peak in adolescence, and which show strong sex disproportionality (females > males). The main question concerns how the DMN evolves with puberty as a function of sex. These effects are expected to involve within- and between-network iFC, particularly, the salience and the central-executive networks, consistent with the Triple-Network Model. Resting-state scans of an adolescent community sample (n = 304, male/female: 157/147; mean/std age: 14.6/0.41 years), from the IMAGEN database, were analyzed using the AFNI software suite and a data reduction strategy for the effects of puberty and sex. Three midline regions (medial prefrontal, pregenual anterior cingulate, and posterior cingulate), within the DMN and consistently implicated in mood disorders, were selected as seeds. Within- and between-network clusters of the DMN iFC changed with pubertal maturation differently in boys and girls (puberty-X-sex). Specifically, pubertal maturation predicted weaker iFC in girls and stronger iFC in boys. Finally, iFC was stronger in boys than girls independently of puberty. Brain-behavior associations indicated that lower connectivity of the anterior cingulate seed predicted higher internalizing symptoms at 2-year follow-up. In conclusion, weaker iFC of the anterior DMN may signal disconnections among circuits supporting mood regulation, conferring risk for internalizing disorders.

Identification of neurobehavioural symptom groups based on shared brain mechanisms.

Most psychopathological disorders develop in adolescence. The biological basis for this development is poorly understood. To enhance diagnostic characterization and develop improved targeted interventions, it is critical to identify behavioural symptom groups that share neural substrates. We ran analyses to find relationships between behavioural symptoms and neuroimaging measures of brain structure and function in adolescence. We found two symptom groups, consisting of anxiety/depression and executive dysfunction symptoms, respectively, that correlated with distinct sets of brain regions and inter-regional connections, measured by structural and functional neuroimaging modalities. We found that the neural correlates of these symptom groups were present before behavioural symptoms had developed. These neural correlates showed case-control differences in corresponding psychiatric disorders, depression and attention deficit hyperactivity disorder in independent clinical samples. By characterizing behavioural symptom groups based on shared neural mechanisms, our results provide a framework for developing a classification system for psychiatric illness that is based on quantitative neurobehavioural measures.

Early Variations in White Matter Microstructure and Depression Outcome in Adolescents With Subthreshold Depression.

OBJECTIVE: White matter microstructure alterations have recently been associated with depressive episodes during adolescence, but it is unknown whether they predate depression. The authors investigated whether subthreshold depression in adolescence is associated with white matter microstructure variations and whether they relate to depression outcome. METHOD: Adolescents with subthreshold depression (N=96) and healthy control subjects (N=336) drawn from a community-based cohort were compared using diffusion tensor imaging and whole brain tract-based spatial statistics (TBSS) at age 14 to assess white matter microstructure. They were followed up at age 16 to assess depression. Probabilistic tractography was used to reconstruct white matter streamlines spreading from the regions identified in the TBSS analysis and along bundles implicated in emotion regulation, the uncinate fasciculus and the cingulum. The authors searched for mediating effects of white matter microstructure on the relationship between baseline subthreshold depression and depression at follow-up, and then explored the specificity of the findings. RESULTS: Lower fractional anisotropy (FA) and higher radial diffusivity were found in the anterior corpus callosum in the adolescents with subthreshold depression. Tractography analysis showed that they also had lower FA in the right cingulum streamlines, along with lower FA and higher mean diffusivity in tracts connecting the corpus callosum to the anterior cingulate cortex. The relation between subthreshold depression at baseline and depression at follow-up was mediated by FA values in the latter tracts, and lower FA values in those tracts distinctively predicted higher individual risk for depression. CONCLUSIONS: Early FA variations in tracts projecting from the corpus callosum to the anterior cingulate cortex may denote a higher risk of transition to depression in adolescents.

Preserved Capacity for Placebo Analgesia in the Elderly.

The prevalence of chronic pain rises with increasing age. It has been suggested that the mechanisms responsible for the development of chronic pain overlap with mechanisms involved in aging, potentially implicating age-related changes in descending modulatory pathways. This observation raises the question whether other forms of endogenous pain modulation, in particular placebo analgesia, become compromised with age. Because of the known contribution of placebo effects to analgesic treatment outcomes this question is of important clinical relevance. In this study, we compared the response to thermal painful stimuli and the capacity for endogenous pain modulation between younger and older adults using a well established placebo analgesia paradigm involving expectancy and conditioning components. We recruited 30 younger (age 23-40 years, mean = 27.04, standard error of the mean ± .61) and 24 older adults (60-80 years, mean = 69.3, standard error of the mean ± .89). We observed increased heat pain thresholds and higher pain intensity ratings (in response to physically identical heat stimulation) in the older compared with the younger group. However, the placebo analgesic response was comparable between both age groups of healthy participants. The preserved capacity for placebo analgesia in our sample of older participants highlights the potential to use nonpharmacological analgesic treatment strategies in this age group and to exploit placebo mechanisms as an add-on to existing analgesic (pharmacological) treatment strategies. PERSPECTIVE: In contrast to the commonly shared view that endogenous pain modulation declines with age we found a comparable capacity for placebo analgesia in a group of healthy older and younger adults.

Neural correlates of three types of negative life events during angry face processing in adolescents.

Negative life events (NLE) contribute to anxiety and depression disorders, but their relationship with brain functioning in adolescence has rarely been studied. We hypothesized that neural response to social threat would relate to NLE in the frontal-limbic emotional regions. Participants (N = 685) were drawn from the Imagen database of 14-year-old community adolescents recruited in schools. They underwent functional MRI while viewing angry and neutral faces, as a probe to neural response to social threat. Lifetime NLEs were assessed using the 'distress', 'family' and 'accident' subscales from a life event dimensional questionnaire. Relationships between NLE subscale scores and neural response were investigated. Links of NLE subscales scores with anxiety or depression outcomes at the age of 16 years were also investigated. Lifetime 'distress' positively correlated with ventral-lateral orbitofrontal and temporal cortex activations during angry face processing. 'Distress' scores correlated with the probabilities of meeting criteria for Generalized Anxiety Disorder or Major Depressive Disorder at the age of 16 years. Lifetime 'family' and 'accident' scores did not relate with neural response or follow-up conditions, however. Thus, different types of NLEs differentially predicted neural responses to threat during adolescence, and differentially predicted a de novo internalizing condition 2 years later. The deleterious effect of self-referential NLEs is suggested.

Are Children the Better Placebo Analgesia Responders? An Experimental Approach.

UNLABELLED: There is little information regarding changes in placebo responsiveness with age, although first predictors of placebo responders such as psychological and physiological processes have been identified. Reviews and meta-analyses indicate that placebo response rates in randomized controlled trials (RCTs) are higher in children and adolescents compared with adults. As these studies cannot control for age-dependent differences in the natural course of the disease, biases might contribute to different placebo rates in RCTs. To avoid these biases, this study investigated age-related differences in placebo responsiveness between children and adults in a well-established experimental model of placebo analgesia combining classic conditioning and expectation. Our data confirm placebo analgesic responses in children, which did not differ in magnitude from those of adults. The influence of previous experience on subsequent treatment outcome was stronger in children than in adults, indicating an increased relevance of learning processes for treatment outcomes in children. Further studies are needed to understand the influence of treatment-related learning processes in children and adolescents, which might critically determine treatment responsiveness during adulthood. PERSPECTIVE: This study is the first to experimentally explore placebo analgesia and influences of previous experience on placebo responses in children compared with adults. We found comparable placebo responses in both groups and an increased relevance of learning processes for treatment outcomes in children.

Subthreshold depression and regional brain volumes in young community adolescents.

OBJECTIVE: Neuroimaging findings have been reported in regions of the brain associated with emotion in both adults and adolescents with depression, but few studies have investigated whether such brain alterations can be detected in adolescents with subthreshold depression, a condition at risk for major depressive disorder. In this study, we searched for differences in brain structure at age 14 years in adolescents with subthreshold depression and their relation to depression at age 16 years. METHOD: High-resolution structural magnetic resonance imaging was used to assess adolescents with self-reported subthreshold depression (n = 119) and healthy control adolescents (n = 461), all recruited from a community-based sample. Regional gray and white matter volumes were compared across groups using whole-brain voxel-based morphometry. The relationship between subthreshold depression at baseline and depression outcome was explored using causal mediation analyses to search for mediating effects of regional brain volumes. RESULTS: Adolescents with subthreshold depression had smaller gray matter volume in the ventromedial prefrontal and rostral anterior cingulate cortices and caudates, and smaller white matter volumes in the anterior limb of internal capsules, left forceps minor, and right cingulum. In girls, but not in boys, the relation between subthreshold depression at baseline and high depression score at follow-up was mediated by medial-prefrontal gray matter volume. CONCLUSION: Subthreshold depression in early adolescence might be associated with smaller gray and white matter volumes in regions of the frontal-striatal-limbic affective circuit, and the occurrence of depression in girls with subthreshold depression might be influenced by medial-prefrontal gray matter volume. However, these findings should be interpreted with caution because of the limitations of the clinical assessment methods.

The Brain's Response to Reward Anticipation and Depression in Adolescence: Dimensionality, Specificity, and Longitudinal Predictions in a Community-Based Sample.

OBJECTIVE: The authors examined whether alterations in the brain's reward network operate as a mechanism across the spectrum of risk for depression. They then tested whether these alterations are specific to anhedonia as compared with low mood and whether they are predictive of depressive outcomes. METHOD: Functional MRI was used to collect blood-oxygen-level-dependent (BOLD) responses to anticipation of reward in the monetary incentive task in 1,576 adolescents in a community-based sample. Adolescents with current subthreshold depression and clinical depression were compared with matched healthy subjects. In addition, BOLD responses were compared across adolescents with anhedonia, low mood, or both symptoms, cross-sectionally and longitudinally. RESULTS: Activity in the ventral striatum was reduced in participants with subthreshold and clinical depression relative to healthy comparison subjects. Low ventral striatum activation predicted transition to subthreshold or clinical depression in previously healthy adolescents at 2-year follow-up. Brain responses during reward anticipation decreased in a graded manner between healthy adolescents, adolescents with current or future subthreshold depression, and adolescents with current or future clinical depression. Low ventral striatum activity was associated with anhedonia but not low mood; however, the combined presence of both symptoms showed the strongest reductions in the ventral striatum in all analyses. CONCLUSIONS: The findings suggest that reduced striatal activation operates as a mechanism across the risk spectrum for depression. It is associated with anhedonia in healthy adolescents and is a behavioral indicator of positive valence systems, consistent with predictions based on the Research Domain Criteria.

No evidence for enhanced extinction memory consolidation through noradrenergic reuptake inhibition-delayed memory test and reinstatement in human fMRI.

RATIONALE: One promising approach in the current ambition to maximise treatment benefit for anxiety disorders is the pharmacological enhancement of cognitive-behavioural treatment efficacy, which can be experimentally modelled by pharmacological enhancement of extinction learning/consolidation. Noradrenaline (NA) is involved in memory consolidation, and NAergic innervations are found in brain areas implicated in fear conditioning and extinction. OBJECTIVES: Thus, to enhance extinction memory consolidation through boosted NAergic signalling, we administered 4 mg reboxetine (RBX) immediately after extinction learning (day 2, 24 h after conditioning on day 1) in a randomised, placebo (PLC)-controlled design. At a delayed memory test (day 8), we probed cued and contextual fear and extinction memories before and after a reinstatement manipulation. RESULTS: After reinstatement, we find significantly enhanced amygdala and posterior hippocampus activation in the RBX group, areas implicated in fear memory expression, while the PLC group exhibited enhanced activation in areas associated with extinction memory expression (vmPFC, anterior hippocampus). No group differences were found in skin conductance responses. CONCLUSIONS: Thus, our data do not support our hypothesis that enhancement of NA signalling may facilitate extinction memory consolidation and provide preliminary evidence that this might rather enhance fear memories on a neural but not physiological (skin conductance responses) level.