The effects of acute tryptophan depletion on instrumental reward learning in anorexia nervosa - an fMRI study.

BACKGROUND: The serotonin (5-HT) hypothesis of anorexia nervosa (AN) posits that individuals predisposed toward or recovered from AN (recAN) have a central nervous hyperserotonergic state and therefore restrict food intake as a means to reduce 5-HT availability (via diminished tryptophan-derived precursor supply) and alleviate associated negative mood states. Importantly, the 5-HT system has also been generally implicated in reward processing, which has also been shown to be altered in AN. METHODS: In this double-blind crossover study, 22 individuals recAN and 25 healthy control participants (HC) underwent functional magnetic resonance imaging (fMRI) while performing an established instrumental reward learning paradigm during acute tryptophan depletion (ATD; a dietary intervention that lowers central nervous 5-HT availability) as well as a sham depletion. RESULTS: On a behavioral level, the main effects of reward and ATD were evident, but no group differences were found. fMRI analyses revealed a group × ATD × reward level interaction in the ventral anterior insula during reward anticipation as well as in the medial orbitofrontal cortex during reward consumption. DISCUSSION: The precise pattern of results is suggestive of a 'normalization' of reward-related neural responses during ATD in recAN compared to HC. Our results lend further evidence to the 5-HT hypothesis of AN. Decreasing central nervous 5-HT synthesis and availability during ATD and possibly also by dieting may be a means to normalize 5-HT availability and associated brain processes.

Acute tryptophan depletion balances altered resting-state functional connectivity of the salience network in female patients recovered from anorexia nervosa.

BACKGROUND: It has been suggested that individuals predisposed to or recovered from anorexia nervosa experience a hyperserotonergic state associated with anxiety that might be mitigated by restricted food intake, because diminished levels of the tryptophan precursor lower the central availability of serotonin (5-HT). At the neural level, the salience network is a system of functionally connected brain regions; it has been closely associated with 5-HT functioning and mental disorders (including anorexia nervosa). The aim of the present study was to investigate the effect on the salience network of a temporary dietary manipulation of 5-HT synthesis in patients with anorexia nervosa. METHODS: In this double-blind crossover study, we obtained data on resting-state functional connectivity from 22 weight-recovered female patients with a history of anorexia nervosa, and 22 age-matched female healthy controls. The study procedure included acute tryptophan depletion (a dietary intervention that lowers the central 5-HT synthesis rate) and a sham condition. RESULTS: We identified an interaction of group and experimental condition in resting-state functional connectivity between the salience network and the orbitofrontal cortex extending to the frontal pole (F 1,42 = 12.52; p FWE = 0.026). Further analysis revealed increased resting-state functional connectivity during acute tryptophan depletion in patients recovered from anorexia nervosa, resembling that of healthy controls during the sham condition (T 42 = -0.66; p = 0.51). LIMITATIONS: The effect of acute tryptophan depletion on the central availability of 5-HT can be judged only indirectly using plasma ratios of tryptophan to large neutral amino acids. Moreover, the definition of anorexia nervosa recovery varies widely across studies, limiting comparability. CONCLUSION: Taken together, our findings support the notion of 5-HT dysregulation in anorexia nervosa and indicate that reduced 5-HT synthesis and availability during acute tryptophan depletion (and possibly with food restriction) may balance hyperserotonergic functioning and the associated resting-state functional connectivity of the salience network.

Integrity of Amygdala Subregion-Based Functional Networks and Emotional Lability in Drug-Naïve Boys With ADHD.

Objective: This study evaluated the functional networks of amygdala subregions (basolateral [BLA], centromedial [CMA], and superficial amygdala [SFA]) in ADHD and their association with emotional lability (EL) symptoms. Method: Resting-state functional connectivity (RSFC) of amygdala subregions and their correlations with EL scores were evaluated in 35 drug-naïve boys with ADHD and 30 age-matched healthy controls (HC). Results: Compared with HC, altered RSFC were detected differently for each amygdala subregion in ADHD: altered RSFC of BLA with the thalamus and vermis; aberrant RSFC of CMA with the superior temporal gyrus/pole and insula, precuneus and cerebellum; reduced RSFC of SFA with dorsal frontoparietal cortices. Within ADHD, higher EL scores were associated with reduced negative RSFC of SFA with the dorsolateral prefrontal cortex and inferior parietal lobe. Conclusion: Diffuse alterations of amygdala subregion-based networks are associated with ADHD, and the weaker SFA-frontoparietal networks might be involved in the hypothesized top-down effortful regulation of emotion.

Gender-affirming hormones and surgery in transgender children and adolescents.

The Endocrine Society Clinical Practice Guidelines on the treatment of gender incongruent people recommend the use of gender-affirming cross-sex hormone (CSH) interventions in transgender children and adolescents who request this treatment, who have undergone psychiatric assessment, and have maintained a persistent transgender identity. The intervention can help to affirm gender identity by inducing masculine or feminine physical characteristics that are congruent with an individual's gender expression, while aiming to improve mental health and quality-of-life outcomes. Some transgender individuals might also wish to access gender-affirming surgeries during adolescence; however, research to inform best clinical practice for surgeons and other medical professionals is scarce. This Review explores the available published evidence on gender-affirming CSH and surgical interventions in transgender children and adolescents, amalgamating findings on mental health outcomes, cognitive and physical effects, side-effects, and safety variables. The small amount of available data suggest that when clearly indicated in accordance with international guidelines, gender-affirming CSHs and chest wall masculinisation in transgender males are associated with improvements in mental health and quality of life. Evidence regarding surgical vaginoplasty in transgender females younger than age 18 years remains extremely scarce and conclusions cannot yet be drawn regarding its risks and benefits in this age group. Further research on an international scale is urgently warranted to clarify long-term outcomes on psychological functioning and safety.

Nitrous oxide (N2O) and subsequent open-label SSRI treatment of adolescents with depression (NOTAD): study protocol for a randomised controlled trial.

BACKGROUND: The first line of pharmacological treatment for severe depressive disorders in young people is selective serotonin reuptake inhibitors (SSRIs). However, beneficial clinical effects are rarely observed before several weeks into treatment. Nitrous oxide (N2O) has a long-standing safety record for pain relief and has been used in adults and young people. In adults with severe treatment-resistant depression, a single dose of N2O had significant antidepressant effects, with maximum antidepressant effects observed 24 h after administration. However, the antidepressant effects of N2O have never been investigated in adolescents with a confirmed diagnosis of depression in a prospective trial. The aims of this study are to (1) investigate whether a single inhaled N2O administration leads to antidepressant effects in adolescents with depression at 24 h, (2) determine whether combined N2O and SSRI administration (commenced after N2O intervention) provides a clinically significant improvement in mood over and above the benefits from SSRI administration alone, and, (3) investigate whether the effect seen following N2O administration can be used as a predictor of SSRI treatment response. METHODS/DESIGN: In this study, we will use a single-blind, randomised, placebo-controlled design. Patients aged between 12 and 17 years with major depressive disorder will be recruited. This study will consist of two phases: phase A and phase B. During phase A, participants will be randomised to receive either inhaled N2O or placebo (air) for 1 h. In phase B, participants will receive open-label pharmacological treatment with the SSRI fluoxetine and will be followed over a 12-week period. Participants will undertake mood assessments at 2 and 24 h after N2O or placebo administration (phase A) and weekly during the 12-week follow up in phase B. DISCUSSION: We expect an antidepressant effect from a single dose of inhaled N2O compared with placebo at 24 h after administration. Additionally, we expect that subjects treated with N2O will also show greater improvements than the placebo group after 6 and 12 weeks into fluoxetine treatment because of potential additive antidepressant effects. Such findings would be of clinical importance because currently children and adolescents often do not experience any symptom alleviation for several weeks following the initiation of SSRIs. TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Registry, ACTRN12616001568404 . Registered on 14 November 2016.

Dietary tryptophan depletion in humans using a simplified two amino acid formula - a pilot study.

BACKGROUND: Acute tryptophan depletion (ATD) is a well-established dietary method in translational brain research used to briefly lower central nervous serotonin (5-hydroxytryptamine (5-HT)) synthesis. A simplified two amino acid ATD formula (ATDPHE/LEU) was developed while reducing the overall amount of amino acids (AAs), with the objective of administration especially in children and adolescents in future studies. OBJECTIVE: This study investigated tryptophan (TRP) influx rates across the blood-brain barrier (BBB) after dietary ATDPHE/LEU administration relative to the ATD Moja-De protocol that has been established for use in children and adolescents. DESIGN: Seventy-two healthy adults (50% females) were randomized into four groups and administered ATD Moja-De, its TRP-balanced control condition (BAL), ATDPHE/LEU, or its respective control mixture (BALPHE/LEU) in a counterbalanced, double-blind, between-subjects design. Blood samples were collected at baseline and at hourly intervals for 6 h after AA intake. Questionnaires about mood, taste, and challenge tolerance were completed at fixed time points. RESULTS: Both challenge mixtures significantly reduced central nervous TRP influx as calculated by Michaelis-Menten kinetics relative to baseline and the respective control conditions with only mild and comparable side effects. A greater decline in TRP influx over the BBB after ATDPHE/LEU administration when compared with ATD Moja-De was detected without group effects for taste, challenge tolerance, and mood. There was unintended initial short increase in plasma TRP concentrations observed after ATDPHE/LEU intake, and a possible redistribution between free and protein-bound TRP triggered by protein synthesis stimulated by the ingested AAs may account for this finding. Moreover, a decline in TRP influx after BALPHE/LEU administration over a 6-h period was observed, and the large amount of PHE in the BALPHE/LEU mixture may be a possible explanation for this particular phenomenon, which could have led to an unexpected increase in displacement of TRP at the BBB in this control condition. CONCLUSIONS: This pilot study provides preliminary evidence for the possibility of lowering TRP influx as calculated by Michaelis-Menten kinetics into the brain by using a simplified ATD protocol in humans. The simplified composition of only two AAs, the lower overall AA amount, and the appropriate tolerance are characteristics of the newly developed ATDPHE/LEU protocol. Future studies focusing on the effects of the ATDPHE/LEU protocol and its respective control condition on CSF 5-HIAA concentrations, as well as neurochemical studies in rodents, are needed to further validate this newly developed AA mixture before definite conclusions about its usability in ATD-related research in humans, its specificity, and additional effects can be made.

Effects of dietary tryptophan and phenylalanine-tyrosine depletion on phasic alertness in healthy adults - A pilot study.

BACKGROUND: The synthesis of the neurotransmitters serotonin (5-HT) and dopamine (DA) in the brain can be directly altered by dietary manipulation of their relevant precursor amino acids (AA). There is evidence that altered serotonergic and dopaminergic neurotransmission are both associated with impaired attentional control. Specifically, phasic alertness is one specific aspect of attention that has been linked to changes in 5-HT and DA availability in different neurocircuitries related to attentional processes. The present study investigated the impact of short-term reductions in central nervous system 5-HT and DA synthesis, which was achieved by dietary depletion of the relevant precursor AA, on phasic alertness in healthy adult volunteers; body weight-adapted dietary tryptophan and phenylalanine-tyrosine depletion (PTD) techniques were used. METHODS: The study employed a double-blind between-subject design. Fifty healthy male and female subjects were allocated to three groups in a randomized and counterbalanced manner and received three different dietary challenge conditions: acute tryptophan depletion (ATD, for the depletion of 5-HT; N=16), PTD (for the depletion of DA; N=17), and a balanced AA load (BAL; N=17), which served as a control condition. Three hours after challenge intake (ATD/PTD/BAL), phasic alertness was assessed using a standardized test battery for attentional performance (TAP). Blood samples for AA level analyses were obtained at baseline and 360 min after the challenge intake. RESULTS: Overall, there were no significant differences in phasic alertness for the different challenge conditions. Regarding PTD administration, a positive correlation between the reaction times and the DA-related depletion magnitude was detected via the lower plasma tyrosine levels and the slow reaction times of the first run of the task. In contrast, higher tryptophan concentrations were associated with slower reaction times in the fourth run of the task in the same challenge group. CONCLUSION: The present study is the first to demonstrate preliminary data that support an association between decreased central nervous system DA synthesis, which was achieved by dietary depletion strategies, and slower reaction times in specific runs of a task designed to assess phasic alertness in healthy adult volunteers; these findings are consistent with previous evidence that links phasic alertness with dopaminergic neurotransmission. A lack of significant differences between the three groups could be due to compensatory mechanisms and the limited sample size, as well as the dietary challenge procedures administered to healthy participants and the strict exclusion criteria used. The potential underlying neurochemical processes related to phasic alertness should be the subject of further investigations.

Migration background and juvenile mental health: a descriptive retrospective analysis of diagnostic rates of psychiatric disorders in young people.

INTRODUCTION: This article presents diagnostic rates for specific mental disorders in a German pediatric inpatient population over a period of 20 years with respect to migration background and socioeconomic status (SES). METHODS: Diagnostic data were obtained over a period of 20 years from 8,904 patients who visited a child and adolescent psychiatry mental health service in Germany. Data from 5,985 diagnosed patients (ICD-9 and ICD-10 criteria) were included with respect to gender, migration background, and SES. RESULTS: Migration- and gender-specific effects were found for both periods of assessment. The group of boys with a migration background showed significantly higher rates of reactions to severe stress, adjustment disorders, and posttraumatic stress disorder compared to their male, non-migrant counterparts. Conversely, boys without a migration background showed a significantly higher percentage rate of hyperkinetic disorders than male migrants. Similar results were found for female migrants in the latter assessment period (ICD-10). In addition, female migrants showed lower rates of emotional disorders whose onset occurs in childhood compared to their non-migrant counterparts. CONCLUSIONS: Data from this investigation provide preliminary evidence that the prevalence of various psychiatric disorders in children and adolescents is influenced by migration background and SES.

Effects of acute tryptophan depletion on brain serotonin function and concentrations of dopamine and norepinephrine in C57BL/6J and BALB/cJ mice.

Acute tryptophan depletion (ATD) is a method of lowering brain serotonin (5-HT). Administration of large neutral amino acids (LNAA) limits the transport of endogenous tryptophan (TRP) across the blood brain barrier by competition with other LNAAs and subsequently decreases serotonergic neurotransmission. A recent discussion on the specificity and efficacy of the ATD paradigm for inhibition of central nervous 5-HT has arisen. Moreover, side effects such as vomiting and nausea after intake of amino acids (AA) still limit its use. ATD Moja-De is a revised mixture of AAs which is less nauseating than conventional protocols. It has been used in preliminary clinical studies but its effects on central 5-HT mechanisms and other neurotransmitter systems have not been validated in an animal model. We tested ATD Moja-De (TRP-) in two strains of mice: C57BL/6J, and BALB/cJ, which are reported to have impaired 5-HT synthesis and a more anxious phenotype relative to other strains of mice. ATD Moja-De lowered brain TRP, significantly decreased 5-HT synthesis as indexed by 5-HTP levels after decarboxlyase inhibition, and lowered 5-HT and 5-HIAA in both strains of mice, however more so in C57BL/6J than in BALB/cJ. Dopamine and its metabolites as well as norepinephrine were not affected. A balanced (TRP+) control mixture did not raise 5-HT or 5-HIAA. The present findings suggest that ATD Moja-De effectively and specifically suppresses central serotonergic function. These results also demonstrate a strain-specific effect of ATD Moja-De on anxiety-like behavior.

Attentional performance, age and scholastic achievement in healthy children.

BACKGROUND: Attentional processes in children play a critical role in daily school demands and accomplishments. Studies on the association of attentional processes with school achievement and age in healthy school children are scarce. The aim of the present study was to identify correlations between dimensions of attentional performance, scholastic achievement and age. METHODOLOGY/PRINCIPAL FINDINGS: An extensive testing battery was used to assess a wide range of attentional dimensions. A principal component analysis revealed three factors that are related to attentional performance (distractibility, lapses of attention, cognitive speed). Age was negatively associated with distractibility, lapses of attention and cognitive speed, indicating that distractibility and lapses of attention decreased with age in healthy children and resulted in lower cognitive speed. CONCLUSIONS/SIGNIFICANCE: Attentional processes in healthy children should be measured in relation to distractibility, lapses of attention and cognitive speed.

The effects of acute tryptophan depletion on reactive aggression in adults with attention-deficit/hyperactivity disorder (ADHD) and healthy controls.

BACKGROUND: The neurotransmitter serotonin (5-HT) has been linked to the underlying neurobiology of aggressive behavior, particularly with evidence from studies in animals and humans. However, the underlying neurobiology of aggression remains unclear in the context of attention-deficit/hyperactivity disorder (ADHD), a disorder known to be associated with aggression and impulsivity. We investigated the effects of acute tryptophan depletion (ATD), and the resulting diminished central nervous serotonergic neurotransmission, on reactive aggression in healthy controls and adults with ADHD. METHODOLOGY/PRINCIPAL FINDINGS: Twenty male patients with ADHD and twenty healthy male controls were subjected to ATD with an amino acid (AA) beverage that lacked tryptophan (TRP, the physiological precursor of 5-HT) and a TRP-balanced AA beverage (BAL) in a double-blind, within-subject crossover-study over two study days. We assessed reactive aggression 3.25 hours after ATD/BAL intake using a point-subtraction aggression game (PSAG) in which participants played for points against a fictitious opponent. Point subtraction was taken as a measure for reactive aggression. Lowered rates of reactive aggression were found in the ADHD group under ATD after low provocation (LP), with controls showing the opposite effect. In patients with ADHD, trait-impulsivity was negatively correlated with the ATD effect on reactive aggression after LP. Statistical power was limited due to large standard deviations observed in the data on point subtraction, which may limit the use of this particular paradigm in adults with ADHD. CONCLUSIONS/SIGNIFICANCE: Together with previous findings, the data provide preliminary evidence of an inverse association between trait-impulsivity and the ATD effect on reactive aggression after LP (as assessed by the PSAG) in patients with ADHD and that this relationship can be found in both adolescents and adults. Because of limited statistical power larger sample sizes are needed to find main effects of ATD/BAL administration on reactive aggression in adults with ADHD.

Differences in serum zn levels in acutely ill and recovered adolescents and young adults with anorexia nervosa--a pilot study.

Preliminary evidence suggests that changes in zinc (Zn) metabolism are associated with anorexia nervosa (AN). However, data are scarce regarding potential differences in serum Zn concentrations in adolescent and young adult patients with AN. It was the aim of the present pilot study to compare serum Zn concentrations between acutely ill and remitted adolescent and young adult female patients with AN and female controls. Zn concentrations were higher in remitted compared with acutely ill patients. Zn concentrations were also higher in remitted patients compared with controls, but there was no significant difference in Zn concentrations between acutely ill patients and controls. The present study provides preliminary evidence for differences in serum Zn status in recovered patients with AN. These differences are likely influenced by reported food preferences, in particular as regards Ca²âº and phosphorus-containing foods. However, because of limited statistical power, future research involving larger samples is necessary.

[Psychopharmacotherapy improves psychosocial functioning in adolescents with borderline personality disorder]. / Psychopharmakotherapie verbessert das psychosoziale Funktionsniveau bei adoleszenten Patienten mit Borderline-Persönlichkeitsstörung.

Treatment of patients with borderline personality disorder (BPD) has undergone significant changes within the last decades. Although there is no specific pharmacological treatment approach for BPD per se, there is evidence for a beneficial effect of psychopharmacological treatment in adults. As there is a significant lack of data regarding such treatment in adolescents we aim to investigate the effects of psychopharmacological treatment retrospectively focusing on the first period of treatment. The study sample comprised 2,778 subjects (inpatients and outpatients) from a population on demand of psychiatric services referred to our department, with 39 patients (aged 16,2 +/- 1,7 yrs.) having a diagnosis of BPD. Psychosocial functioning as indexed on axis VI was assessed within the BADO documentation algorithm before and after treatment. Effects of treatment in terms of improved psychosocial functioning under different medications as well as different risk variables were assessed. Moreover, medicated and un-medicated patients were compared as regards effects of treatment. Upon admission inpatients showed a significantly higher impairment in their psychosocial functioning compared with outpatients. There was no significant difference between medicated and un-medicated patients with respect to the different risk variables assessed. Psychosocial functioning improved under pharmacological treatment, with this effect being unrelated to in- or outpatient status. About 80% of the prescribed medications were antidepressants and neuroleptics, with a combination of two drugs being the most frequent treatment approach to be observed. The data of the present study indicate that psychopharmacological treatment of adolescents with BPD can improve psychosocial functioning.

Bipolar disorder in children and adolescents in Germany: national trends in the rates of inpatients, 2000-2007.

OBJECTIVES: Increasing admission and prevalence rates of bipolar disorder (BD) are a matter of controversy in international child and adolescent psychiatry. We seek to contribute to this discussion by presenting data obtained in a population of German children and adolescents. METHODS: Nationwide, whole population changes in inpatient admissions of BD and other psychiatric disorders between 2000 and 2007 were analyzed in individuals aged up to 19 years using registry data from the German Federal Health Monitoring System. RESULTS: Inpatient admissions for BD in individuals aged up to 19 years increased from 1.13 to 1.91 per 100,000 or 68.5% between 2000 and 2007 (odds ratio: 1.69; 95% confidence interval: 1.41-2.02), with a nonsignificant decline in children less than 15 years and the largest relative increase in adolescents aged 15-19 years. Inpatient rates for depressive disorders increased by 219.6% and for hyperkinetic disorder by 111.3%. Conduct disorders increased by 18.1%, considerably less than the 38.1% general rise for all mental disorders in children and adolescents. The only significant decline in a diagnostic category occurred for psychotic disorders (-11.8%). BD inpatient admission represented only 0.22% of all mental disorder admissions in 2000 and 0.27% in 2007. CONCLUSIONS: An elevation of inpatient admissions of BD in Germany in adolescents was detected, exceeding the general trend for increased mental disorder admissions. The results may indicate a higher clinical awareness and appreciation of mood symptoms at earlier ages and, in part, a reconceptualization of previously diagnosed psychotic disorders in youth. However, a diagnosis of BD in youngsters is still extremely rare in Germany. Diagnoses were based on the judgment of the treating physician. A correction for multiple admissions in the data set is not possible.

[Psychopharmacotherapy in adolescents with borderline personality disorder in inpatient and outpatient psychiatric treatment]. / Psychopharmakotherapie einer ambulanten und stationären Inanspruchnahmepopulation adoleszenter Patienten mit Borderline-Persönlichkeitsstörung.

OBJECTIVE: The majority of adult patients with borderline personality disorder (BPD) are treated with psychotropic drugs. However, there are no data on psychotropic therapy in adolescents. This study examines the prevalence of BPD in an adolescent population undergoing either inpatient or outpatient psychiatric treatment and assesses psychotropic prescription patterns in adolescent in- and outpatients with BPD. METHODS: Out of a population of adolescents undergoing psychiatric treatment over a seven-year observation period, 58 adolescent patients with BPD (16.7 +/- 2.5 years) were investigated retrospectively with regard to their first episode of treatment, type of medication, and different risk variables. RESULTS: Out of the investigated population, 37 inpatients and 21 outpatients received treatment. Inpatients were shown to have higher rates of risk variables (approx. 68% with co-morbid disorders and approx. 49% with self-harmful behaviour, significantly (p < .001) more attempted suicides in their patient history) and higher rates of psychotropic treatment (p < .001). Antidepressants (SSRI and NaSSA) were most commonly prescribed, followed by neuroleptics. More than 50% of the medicated patients were treated with multiple psychotropic drugs administered simultaneously. CONCLUSIONS: Pharmacotherapy in BPD has a high and increasing therapeutic value, with the prescription of psychotropic drugs being primarily symptom-orientated. Pharmacotherapy of co-morbid disorders should be accorded equal treatment priority. In line with this, psychotropic treatment of BPD in adolescents is increasingly important. Inpatient adolescents are more burdened in terms of psychiatric risk variables, and also receive medication more often.

Diminished central nervous 5-HT neurotransmission and mood self-ratings in children and adolescents with ADHD: no clear effect of rapid tryptophan depletion.

INTRODUCTION: Research on 5-HT-functioning in adult patients and healthy subjects using rapid tryptophan depletion (RTD) has indicated weak but stable effects on mood ratings. Altered mood in children and adolescents with attention-deficit/hyperactivity disorder (ADHD) can confound the differential diagnosis between severe ADHD and mood disorders such as pediatric bipolar disorder. The present study investigated the effects of RTD induced lowered central nervous 5-HT-levels on mood self-ratings in children with ADHD. METHODS: Seventeen boys with ADHD participated in the study in a double-blind within-subject crossover-design. They were administered RTD within an amino acid drink lacking tryptophan, thus lowering central nervous 5-HT-synthesis. On another day they received a placebo. Self-rated mood was assessed on both days at baseline conditions and at three different post-drink time-points. RESULTS: RTD had no clear effect on mood within the whole sample. Low scorers on venturesomeness were more strongly affected by RTD in terms of feelings of inactivity and negative feelings compared to high venture patients. CONCLUSIONS: Our data did not show a significant effect of RTD on mood self-ratings. However, the findings must be considered as preliminary and require further replication, in particular as they could be due to sampling bias.

Reduced serotonergic functioning changes heart rate in ADHD.

Reduced mean heart rate (HR) was shown to be a biophysiological marker for aggression, which in turn was proven to be related to changed serotonergic neurotransmission. A total of 16 ADHD-diagnosed boys were subjected to rapid tryptophan depletion (RTD) and a placebo in a double-blind within-subject crossover-design. Mean HR was assessed under RTD/placebo. Low impulsive patients behaving aggressively under RTD showed a lowered HR under RTD versus placebo. Diminished 5-HT functioning was associated with lowered HR and aggressive behaviour.