Affective state and EEG sleep profile in response to rapid tryptophan depletion in recently recovered nonmedicated depressed individuals

Constipation is associated with depression of any severity, but not with suicidal ideation: insights from a large cross-sectional study

OBJECTIVE

The association between constipation and depression or suicidal ideation (SI) has not been adequately studied. This study aims to examine whether constipation is associated with depression or SI in US adults.

METHOD

4,562 adults aged 20 and older were selected from the National Health and Nutrition Examination Survey 2009-2010 for the sample. The Bowel Health Questionnaire provided constipation information. Clinical depression and depression severity were assessed by the validated Patient Health Questionnaide-9 (PHQ-9), and item 9 of the PHQ-9 assessed SI. Adjusted odds ratios (ORs) were calculated using multivariate logistic regression models. Stability of the results was ensured by a subgroup analysis.

RESULT

After adjusting for covariates such as demographics, risk behaviors, associated comorbidities, dietary intake, and related medications, the PHQ-9 score and clinical depression were both significantly associated with constipation, with ORs and 95%CIs of 1.13 (1.10-1.16) and 3.76 (2.65-5.34). Depression of all severities was also significantly associated with constipation. The ORs and 95%CIs of constipation with mild depression, moderate depression, and moderately severe to severe depression were 2.21 (1.54-3.16), 3.69 (2.34-5.81) and 6.84 (4.19-11.15), respectively. Subgroup analyses showed no statistically significant interactions (P > 0.05), and the association was stronger in men than in women (OR: 7.81, 95%CI: 3.67-16.61 vs OR: 3.46, 95%CI: 2.31-5.19). The association between constipation and SI was not significant (OR: 1.36, 95%CI: 0.78-2.37).

CONCLUSION

In conclusion, constipation was significantly associated with depression of any severity, but not with SI, suggesting that enough attention should be paid to the emotional and psychological status of patients with constipation, especially male patients.

Relation of plasma tryptophan concentrations during pregnancy to maternal sleep and mental well-being: The GUSTO cohort

BACKGROUND

Evidence suggests a relation between plasma tryptophan concentrations and sleep and mental well-being. As no studies have been performed in pregnant women, we studied the relation of plasma tryptophan concentrations during pregnancy with sleep quality, and mood during and after pregnancy.

METHODS

Pregnant women (n = 572) from the Growing Up in Singapore Towards healthy Outcomes study completed the Pittsburgh Sleep Quality Index (PSQI), the Edinburgh Postnatal Depression Scale (EPDS) and the State-Trait Anxiety Inventory (STAI) at 26-28 weeks gestation and three months post-delivery. Plasma tryptophan concentrations were measured at 26-28 weeks gestation. Poisson regressions estimated prevalence ratios (PR) for the association between tryptophan and poor sleep quality (PSQI global score > 5), probable antenatal depression (EPDS ≥ 15) and probable anxiety (STAI-state ≥ 41) were calculated adjusting for covariates.

RESULTS

Mean plasma tryptophan concentrations was 48.0µmol/L (SD: 8.09). Higher plasma tryptophan concentrations were associated with a lower prevalence of antenatal poor sleep quality adjusting for covariates [PR: 0.88 (95% CI 0.80, 0.97) per 10µmol/L], especially in those participants who also suffered from anxiety symptoms [PR: 0.80 (95% CI 0.67, 0.95)]. No associations were observed between tryptophan concentrations during pregnancy and postnatal sleep quality or mental well-being.

LIMITATION

Subjective measures were used to assess sleep and mental well-being.

CONCLUSIONS

We observed that higher plasma tryptophan concentrations were associated with a 12% lower prevalence of poor sleep quality during pregnancy, in particular among those with anxiety symptoms. These findings suggest the importance of having adequate tryptophan concentrations during pregnancy.

Advances in research of sleep disturbance in patients with hepatitis C virus infection

According to the WHO statistics, approximately 171 million people are infected by hepatitis C virus (HCV) worldwide. Chronic HCV infection is associated with physical and mental symptoms including fatigue, sleep disturbance, and depression that adversely affect quality of life. But sleep disturbance has received little attention in the literature, with the exception of sleep changes noted in patients with cirrhosis and end-stage liver disease. More studies focusing on the role of chronic hepatitis C (CHC) infection in the development of sleep disorders are needed. Increased knowledge about the mechanisms behind the pathogenesis of sleep disturbance in patients with CHC will help us develop appropriate treatments.

Rapid tryptophan depletion following cognitive behavioural therapy for panic disorder

OBJECTIVE

The aim of this study was to examine the effect of rapid tryptophan depletion (RTD) combined with a panicogenic challenge in patients with panic disorder who had responded to treatment with cognitive behavioural therapy (CBT). We hypothesised that RTD (compared with the control drink) would result in an increase in anxiety symptoms when provoked by a panicogenic challenge with the benzodiazepine antagonist, flumazenil.

METHODS

Nine patients with panic disorder who had responded to CBT received a tryptophan-free amino acid drink on one occasion and a control drink on the other in a double-blind crossover design. In addition, they received flumazenil and placebo infusions on each day.

RESULTS

Our hypothesis regarding the effects of RTD was supported by findings of a significant interaction between RTD and flumazenil on measures from visual analogues scales (total) and the Spielberger State Anxiety inventory. A somewhat unexpected finding was that in this group of CBT responders, the panicogenic effect of flumazenil was not completely blocked by treatment. This meant that although four of the nine subjects (44%) reported a panicogenic effect of flumazenil on the RTD day, this was not significantly different from the rate of panic attacks in response to flumazenil on the control day.

CONCLUSION

We suggest that the partial return of symptoms in response to flumazenil reflects a vulnerability to RTD in this group of panic disorder patients who had responded to treatment with CBT.

Equivalent effects of acute tryptophan depletion on REM sleep in ecstasy users and controls

INTRODUCTION

This study sought to test the association between 3,4-methylenedioxymethamphetamine use, serotonergic function and sleep.

MATERIALS AND METHODS

Ambulatory polysomnography was used to measure three nights sleep in 12 ecstasy users and 12 controls after screening (no intervention), a tryptophan-free amino acid mixture (acute tryptophan depletion (ATD)) and a tryptophan-supplemented control mixture.

RESULTS

ATD significantly decreased rapid eye movement (REM) sleep onset latency, increased the amount of REM sleep and increased the amount of stage 2 sleep in the first 3 h of sleep. There was no difference between ecstasy users' and controls' sleep on the screening night or after ATD.

DISCUSSION

These findings imply that the ecstasy users had not suffered significant serotonergic damage as indexed by sleep.

The effects of tryptophan depletion on neural responses to emotional words in remitted depression

BACKGROUND

Major depressive disorder (MDD) has been associated with both dysfunction of the central serotonergic system and abnormal responses to emotional stimuli. We used acute tryptophan depletion (ATD) to investigate the effect of temporarily reducing brain serotonin synthesis on neural and behavioral responses to emotional stimuli in remitted MDD subjects (rMDD) and healthy control subjects.

METHODS

Twenty control subjects and 23 rMDD subjects who had been unmedicated and in remission for > or =3 months completed the study. Following tryptophan or sham depletion, participants performed an emotional-processing task during functional magnetic resonance imaging. In addition, resting state regional blood flow was measured using arterial spin labeling.

RESULTS

Neither group exhibited significant mood change following ATD. However, tryptophan depletion differentially affected the groups in terms of hemodynamic responses to emotional words in a number of structures implicated in the pathophysiology of MDD, including medial thalamus and caudate. These interactions were driven by increased responses to emotional words in the control subjects, with little effect in the patients under the ATD condition. Following ATD, habenula blood flow increased significantly in the rMDD subjects relative to the control subjects, and increasing amygdala blood flow was associated with more negative emotional bias score across both groups.

CONCLUSIONS

These data provide evidence for elevated habenula blood flow and alterations in the neural processing of emotional stimuli following ATD in rMDD subjects, even in the absence of overt mood change. However, further studies are required to determine whether these findings represent mechanisms of resilience or vulnerability to MDD.

Rapid eye movement (REM) sleep: an endophenotype for depression

Disturbed sleep is one of the hallmark signs of depression. After successful treatment, many of these signs disappear; however, changes in rapid eye movement (REM) sleep may persist and even predict recurrence of depression. High-risk studies have established these alterations to be not only biological scars but true endophenotypes for depression. REM sleep changes are mediated by the noradrenergic, serotonergic, and cholinergic systems and are under strong genetic control. REM sleep has a crucial role for brain maturation and is inhibited during ontogeny. Lack of this inhibition may predispose an individual to depression. Findings regarding the CREB gene support REM sleep's role in depression. The combination of psychopathology and neurobiological measures, such as REM sleep parameters, will help to improve genetic studies and therefore increase the knowledge of relevant pathways for depression. This could facilitate development of preventive and therapeutic measures.

Challenge tests of monoaminergic systems: neurophysiological aspects

Monoaminergic challenge tests allow investigating central nervous changes in humans under acute depletion of specific neurotransmitters (5-HT, DA, NE). Along with studies using alpha-methyl-para-tyrosine test (AMPT) and phenylalanine/tyrosine depletion test (APTD), the tryptophan depletion test (ATDT) represents the currently most established human challenge tool for the assessment of brain serotonin functioning. Neurophysiological studies in healthy and clinical samples may contribute to the search for a non-invasive and reliable biological marker of monoaminergic vulnerability or dysfunction. In the design of these studies, various biochemical and methodological aspects have to be taken into account. This article focuses on electrophysiological methodology and results of monoamine depletion studies (i.e., electroencephalography, magnetoencephalography, polysomnography, auditory evoked potentials and startle response).

Mood is indirectly related to serotonin, norepinephrine and dopamine levels in humans: a meta-analysis of monoamine depletion studies

Dysfunction in the monoamine systems of serotonin (5-HT), norepinephrine (NE) and dopamine (DA) may causally be related to major depressive disorder (MDD). Monoamine depletion studies investigate the direct effects of monoamines on mood. Acute tryptophan depletion (ATD) or para-chlorophenylalanine (PCPA) deplete 5-HT, acute phenylalanine/tyrosine depletion (APTD) or alpha-methyl-para-tyrosine (AMPT) deplete NE/DA. Available depletion studies found conflicting results in heterogeneous populations: healthy controls, patients with previous MDD in remission and patients suffering from MDD. The decrease in mood after 5-HT and NE/DA depletion in humans is reviewed and quantified. Systematic search of MEDLINE and EMBASE (1966-October 2006) and cross-references was carried out. Randomized studies applying ATD, PCPA, APTD or AMPT vs control depletion were included. Pooling of results by meta-analyses was stratified for studied population and design of the study (within or between subjects). Seventy-three ATD, 2 PCPA, 10 APTD and 8 AMPT studies were identified of which 45 ATD and 8 APTD studies could be meta-analyzed. 5-HT or NE/DA depletion did not decrease mood in healthy controls. 5-HT or NE/DA depletion slightly lowered mood in healthy controls with a family history of MDD. In drug-free patients with MDD in remission, a moderate mood decrease was found for ATD, without an effect of APTD. ATD induced relapse in patients with MDD in remission who used serotonergic antidepressants. In conclusion, monoamine depletion studies demonstrate decreased mood in subjects with a family history of MDD and in drug-free patients with MDD in remission, but do not decrease mood in healthy humans. Although depletion studies usefully investigate the etiological link of 5-HT and NE with MDD, they fail to demonstrate a causal relation. They presumably clarify a vulnerability trait to become depressed. Directions for further investigation of this vulnerability trait are proposed.

Sleep disturbances, psychiatric disorders, and psychotropic drugs

Brain neurotransmitter dysfunctions involved in the pathophysiological processes of psychiatric disorders are likely to be reflected by concomitant alterations in sleep continuity and architecture. Since the corrective effects of psychotropic drugs on dysfunctional neurotransmission systems can be evidenced through polysomnographic recordings, one may consider sleep as a kind of “window” on the neurobiology of psychiatric disorders. During the last 10 years, major breakthroughs in our understanding of sleep-wake mechanisms have provided some indications on how psychotropic drugs could influence the sleep-wake cycle. In this review, recent inroads into the understanding of sleep regulatory neural mechanisms are introduced and discussed in terms of the effects of psychotropic drugs. The relationship between the patho-physiological process of a disease, its consequence on sleep, and the corrective effect of a psychotropic drug are exemplified by two psychopathological states: substance withdrawal and major depression. One may conclude that polysomnographic recordings are a unique noninvasive tool to analyze brain functioning, and are particularly well suited to evaluating the objective effects of new psychotropic drugs.