Serotonin, carbohydrates, and atypical depression

Microbiome and immuno-metabolic dysregulation in patients with major depressive disorder with atypical clinical presentation

Depression is highly prevalent (6% 1-year prevalence) and is the second leading cause of disability worldwide. Available treatment options for depression are far from optimal, with response rates only around 50%. This is most likely related to a heterogeneous clinical presentation of major depression disorder (MDD), suggesting different manifestations of underlying pathophysiological mechanisms. Poorer treatment outcomes to first-line antidepressants were reported in MDD patients endorsing an "atypical" symptom profile that is characterized by preserved reactivity in mood, increased appetite, hypersomnia, a heavy sensation in the limbs, and interpersonal rejection sensitivity. In recent years, evidence has emerged that immunometabolic biological dysregulation is an important underlying pathophysiological mechanism in depression, which maps more consistently to atypical features. In the last few years human microbial residents have emerged as a key influencing variable associated with immunometabolic dysregulations in depression. The microbiome plays a critical role in the training and development of key components of the host's innate and adaptive immune systems, while the immune system orchestrates the maintenance of key features of the host-microbe symbiosis. Moreover, by being a metabolically active ecosystem commensal microbes may have a huge impact on signaling pathways, involved in underlying mechanisms leading to atypical depressive symptoms. In this review, we discuss the interplay between the microbiome and immunometabolic imbalance in the context of atypical depressive symptoms. Although research in this field is in its infancy, targeting biological determinants in more homogeneous clinical presentations of MDD may offer new avenues for the development of novel therapeutic strategies for treatment-resistant depression.

Depression development: From lifestyle changes to motivational deficits

Until now, depression research has taken a surprisingly narrow approach to modelling the disease, mainly focusing on some form of psychomotor retardation within a mechanistic framework of depression etiology. However, depression has many symptoms and each is associated with a vast number of substrates. Thus, to deepen our insights, this SI ("Depression Symptoms") reviewed the behavioral and neurobiological sequelae of individual symptoms, specifically, psychomotor retardation, sadness, low motivation, fatigue, sleep/circadian disruption, weight/appetite changes, and cognitive affective biases. This manuscript aims to integrate the most central information provided by the individual reviews. As a result, a dynamic model of depression development is proposed, which views depression as a cumulative process, where different symptoms develop at different stages, referred to as early, intermediate, and advanced, that require treatment with different pharmaceutical agents, that is, selective serotonin reuptake inhibitors early on and dopamine-based antidepressants at the advanced stage. Furthermore, the model views hypothalamic disruption as the source of early symptoms and site of early intervention. Longitudinal animal models that are capable of modelling the different stages of depression, including transitions between the stages, may be helpful to uncover novel biomarkers and treatment approaches.

Oxaloacetate reduces emotional symptoms in premenstrual syndrome (PMS): results of a placebo-controlled, cross-over clinical trial

Objective

Premenstrual syndrome (PMS) affects millions of women. While over-the-counter products have helped with the physical symptoms of PMS, emotional symptoms have been less well supported. The objective of this trial was to measure the effect of an oxaloacetate/vitamin C combination on the major emotional symptoms of PMS, including depression, anxiety, perceived stress, aggression, and suicidal ideation.

Methods

Forty-eight women experiencing PMS completed a baseline survey comprising the Beck's Depression Inventory, Cohen Perceived Stress Scale, Generalized Anxiety Disorder Test, and Buss-Perry Aggression Questionnaire. After baseline measurements, participants were randomly assigned to take either 2 capsules of 100 mg oxaloacetate/150 mg ascorbic acid, or 2 capsules of rice flour (placebo) for their entire menstrual cycle. At menstruation, the women completed the 4 surveys again. The women then switched capsules in a cross-over design and continued the study for an additional menstrual cycle. The final assessment was repeated at menstruation. Statistical analysis of the 4 surveys was performed to examine efficacy.

Results

Oxaloacetate/vitamin C supplementation during PMS significantly improved depression, perceived stress, anxiety, aggression, and suicidal ideation. The mean improvement in depression was 54.1%, 35.8% for perceived stress, 51.43% for generalized anxiety, and 17.8% for aggression. Suicidal ideation was reduced by 47.9%. All results were highly significant.

Conclusion

A combination of oxaloacetate and vitamin C supplementation helped to alleviate depression, anxiety, perceived stress, aggression, and suicidal ideation symptoms associated with PMS.

Trial Registration

ClinicalTrials.gov Identifier: NCT03509714.

Association between energy drink intake, sleep, stress, and suicidality in Korean adolescents: energy drink use in isolation or in combination with junk food consumption

BACKGROUND

A considerable amount of research suggests that the frequent use of caffeinated energy drinks may be associated with undesirable effects, particularly so in children and adolescents. This study aimed to investigate the associations between energy drink intake and mental health problems, in isolation or in combination with junk food consumption, in a nationally representative sample of Korean adolescents.

METHODS

Data from the 2015 Korean Youth Risk Behavior Web-Based Survey, collected from 68,043 adolescents aged 12-18 years (mean age 15.09 ± 1.72 years), were analyzed. Questionnaires were administered to collect information related to dietary behavior including energy drink intake and junk food consumption. Single item measures of sleep dissatisfaction, stress, depression, suicidal ideation, suicide plan, and suicide attempt were also administered. Associations between energy drink intake and sleep dissatisfaction, perceived severe stress, persistent depressive mood, and suicidality were investigated, and a multivariate approach was taken so that additional variance from demographic and lifestyle factors could be controlled for statistically.

RESULTS

Energy drink intake was significantly associated with sleep dissatisfaction (adjusted odd ratios [AORs] = 1.64 and 1.25), severe stress (AORs = 2.23 and 1.38), depressive mood (AOR = 2.59 and 1.51), suicidal ideation (AORs = 3.14 and 1.43), suicide plan (AORs = 4.65 and 1.78), and suicide attempt (AORs = 6.79 and 1.91), with a higher risk for more frequent use of energy drinks (≥5 times/wk) than for less frequent use (1-4 times/wk). The detrimental effect of energy drinks on mental health was particularly prominent in frequent junk food consumers.

CONCLUSIONS

Our data suggest that energy drink intake had detrimental effects related to stress, sleep dissatisfaction, mood, and suicidality, in isolation or in combination with junk food consumption, in Korean adolescents. However, the cross-sectional study design prevents our ability to assess causal relationships.

Chocolate and health-related quality of life: a prospective study

Background

Chocolate consumption has been associated with a short-term reduction in blood pressure and cholesterol, and improvement of insulin sensitivity; however, participants could not be aware of presenting hypertension or hypercholesterolemia. Moreover, the effect of chocolate on mental health is uncertain. This study assessed the association of regular chocolate consumption with the physical (PCS) and mental (MCS) components of health-related quality of life (HRQL).

Materials and methods

We analyzed data from a cohort of 4599 individuals recruited in 2008–2010 and followed-up once prospectively to January 2013 (follow-up mean: 3.5 years). Regular chocolate consumption was assessed at baseline with a validated diet history. HRQL was assessed with the SF-12 v.2 at baseline and at follow-up. Analyses were performed with linear regression and adjusted for the main confounders, including HRQL at baseline.

Results

At baseline, 72% of the study participants did not consume chocolate, 11% consumed ≤10 g/day and 17% >10 g/day. Chocolate consumption at baseline did not show an association with PCS and MCS of the SF-12 measured three years later. Compared to those who did not consume chocolate, the PCS scores were similar in those who consumed ≤10g/day (beta: -0.07; 95% confidence interval (95% CI): -0.94 to 0.80) and in those who consumed >10g/day (beta: 0.02; 95% CI:-0.71 to 0.75); corresponding figures for the MCS were 0.29; 95% CI: -0.67 to 1.26, and -0.57; 95%CI: -1.37 to 0.23. Similar results were found for sex, regardless of obesity, hypertension, hypercholesterolemia, diabetes or depression.

Conclusions

No evidence was found of an association between chocolate intake and the physical or mental components of HRQL.

[Analysis on content of serum monoamine neurotransmitters in macaques with anger-in-induced premenstrual syndrome and liver-qi depression syndrome]

OBJECTIVE

To observe the changes in content of monoamine neurotransmitters in the serum of rhesus macaques, and explore the role of serum monoamine neurotransmitters in premenstrual syndrome (PMS) and liver-qi depression induced by anger-in emotion.

METHODS

Social level pressure was applied on 24 female macaques to induce the angry emotional reaction, and then nine of the low-status macaques with anger-in emotional reaction were screened out and were divided into anger-in emotion group, PMS and liver-qi depression group (model group) and Jingqianshu Granule group. Macaques in the last two groups were suffered extruding in a pack cage for inducing PMS liver-qi depression. After 5 d of extruding, experimental animals were evaluated according to the emotional evaluation scale, meanwhile, macaque serum of follicular phase and middle-late luteal phase was collected to analyze the content of serum norepinephrine, dopamine, and 5-hydroxytryptamine.

RESULTS

Compared with the normal control group, the scores of depression of the model group and the anger-in emotion group evaluated with emotional evaluation scale were significantly increased (P<0.01, P<0.05); while the score of the model group was significantly higher than that of the anger-in emotion group (P<0.05), and it returned to normal after Jingqianshu Granule treatment. As compared to the normal control group, serum monoamine neurotransmitter levels of the model group and the anger-in emotion group were increased (P<0.05, P<0.01), and the serum monoamine neurotransmitter levels of the model group were significantly higher than those of the anger-in emotion group (P<0.05), while there was no significant difference when compared with the normal control group after the treatment.

CONCLUSION

Anger-in emotion can induce liver-qi depression syndrome which is related to the changes in monoamine neurotransmitters.

Clinical differentiation of bipolar II disorder from personality-based "emotional dysregulation" conditions

BACKGROUND

The non-psychotic mood swings experienced by those with a bipolar II disorder can lead to diagnostic dilemmas, especially in differentiating this condition from personality styles marked by emotional dysregulation. This paper provides a clinical vignette and then offers some indicative parameters that might assist differentiation.

METHODS

A clinical vignette is provided of a patient who had longitudinal features consistent with either a bipolar II disorder or of distinct personality-based dysregulation and the reader is invited to consider the likely diagnosis. A relevant literature is overviewed and, in conjunction with clinical observations, diagnostic parameters for differentiating the two diagnostic groupings are derived.

RESULTS

It is suggested that the derived parameters assist diagnostic clarification in most instances but reference back to the clinical vignette tempers that level of confidence.

LIMITATIONS

Many of the identified differentiating features are clinically derived and are subject to limitations of clinical observation and biases.

CONCLUSIONS

The importance of differentiating a primary bipolar II disorder from a personality-based condition is of high clinical importance. This overview seeks to advance the objective.

Potential animal models of seasonal affective disorder

Seasonal affective disorder (SAD) is characterized by depressive episodes during winter that are alleviated during summer and by morning bright light treatment. Currently, there is no animal model of SAD. However, it may be possible to use rodents that respond to day length (photoperiod) to understand how photoperiod can shape the brain and behavior in humans. As nights lengthen in the autumn, the duration of the nightly elevation of melatonin increase; seasonally breeding animals use this information to orchestrate seasonal changes in physiology and behavior. SAD may originate from the extended duration of nightly melatonin secretion during fall and winter. These similarities between humans and rodents in melatonin secretion allows for comparisons with rodents that express more depressive-like responses when exposed to short day lengths. For instance, Siberian hamsters, fat sand rats, Nile grass rats, and Wistar rats display a depressive-like phenotype when exposed to short days. Current research in depression and animal models of depression suggests that hippocampal plasticity may underlie the symptoms of depression and depressive-like behaviors, respectively. It is also possible that day length induces structural changes in human brains. Many seasonally breeding rodents undergo changes in whole brain and hippocampal volume in short days. Based on strict validity criteria, there is no animal model of SAD, but rodents that respond to reduced day lengths may be useful to approximate the neurobiological phenomena that occur in people with SAD, leading to greater understanding of the etiology of the disorder as well as novel therapeutic interventions.

[Longitudinal study comparing depressive female patients with and without premenstrual exacerbation]

INTRODUCTION

The aim of this study was to evaluate whether there are any differences in the clinical features of depression, personality and the G factor among women with and without premenstrual exacerbation (PE) of depression.

MATERIAL AND METHODS

Ninety-nine outpatients diagnosed with major depression (DSM-IV) were interviewed twice. At baseline, the patients were not taking medication. The 74 patients who achieved remission (Hamilton rating scale for depression ≤7) after 16 weeks were evaluated again through the 16-personality factor (16-PF) questionnaire (5(th) edition) and the D48 (or Dominos) test.

RESULTS

No differences in clinical characteristics or prognosis were found between the two groups of women, except for the greater presence of seasonal features among women with PE. Women with PE also scored higher for self-control on the 16-PF and scored lower on the D48 (Domino) test. The logistic analysis showed that higher self-control scores increased the risk for PE in 51.3% of the sample, while higher scores on the D48 test decreased the risk in 8.6%.

CONCLUSIONS

There were no differences between the two groups in the clinical features or prognosis of depression, except for the higher rates of seasonal features in the PE group. In contrast, differences were found in personality traits and the D48 between the two groups.

An overview of seasonal affective disorder and its treatment options

Seasonal affective disorder (SAD) is defined as a history of major depressive episodes that recur regularly at a particular time of year. Depending on the diagnostic instruments and criteria available, the reported prevalence (1%-10%) varies. Neurotransmitter abnormalities have been implicated in the pathophysiology, but they do not necessarily explain the seasonal pattern or the known chronobiological abnormalities in SAD compared with nonseasonal depression. Circadian rhythm abnormalies have been hypothesized to account for these aspects of SAD, and they provide a rationale for the therapeutic use of light therapy. Family history, twin, and molecular genetics studies suggest that hereditary factors are also involved. Light therapy and antidepressant medication are effective treatment options, with limited evidence for the efficacy of psychotherapy. Some studies demonstrate that narrow-band short wavelength "blue" light, naturalistic dawn simulation, and high-density negative air ionization are effective. Patients should be informed of the benefits of diet and exercise. Light therapy should be clinically monitored in the same manner, as it is done for other antidepressant treatments.

Binge eating, weight gain and psychosocial adjustment in patients with bipolar disorder

Binge Eating (BE) is a common eating pattern in patients with Bipolar Disorder (BD). BE may confer an increased risk for obesity, morbidity, mortality and poorer quality of life. We assessed the presence of BE and its impact on body weight, body image and self-esteem in 50 patients with BD and 50 age- and gender-matched controls. The presence and severity of BE was assessed with the Binge Eating Scale (BES). The Body Image and Self-Esteem Evaluation Scale (B-WISE) was used to assess the psychosocial impact of weight gain. Body Mass Index (BMI) was calculated. Nine (18%) patients had a score >27, indicating a likely diagnosis of BE. None of the control subjects had a BES score >17. No association between BES score and the medications was found. Patients had a significantly higher BES score, significantly higher BMI, waist circumference and fasting blood glucose. Although the B-Wise score was higher in the controls, the difference was not statistically significant. This study suggests that BE is prevalent in patients with BD. The presence of BE eating is a predictor of higher BMI, indicating that the disruption of eating behavior may be a pathway to weight gain.

Rat behavior after chronic variable stress and partial lesioning of 5-HT-ergic neurotransmission: effects of citalopram

Deficits in serotonergic (5-HT-ergic) neurotransmission and stressful life events have been implicated in affective disorders, and chronic variable stress (CVS) can elicit behavioral changes reminiscent of increased emotionality, anxiety and atypical depression after partial 5-HT depletion. This study examined the effect of chronic citalopram treatment (10 mg/kg daily) on these changes. Parachloroamphetamine (PCA) (2 mg/kg) reduced the levels of 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) in the frontal cortex, increased anxiety in the social interaction test, and increased activity in the open field. CVS reduced social activity in the social interaction test and immobility time in the forced swimming test. Reduction of excrements left during immobilization indicated partial adaptation with the CVS. Specific stressors had different effects on body weight gain, shorter lasting stressors having a smaller effect in general than those that lasted longer. Combination of CVS and PCA increased sucrose intake after two weeks of stress. In addition, combination of the two treatments reduced diving in the forced swimming test. Citalopram prevented the increase in sucrose consumption in the PCA+CVS rats, and in 5-HT-depleted animals blocked the increase in struggling and reduced the number of defecations in the forced swim test. In conclusion, citalopram treatment prevented several effects of either 5-HT depletion or combined PCA+CVS treatment, suggesting that these behavioral changes could be used in studies on the neural mechanisms underlying emotional behavior that may have relevance to the neurobiology of depression.

The psychobiology of burnout: are there two different syndromes?

BACKGROUND

Plasma prolactin levels are sensitive to dopamine and serotonin function, and fatigue. Low cortisol, dopamine and/or serotonin may be involved in burnout and detachment.

METHODS

In this double-blind within-subject study, we treated 9 female burnout subjects and 9 controls with 35 mg cortisol and placebo orally. We measured state affect and plasma prolactin, oxytocin, cortisol and adrenocorticotropic hormone levels, and administered an attachment questionnaire.

RESULTS

The burnout subjects displayed an extreme distribution of basal prolactin levels, displaying higher or lower levels compared to the controls. The low prolactin burnouts had profoundly low attachment scores and tended to have low oxytocin levels. The high prolactin burnout subjects tended to show cortisol-induced decreased prolactin and fatigue, and increased vigor.

CONCLUSION

Results are consistent with the hypothesis that burnout subjects are either characterized by low serotonergic function or by low dopaminergic function, and that the latter group benefits from cortisol replacement. These preliminary results suggest that differentiating between two syndromes may resolve inconsistencies in research on burnout, and be necessary for selecting the right treatment strategy.

Chocolate craving when depressed: a personality marker

We examined links between chocolate craving in people who are depressed and both personality style and atypical depressive symptoms, with a web-based questionnaire completed by nearly 3000 individuals reporting clinical depression. Chocolate was craved by half of the respondents (more so by women), judged as beneficial for depression, anxiety and irritability, and associated specifically with personality facets encompassed by the higher-order construct of neuroticism. The simple question of depression-associated chocolate craving appeared an efficient discriminator of DSM-IV atypical depression symptoms.

Isolating with physical restraint low status female monkeys during luteal phase might make an appropriate premenstrual depression syndrome model

BACKGROUND

Rhesus monkeys (Macaca mulatta) have a close phylogenetic relationship to humans, and have a similar 28-day menstrual cycle with similar hormonal fluctuations. In this study, we attempt to establish the premenstrual depression syndrome of rhesus monkey (M. mulatta) models by isolation with physical restraint of low social status young female monkeys during their luteal phase.

METHODS

Low social status young female rhesus monkeys (M. mulatta) were isolated with physical restraint during their luteal phase by using a specifically designed isolating-cage. During the entire menses cycle, serum levels of 5-hydroxytrypamine, noradrenalin and adrenalin were detected by capillary zone electrophoresis, and the changes in the serum levels of progesterone, estradiol and prolactin were investigated by radioimmunoassay. At the same time, the pharmaceutical interference effect of Jingqianshu granule, a traditional Chinese medicine specifically used to cure premenstrual depression patients, was tested using this premenstrual depression syndrome monkey model.

RESULTS

After being immured in two consecutive menstrual cycles, monkeys presented depressive symptoms during the premenstrual phase of three consecutive menstrual cycles. The serum contents of the three kinds of monoamine neurotransmitters in depressive monkeys were significantly higher than the normal ones. The serum levels of progesterone and prolactin increased obviously, and a marked change in the pattern of progesterone secretion could be observed. Moreover, the premenstrual depressive symptoms of model group monkeys could not only be cured by Jingqianshu granule, but the higher serum levels of prolactin and monoamine neurotransmitters in these monkeys could be reduced by this herbal medicine. These data were well in line with clinical observations of women with premenstrual depression syndrome.

CONCLUSION

Our results in this study for the first time indicate that isolation with physical restraint of low status young female monkeys during their luteal phase makes an appropriate premenstrual depression syndrome model. This model might potentially facilitate studies on the etiology of premenstrual depression syndrome and the development of better methods for the therapy of this disease.

Chocolate and women's sexual health: An intriguing correlation

INTRODUCTION

Historically chocolate has been reported to exert several effects on human sexuality, mainly acting as an effective aphrodisiac, increasing sexual desire, and improving sexual pleasure.

AIM

The aim of our study was to assess whether there is an association between daily chocolate intake and sexual function in a convenience sample of Northern Italian women.

METHODS

A convenience sample of 163 women (mean +/- SD age: 35.3 +/- 9.2 years; body mass index [BMI]: 22.5 +/- 3.5 kg/m2), recruited through advertising, completed an anonymous semistructured interview on recreational habits and questionnaires to assess sexual function (Female Sexual Function Index [FSFI]), sexual distress (Female Sexual Distress Scale), and depression (Beck Depression Inventory and Center for Epidemiological Survey Depression Scale).

RESULTS

Complete data were available for 153/163 (93.8%) women. Participants who reported daily chocolate intake (Group 1: 120 women) were significantly younger than those (Group 2: 33 women) who did not report to eat chocolate (33.9 +/- 0.8 years vs. 40.4 +/- 1.6 years, respectively) (P = 0.0003), despite a similar BMI. Participants in Group 1 had significantly higher total (P = 0.002) and desire domain (P = 0.01) FSFI scores than participants in Group 2. No differences between the two groups were observed concerning sexual arousal and satisfaction, sexual distress and depression. Our data also confirm that aging has a high statistically significant impact on women's sexual function.

CONCLUSIONS

It is alluring to hypothesize that chocolate can have either a psychological or a biological positive impact on women's sexuality. In our sample women reporting chocolate consumption have higher FSFI scores than women who do not eat chocolate. However, when data are adjusted for age FSFI scores are similar, regardless of chocolate consumption.

Mood state effects of chocolate

BACKGROUND

Chocolate consumption has long been associated with enjoyment and pleasure. Popular claims confer on chocolate the properties of being a stimulant, relaxant, euphoriant, aphrodisiac, tonic and antidepressant. The last claim stimulated this review.

METHOD

We review chocolate's properties and the principal hypotheses addressing its claimed mood altering propensities. We distinguish between food craving and emotional eating, consider their psycho-physiological underpinnings, and examine the likely 'positioning' of any effect of chocolate to each concept.

RESULTS

Chocolate can provide its own hedonistic reward by satisfying cravings but, when consumed as a comfort eating or emotional eating strategy, is more likely to be associated with prolongation rather than cessation of a dysphoric mood.

LIMITATIONS

This review focuses primarily on clarifying the possibility that, for some people, chocolate consumption may act as an antidepressant self-medication strategy and the processes by which this may occur.

CONCLUSIONS

Any mood benefits of chocolate consumption are ephemeral.

Role of familiarity on effects of caffeine- and glucose-containing soft drinks

Familiarity, through conditioned responses and expectations, may play a significant role in the expression of liking for, and mood and performance effects of, food and drink constituents. The role of familiarity and the effects of caffeine and glucose in Lucozade Energy were investigated by testing this familiar soft drink, and its non-caffeine/non-CHO placebo match, against novel coloured/flavoured full and placebo drinks. Both the familiar drink and its placebo improved alertness, mental energy and mental performance compared to baseline and compared to the novel placebo drink. After repeated exposure, that is, after having gained familiarity with the novel drinks in addition to the already existing familiarity with Lucozade Energy, only the full (caffeine and CHO containing) drinks showed sustained beneficial effects compared to placebo drinks and baseline measures, as well as an increase in liking compared to placebo drinks. Therefore, participants appeared to have learned that beneficial effects were mainly linked to the full products. The results illustrate the restorative combination of caffeine and CHO in the drink, and emphasises the need to implement the appropriate placebo(s) in any study design employing familiar foods or drinks.

Relationship between bipolar illness and binge-eating disorders

In this study we describe the frequency of eating disorders (EDs) in a group of bipolar (BP) patients. We evaluated a sample of 51 outpatients, diagnosed as having BP I disorder on the basis of the Structured Clinical Interview for DSM-IV (SCID). Each of these subjects was administered the Binge Eating Disorder Clinical Interview (BEDCI) to determine the presence of binge eating disorder (BED) or bulimia nervosa (BN). Of the 51 BP patients, 14 (9 BED, 5 BN) met criteria for an ED. Most patients developed binge eating coincident with the first episode of BP disorder or after the onset of it. This was true for those who developed BED as well as BN, and involved both manic and depressive phases. All BN patients were women (5/5), and family history of binge eating was present in 80% of BN subjects, but only in 22.2% of BED and 29.7% of non-ED BP patients. We found a high frequency of concordance between BP illness and binge eating problems in our sample of BP patients. Given the temporal sequence of the mood disorder, which generally preceded the ED, we suggest a model in which the ED evolves due to modulation of emotions with food, as well as use of medications to treat BP disorder that disrupt hunger and satiety mechanisms. Given differences in gender distribution and family history, cultural and familial influences may also be significant in the minority of BP binge-eating patients who develop BN.

Psychostimulant withdrawal as an inducing condition in animal models of depression

A large body of evidence indicates that the withdrawal from high doses of psychostimulant drugs in humans induces a transient syndrome, with symptoms that appear isomorphic to those of major depressive disorder. Pharmacological treatment strategies for psychostimulant withdrawal in humans have focused mainly on compounds with antidepressant properties. Animal models of psychostimulant withdrawal have been shown to demonstrate a wide range of deficits, including changes in homeostatic, affective and cognitive behaviors, as well as numerous physiological changes. Many of these behavioral and physiological sequelae parallel specific symptoms of major depressive disorder, and have been reversed by treatment with antidepressant drugs. These combined findings provide strong support for the use of psychostimulant withdrawal as an inducing condition in animal models of depression. In the current review we propound that the psychostimulant withdrawal model displays high levels of predictive and construct validity. Recent progress and limitations in the development of this model, as well as future directions for research, are evaluated and discussed.

Mood and cognitive performance effects of "energy" drink constituents: caffeine, glucose and carbonation

Three studies using healthy volunteers (n = 271) investigated the effects of caffeine, carbohydrates and carbonation in functional "energy" drinks (EDs) with the aim of determining their benefit in every-day life. The results showed caffeine to be the main ED constituent responsible for the effects found, with possible minor, relatively weak effects of carbohydrates. EDs were found to improve and/or maintain mood and performance during fatiguing and cognitively demanding tasks relative to placebo. In terms of absolute values, EDs maintained levels of arousal compared to a deterioration in arousal where placebo was consumed. These effects were found in caffeine-deprived participants, and so may be largely due to "withdrawal reversal". There were only minor differences in the effects of water vs. "sensory-matched" placebo, supporting previous findings indicating that the type of placebo does not alter the conclusions drawn about the effects of the full ED. Finally, carbonation had various effects on mood, some of which were present immediately following consumption, others were consistent with slower absorption of caffeine (and possibly carbohydrates) from carbonated drinks.

Chronic variable stress and partial 5-HT denervation by parachloroamphetamine treatment in the rat: effects on behavior and monoamine neurochemistry

Chronic variable stress (CVS) and manipulations of 5-HT-ergic neurotransmission are increasingly used as animal models of depression. In the present study, CVS for 2 weeks and a partial lesion of 5-HT projections by a small dose of parachloroamphetamine (PCA, 2 mg/kg) were applied independently or in combination. CVS reduced significantly the gain in body weight and increased the number of defecations in the open field test. PCA reduced body weight only within the first 24 h after its administration. Consumption of sucrose solution and its preference to water in non-deprived rats were significantly higher in PCA-pretreated rats 2 weeks after CVS compared to control animals. In the forced swimming test, both PCA and CVS treatments reduced immobility on the first but not the second session. Both treatments reduced significantly the time rats spent in social interaction. CVS also elicited an increase in the weight of the right adrenal, but this effect was not present in the PCA-pretreated group. PCA reduced 5-HT and 5-HIAA levels in the frontal cortex, hippocampus, and septum by approximately 20%. CVS increased HVA levels in the frontal cortex. Applied together, PCA pretreatment and CVS increased dopamine turnover in the frontal cortex. Conclusively, this study has provided evidence that chronic variable stress, which elicited expected physiological and neurochemical changes, does not reduce sucrose intake or preference in non-deprived animals, but, instead, may increase it after partial 5-HT-ergic denervation; and that partial 5-HT-ergic denervation by a low dose PCA treatment has a long-lasting effect on forced swimming and social behavior similar to chronic stress.

Food craving and food "addiction": a critical review of the evidence from a biopsychosocial perspective

Although certain commonalities exist between eating and drug use (mood effects, external cue-control of appetites, reinforcement, etc. ), it is argued that the vast majority of cases of (self-reported) food craving and food "addiction" should not be viewed as addictive behavior. An explanation is proposed that instead gives a prominent role to the psychological processes of ambivalence and attribution, operating together with normal mechanisms of appetite control, the hedonic effects of certain foods, and socially and culturally determined perceptions of appropriate intakes and uses of those foods. Ambivalence (e.g., "nice but naughty") about foods such as chocolate arises from the attitude that it is highly palatable but should be eaten with restraint. Attempts to restrict intake, however, cause the desire for chocolate to become more salient, an experience that is then labelled as a craving. This, together with a need to provide a reason for why resisting eating chocolate is difficult and sometimes fails, can, in turn, lead the individual to an explanation in terms of addiction (e.g., "chocoholism"). Moreishness ("causing a desire for more") occurs during, rather than preceding, an eating episode, and is experienced when the eater attempts to limit consumption before appetite for the food has been sated.

Mood correlates with blood serotonin, but not with glucose measures in patients with recurrent suicidal behavior

Depressive mood and impulsive-aggressive behavior are relevant to suicidal behavior and have been associated with decreased central serotonergic function. Impulsive behavior and aggression have also been related to abnormal glucose metabolism. To investigate these relationships further, blood serotonin (5-HT), blood glucose measures (glycated hemoglobin (HbA1C) and fructosamine) and self-reported depressive symptoms and anger were repeatedly measured, during a 1-year follow-up, in 106 patients who had recently attempted suicide for at least a second time. A major DSM-III-R Axis I diagnosis or use of antidepressants were reasons for exclusion. Intra-individual variations in blood 5-HT were inversely correlated with variations in depressive mood, self-depreciation, and anger, and positively with variations in fructosamine. Intra-individual variations of HbA1c or fructosamine were not correlated with mood. Mean blood 5-HT levels per patient were positively correlated with mean scores of depression and self-depreciation. The contrast between the intra-individual and the inter-individual correlations may reflect a difference between short- vs. long-term effects. The results do support an association between serotonergic function and mood, but not between glucose metabolism and mood, in recurrent suicide attempters.

Low central nervous system serotonergic activity is traitlike and correlates with impulsive behavior. A nonhuman primate model investigating genetic and environmental influences on neurotransmission

We have used nonhuman primates to examine developmental and behavioral correlates of CNS serotonergic activity, as measured by concentrations of the serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) in the cerebrospinal fluid (CSF). These studies show that interindividual differences in CNS serotonin turnover rate exhibit traitlike qualities and are stable across time and settings, with interindividual differences in CSF 5-HIAA concentrations showing positive correlations across repeated sampling. Primates with low CNS serotonergic activity exhibit behaviors indicative of impaired impulse control, unrestrained aggression, social isolation, and low social dominance. Maternal and paternal genetic influences play major roles in producing low CNS serotonin functioning, beginning early in life. These genetic influences on serotonin functioning are further influenced by early rearing experiences, particularly parental deprivation.

Women, food, and mood

Associations between food intake and mood greatly interest both lay and scientific audiences, although scientific support for many observed associations is sparse. Of particular interest are issues surrounding food intake, food cravings, and mood in women throughout the menstrual cycle. Further research is necessary to support or disprove current hypotheses about the relationship between food intake and mood. Meanwhile, health professionals should be prepared to inform the public about the complexity of factors that influence the relationship between food intake and mood.

Serotonin and gender-specific psychiatric disorders

The serotonergic system has been linked to the etiology of several, albeit disparate, psychiatric disorders. The accumulation of many lines of evidence support the view that there are gender differences in the serotonergic system in humans. It is further proposed that a gender differentiated serotonergic system acts as the nidus for the development of gender-specific psychiatric disorders. Depression, anxiety and eating disorders are largely seen in females, whereas alcoholism, aggressivity and suicide predominate in males. Evidence from both animal and human studies suggesting that the serotonergic system mediates between social-environmental experience and biological states is presented and reviewed. A reconceptualization of the serotonergic system as a gender-specific psychobiological interface is proposed. (Int J Psych Clin Prac 1997; 1: 3-13).

A nonhuman primate model of type II excessive alcohol consumption? Part 1. Low cerebrospinal fluid 5-hydroxyindoleacetic acid concentrations and diminished social competence correlate with excessive alcohol consumption

Developmental, biochemical, and behavioral concomitants of excessive alcohol consumption were investigated using a nonhuman primate model. The variables of interest were: (1) interindividual stability of cerebrospinal fluid (CSF) 5-hydroxyindoleacetic acid (5-HIAA) from infancy to adulthood, (2) effect of parental deprivation early in life on adult CSF 5-HIAA concentrations; (3) correlations between CSF 5-HIAA and 3-methoxy-4-hydroxyphenylglycol (MHPG) concentrations and alcohol consumption; and (4) correlation between the frequency of competent social behaviors and alcohol consumption. Twenty-nine rhesus macaques were reared for their first 6 months either with their mothers or without adults in peer-only conditions. At 6 and 50 months of age, each subject underwent a series of four, 4-day social separations. Cisternal CSF was sampled before and during the first and last separations; concomitantly, observational data were collected on social dominance behavior in the home-cage. When they reached 50 months of age, the monkeys were provided free access to a palatable alcohol solution daily for 1-hr periods before, during, and after the social separations. Before and after the 50-month separations, data were collected on all types of social behavior in the home-cage. Results showed that peer-reared subjects consumed more alcohol than mother-reared subjects during baseline conditions. Mother-reared subjects, however, increased their rates of consumption to equal peer-reared subjects' rates of consumption during the conditions of a social separation stressor. Peer-reared subjects also exhibited lower CSF 5-HIAA concentrations in infancy and adulthood than their mother-reared counterparts. With rearing condition held constant, interindividual differences in CSF 5-HIAA, MHPG, and homovanillic acid were stable from infancy to adulthood, and high rates of alcohol were consumed by the young adult monkeys with low CSF 5-HIAA and MHPG concentrations, particularly when the CSF was obtained during the social separations. High rates of alcohol consumption were also observed in subjects with infrequent social interactions and less competent social behaviors. In contrast to the human data, we found no gender differences in rates of alcohol consumption, nor in the correlations between alcohol consumption and the other variables. With some exceptions, findings from the study are generally consistent with predictions from Cloninger's type II model of excessive alcohol consumption in men with low CSF 5-HIAA, who also exhibit impaired impulse control and violent and antisocial behaviors.

Beyond specificity: effects of serotonin and serotonergic treatments on psychobiological dysfunction

Serotonin is a ubiquitous neurotransmitter with widespread projections that provide for the involvement of serotonin in the regulation of many biological and psychological functions. A variety of serotonin receptor subtypes exist that mediate overlapping psychobiological functions and that are targets for a new generation of medications. Although these new generation medications appear to possess great biochemical specificity, their actions extend to many psychiatric disorders, reflecting the many interactions of serotonergic subsystems.

[The effect of tryptophan on the regulation of food intake in normal and overweight persons]

The neurotransmitter serotonin significantly contributes to the regulation of food intake and appetite behaviour. The cerebral serotonin synthesis depends on the availability of the precursor tryptophan. To examine how diets with different carbohydrate, protein and tryptophan content affect food preferences and the mood, healthy obese and non-obese male adults consumed the following isocaloric diets at breakfast: standard diet (60% carbohydrate), protein-rich diet (35% carbohydrate, 40% protein), carbohydrate-rich diet (80% carbohydrate), tryptophan supplemented diet (standard diet + 1.5 g tryptophan). The plasma concentration of tryptophan (TRP) and large neutral amino acids (LNAA) is determined by their uptake with the diet. In obese and non-obese adults the TRP/LNAA-quotient rose significantly by upto 0.40 to 0.57, following the tryptophan supplemented breakfast. The protein-rich diet reduced the TRP/LNAA-quotient. The preference of protein-rich food after the consumption of carbohydrate-rich diets (60-80% carbohydrate) was diagnosable with the non-obese person and not with the obese person. No obvious connection was detected between nutrient preferences and plasma TRP/LNAA-quotient. There was no influence of the plasma TRP/LNAA-quotient after meals with different nutrient relation on mood. Therefore it is concluded that different carbohydrate and protein content and also additional tryptophan supplementation of single meals is not able to modify the brain serotonin synthesis and release in healthy people in a kind that serotonin induced behaviour would be changed, at least on a short time basis.