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Journal Article 2013; 34(1): 1-8 PubMed PMID: 23524617 Citation  Keywords:  Bipolar Disorder:epidemiology, Comorbidity, Exploratory Behavior, Humans, Personality Disorders:epidemiology, Reward, Substance-Related Disorders:epidemiology,.   

BACKGROUND: Outcome in bipolar patients can be affected by comorbidity of other psychiatric disorders. Comorbid personality disorders are frequent and may complicate the course of bipolar illness. We have much information about treating patients with uncomplicated bipolar disorder (BD) but much less knowledge about possibilities for patients with the comorbidity of BD and personality disorder.

METHOD: We conducted a series of literature searches using, as key words or as items in indexed fields, bipolar disorder and personality disorder or personality traits. Articles were obtained by searching MEDLINE from 1970 to 2012. In addition, we used other papers cited in articles from these searches, or cited in articles used in our own work.

RESULTS: Tests of personality traits indicated that euthymic bipolar patients have higher scores on harm avoidance, reward dependence, and novelty seeking than controls. Elevation of novelty seeking in bipolar patients is associated with substance abuse comorbidity.

CONCLUSION: Comorbidity with personality disorders in BD patients is associated with a more difficult course of illness (such as longer episodes, shorter time euthymic, and earlier age at onset) and an increase in comorbid substance abuse, suicidality and aggression. These problems are particularly pronounced in comorbidity with borderline personality disorder. Comorbidity with antisocial personality disorder elicits a similar spectrum of difficulties; some of the antisocial behavior exhibited by patients with this comorbidity is mediated by increased impulsivity....

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Comparative Study 2010; 31(5): 616-621 PubMed PMID: 21178944 Citation  Keywords:  Adult, Aged, Choice Behavior, Corticosterone:secretion, Female, Follow-Up Studies, Humans, Hydrocortisone:secretion, Impulsive Behavior:metabolism, Individuality, Male, Mass Spectrometry, Middle Aged, Models, Psychological, Reward, Saliva:metabolism, Sex .   

OBJECTIVES: Stress hormones have been associated with temporal discounting. Although time-discount rate is shown to be stable over a long term, no study to date examines whether individual differences in stress hormones could predict individuals' time-discount rates in the relatively distant future (e.g., six month later), which is of interest in neuroeconomics of stress-addiction association.

METHODS: We assessed 87 participants' salivary stress hormone (cortisol, cortisone, and alpha-amylase) levels and hyperbolic discounting of delayed rewards consisting of three magnitudes, at the time-interval of six months. For salivary steroid assays, we employed a liquid chromatography/ mass spectroscopy (LC/MS) method. The correlations between the stress hormone levels and time-discount rates were examined.

RESULTS: We observed that salivary alpha-amylase (sAA) levels were negatively associated with time-discount rates in never-smokers. Notably, salivary levels of stress steroids (i.e., cortisol and cortisone) negatively and positively related to time-discount rates in men and women, respectively, in never-smokers. Ever-smokers' discount rates were not predicted from these stress hormone levels.

CONCLUSIONS: Individual differences in stress hormone levels predict impulsivity in temporal discounting in the future. There are sex differences in the effect of stress steroids on temporal discounting; while there was no sex defference in the relationship between sAA and temporal discounting....

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Journal Article 2010; 31(1): 122-125 PubMed PMID: 20150884 Citation  Keywords:  Adolescent, Adult, Autistic Disorder:blood, Case-Control Studies, Emotions:physiology, Female, Humans, Lymphocytes:metabolism, Male, Music, RNA, Messenger:metabolism, Receptors, Dopamine D3:genetics, Receptors, Dopamine D4:genetics, Reward, Up-Regulation:.   

BACKGROUND: People with autistic spectrum disorder (ASD) are affected by a long-life disabling condition, characterized by communication deficits, severe impairments in social functioning, and stereotyped behaviors. Although ASD individuals display several problems in interactions, it has been reported that they may show a peculiar interest in music. Previous studies have suggested a pivotal role for the dopaminergic system in the psychobiology of reward, including the pleasure of music.

DESIGN: In the present study, we sought to investigate dopamine DRD3 and DRD4 receptor expression in peripheral blood lymphocytes of adult healthy musicians and age- and gender-matched patients with ASD against the background hypothesis that the dopaminergic system may contribute a biological cause to the reward dimensions of the musical experience in both healthy and autistic individuals.

RESULTS: ANOVA showed significant differences in DRD4 mRNA expression between the groups (P = 0.008). Post-hoc analysis showed significant differences between the control group and both musicians (P < 0.05) and ASD individuals (P < 0.05). No differences were found for DRD3 mRNA expression between the groups.

CONCLUSION: Our current results provide intriguing preliminary evidence for a possible molecular link between dopamine DRD4 receptor, music and autism, possibly via mechanisms involving the reward system and the appraisal of emotions....

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Journal Article 2008; 29(4): 451-453 PubMed PMID: 18766143 Citation  Keywords:  Humans, Impulsive Behavior, Male, Neuroendocrinology, Reward, Saliva:enzymology, Statistics as Topic, Surveys and Questionnaires, alpha-Amylases:metabolism,.   

OBJECTIVES: This study was aimed to examine the relationships between salivary alpha-amylase (sAA, a non-invasive biological marker of adrenergic activities) levels and hyperbolic discounting for primary reward under simulated life-threatening condition, which is of interest in psychoneuroendocrinology and neuroeconomics of visceral influences on behavior.

METHODS: We assessed degrees to which delayed primary reward (i.e., water) was discounted (hyperbolic discount rates) in 31 healthy male students. Participants' sAA were also assessed.

RESULTS: We observed a positive correlation between sAA and hyperbolic discounting for primary reward.

CONCLUSIONS: The result indicates that threat-induced visceral urge acutely prompts impulsivity in temporal discounting....

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Journal Article 2008; 29(3): 351-358 PubMed PMID: 18580849 Citation  Keywords:  Adult, Aged, Choice Behavior:physiology, Data Interpretation, Statistical, Depressive Disorder:psychology, Economics, Female, Humans, Impulsive Behavior:psychology, Male, Middle Aged, Neuropsychological Tests, Psychiatric Status Rating Scales, Reward, Ser.   

OBJECTIVES: Depression has been associated with impaired neural processing of reward and punishment. However, to date, little is known regarding the relationship between depression and intertemporal choice (delay discounting) for gain and loss. This examination is potentially important for advances in neuroeconomics of intertemporal choice, because depression is associated with reduced serotonergic activities in the brain.

DESIGN AND SETTING: We compared impulsivity and inconsistency in intertemporal choice for monetary gain and loss between depressive patients and healthy control subjects.

METHODS: We conducted delay discounting tasks for gain and loss in depressed and healthy control subjects. We then quantified impulsivity and inconsistency in the delay discounting with parameters in the q-exponential discount function based on Tsallis' statistics.

RESULTS: We observed that depressive patients were more impulsive and time-inconsistent in intertemporal choice action for gain and loss, in comparison to healthy controls.

MAIN FINDINGS: Depressed patients were more irrational in temporal discounting.

CONCLUSIONS: The usefulness of the q-exponential discount function for assessing the impaired decision-making by depressive patients was demonstrated. Furthermore, biophysical mechanisms underlying the altered intertemporal choice by depressive patients are discussed in relation to impaired serotonergic neural systems....

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Journal Article 2007; 28(5): 662-665 PubMed PMID: 17984929 Citation  Keywords:  Adolescent, Adult, Altruism, Amylases:metabolism, Decision Making:physiology, Games, Experimental, Humans, Male, Reference Values, Reward, Saliva:metabolism, Self Concept, Social Perception,.   

OBJECTIVE: Little is known regarding the relationship between social evaluation-induced neuroendocrine responses and generosity in game-theoretic situations. Previous studies demonstrated that reputation formation plays a pivotal role in prosocial behavior. This study aimed to examine the relationships between a social evaluation-induced salivary alpha-amylase (sAA) response and generosity in the dictator game. The relationship is potentially important in neuroeconomics of altruism and game theory.

METHODS: We assessed sAA and allocated money in the dictator game in male students with and without social evaluation. RESULTS Social evaluation-responders allocated significantly more money than controls; while there was no significant correlation between social evaluation-induced sAA elevation and the allocated money.

CONCLUSIONS: Social evaluation significantly increases generosity in the dictator game, and individual differences in trait characteristics such as altruism and reward sensitivity may be important determinants of generosity in the dictator game task....

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Journal Article 2007; 28(2): 131-136 PubMed PMID: 17435675 Citation  Keywords:  Alcoholism:prevention & control, Choice Behavior:physiology, Humans, Impulsive Behavior:etiology, Inpatients, Male, Middle Aged, Reward, Time Factors,.   

OBJECTIVES: Alcohol dependence has been associated with disrupted neuroendocrine systems, impulsivity in intertemporal choice (delay discounting). However, little is known regarding stability of discount rates in alcoholics. This study examined both differential stability (stability of individual differences) and absolute stability (stability of group mean) of hyperbolic discount rates for monetary gains in severe alcoholic inpatients (diagnosed with DSM-IV) over a 2-month period during abstinence.

METHODS: We estimated male alcoholics' discount rates for delayed monetary rewards on the basis of their pattern of choices between smaller immediate rewards (1,100-8,000 yen) and larger, delayed rewards (2,500-8,500 yen; at delays from 1 week to 6 months), two times at 2-month time-interval during hospitalized alcohol withdrawal.

RESULTS: It was observed that the alcoholics' mean hyperbolic discount rates for gains had both differential and absolute stability over 2 months, although a slight non-significant decrease in the group mean of the discount rates was observed.

CONCLUSIONS: The results indicate that abstinent alcoholic's discount rates are stable over a relatively long-term period. The usefulness of assessing discount rates of addicts in psychoneuroendocrinology and neuroeconomics of addiction is discussed....

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Journal Article 2006; 27(1-2): 21-33 PubMed PMID: 16648819 Citation  Keywords:  Diet, Eating:psychology, Food, Humans, Motivation, Receptors, Opioid, mu:physiology, Reward, Satiety Response:physiology,.   

: Over the last decades, the importance of food in the development of chronic diseases has been examined, as well as the medical value of eating healthy. The contribution of the eating process itself to health and well-being, however, has not been questioned until most recently. Biology has linked eating to appetitive motivational processes with their underlying neurophysiology, including CNS reward circuitries: Eating uses the pleasure-reward physiology to motivate us to eat. Endogenous opiates, such as morphine, insure our survival by helping us to make eating motivational via pleasure induction. After taking in enough food, we become satisfied, i.e., tolerant to food. Our appetite, and so is our appetence, are then low and need a certain time span to reach their former levels for then inducing food-seeking behaviors, food intake, etc. again. When tolerance passes, we once more engage in this pleasurable process related to positive behavioral motivation. Opioid receptor agonists, however, may induce energy intake even beyond an actual need. This interesting potential of opioidergic signaling may have its roots in biological mechanisms that insured the intake and storage of high energy foods, hence preparing for future famines. In our world of today, however, such neurobiological pathways may pose a threat on our health. Thus, feedback mechanisms, such as tolerance, aversion and satiety, have to be finely tuned. Therefore central autoregulation that involves, for example, limbic mu receptor signaling and other endogenous signaling compounds comes into the focus of modern science. The time where research recognizes the importance of neurobiological pathways such as endogenous opiate autoregulation or CNS reward circuitries for examining the physiology of food intake has yet begun. Many questions remain open and have to be answered through future scientific inquiry....

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