Pleasant Stimuli Research Articles

The effect of ketamine on affective modulation of the startle reflex and its resting-state brain correlates

Ketamine is a rapid-acting antidepressant that also influences neural reactivity to affective stimuli. However, the effect of ketamine on behavioral affective reactivity is yet to be elucidated. The affect-modulated startle reflex paradigm (AMSR) allows examining the valence-specific aspects of behavioral affective reactivity. We hypothesized that ketamine alters the modulation of the startle reflex during processing of unpleasant and pleasant stimuli and weakens the resting-state functional connectivity (rsFC) within the modulatory pathway, namely between the centromedial nucleus of the amygdala and nucleus reticularis pontis caudalis. In a randomized, double-blind, placebo-controlled, cross-over study, thirty-two healthy male participants underwent ultra-high field resting-state functional magnetic resonance imaging at 7 T before and 24 h after placebo and S-ketamine infusions. Participants completed the AMSR task at baseline and one day after each infusion. In contrast to our hypothesis, ketamine infusion did not impact startle potentiation during processing of unpleasant stimuli but resulted in diminished startle attenuation during processing of pleasant stimuli. This diminishment significantly correlated with end-of-infusion plasma levels of ketamine and norketamine. Furthermore, ketamine induced a decrease in rsFC within the modulatory startle reflex pathway. The results of this first study on the effect of ketamine on the AMSR suggest that ketamine might attenuate the motivational significance of pleasant stimuli in healthy participants one day after infusion.

Exploring the relationship between emotion regulation, inhibitory control, and eating psychopathology in a non-clinical sample.

The present study aimed to explore the relationship between difficulties in emotion regulation and deficits in inhibitory control, and the role of these processes in eating psychopathology in a non-clinical sample. We also explored the specificity in which deficits in inhibitory control may underlie eating psychopathology, namely whether they can be conceptualised as context specific or more extensive in nature. Participants were 107 healthy individuals recruited at a major Portuguese university, aged between 18 and 43years-old (M=21.23, SD=4.79). Two computerised neuropsychological tasks (i.e., emotional go/no-go and food go/no-go tasks) were used to assess response inhibition in the presence of general versus context-specific stimuli. A set of self-report measures was used to assess variables of interest such as emotion regulation and eating psychopathology. Results indicated higher response inhibition deficits among participants with higher difficulties in emotion regulation comparing to those with lower difficulties in emotion regulation, particularly in the context of food-related stimuli. In addition, the relationship between difficulties in emotion regulation and eating psychopathology was moderated by inhibitory control deficits in both the context of food and pleasant stimuli. The present findings highlight inhibitory control as an important process underlying the relationship between difficulties in emotion regulation and eating psychopathology in non-clinical samples. Findings have important implications for clinical practice and the prevention of eating psychopathology in healthy individuals and individuals with eating disorders.

Choosing to avoid the positive? Emotion regulation strategy choice in depression.

Individuals with major depressive disorder (MDD) are more likely than nondepressed individuals to use emotion regulation strategies that decrease pleasant emotions (e.g., distraction from positive stimuli) and increase unpleasant emotions (e.g., negative rumination). If such strategies are actively chosen, these choices may partly reflect weaker motivation for pleasant emotions or stronger motivation for unpleasant emotions. Therefore, this investigation tested, for the first time, whether such strategies are actively chosen, even when alternatives are available. In Study 1, using a behavioral task, MDD participants (N = 38) were more likely than healthy controls (N = 39) to choose to use distraction over positive rumination in response to pleasant stimuli, resulting in reductions in pleasant affect. When instructed to choose the strategy that would make them feel better, however, MDD participants did not differ from controls in their strategy choices. In Study 2, using ecological momentary assessments, MDD participants (N = 58) were more likely than controls (N = 62) to use distraction from pleasant emotions and to use negative rumination in daily life. This pattern of strategy use was predicted by stronger motivation for unpleasant emotions among MDD participants, compared to controls. Stronger motivation for unpleasant emotions in daily life also predicted increases in unpleasant affect and decreases in pleasant affect. Findings suggest that compared to nondepressed individuals, people with MDD are more likely to choose emotion regulation strategies that decrease pleasant emotions. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Physical activity, music and the aging brain - A Review

The COVID-19 pandemic is a global health crisis with physical and mental disorders, especially for the elderly. Resilience or the ability to bounce back or recover from stress and negative emotions are important for well-being. Music is a powerful, pleasurable stimulus that can induce positive well-being and promoting cognition. A combination of non-pharmaceutical interventions can produce more benefits. Several studies support the notion that physical activity can help alleviate the negative impact of age on body and mind. Research on normal and pathological aging reveal that music is an interesting and powerful means of promoting cognition, well-being and social connection in older adults. Physical exercise combined with music induces greater positive effects on cognition function, well-being and lead to neuroanatomical changes. Music and exercise cross the disciplines of bio-mechanics, neurology, physiology and sport psychology and bring social and spiritual benefits. Self-selected music elicited the greatest improvements, it offers a motivational boost, resulting in greater enjoyment and longer engagement in activity. This literature review aims to provide an overview on studies that have explored physical activity and the aging brain. And how music combined with physical activity can positively have an impact on emotional well-being of the elderly.
 Keywords: Music, Exercises, Well-being, Aging Brain

Triarchic psychopathy and affective picture processing: An event-related potential study

Psychopathy and its precursors appear to be associated with abnormal affective response. For example, individuals high in psychopathy show reduced psychophysiological response to unpleasant stimuli, which might explain low levels of empathy in psychopathic individuals, and their pursuit of individual goals without regard for others’ wellbeing. In keeping with the notion that psychopathology is best represented on a continuum, the triarchic model suggests that psychopathy is characterized by elevations on three traits: boldness, meanness and disinhibition. Understanding how these traits relate to psychophysiological response to emotional stimuli would help validate the triarchic model, while also bridging to other psychopathological spectra (e.g., internalizing psychopathology, which is characterized by low boldness). Here, N = 123 young adults passively viewed unpleasant, pleasant and neutral pictures while subjective and electrocortical response were recorded. Controlling for the other triarchic traits, individuals with higher self-reported meanness had smaller late positive potentials (LPPs) to both pleasant and unpleasant pictures, whereas individuals higher in boldness had larger LPPs to unpleasant pictures. In addition, those higher in meanness rated unpleasant pictures as more pleasant and less emotionally arousing. Disinhibition was not associated with the LPP or ratings. Meanness appears to drive blunted response to unpleasant pictures that has previously been observed among those high on psychopathy, and may also be associated with reduced engagement with generic pleasant stimuli. Moreover, results converge with prior work on other traits of transdiagnostic relevance (e.g., extraversion), as well as internalizing symptoms, providing a bridge between psychopathy and other forms of psychopathology.

Emotional processing and positive affect after acute exercise in healthy older adults.

The well-elucidated improvement of mood immediately after exercise in older adults presumably involves adaptations in emotion-processing brain networks. However, little is known about effects of acute exercise on appetitive and aversive emotion-related network recruitment in older adults. The purpose of this study was to determine the effect of acute exercise, compared to a seated rest control condition, on pleasant and unpleasant emotion-related regional activation in healthy older adults. Functional MRI data were acquired from 32 active older adults during blocked presentations of pleasant, neutral and unpleasant images from the International Affective Pictures System. fMRI data were collected after participants completed 30 min of moderate to vigorous intensity cycling or seated rest, performed in a counterbalanced order across separate days in a within-subject design. The findings suggest three ways that emotional processing in the brain may be different immediately after exercise (relative to immediately after rest): First, reduced demands on emotional regulation during pleasant emotional processing as indicated by lower precuneus activation for pleasant stimuli; second, reduced processing of negative emotional stimuli in visual association areas as indicated by lower activation for unpleasant stimuli in the bilateral fusiform and ITG; third, an increased recruitment in activation associated with regulating/inhibiting unpleasant emotional processing in the bilateral medial superior frontal gyrus (dorsomedial prefrontal cortex), angular gyri, supramarginal gyri, left cerebellar crus I/II and a portion of right dorsolateral prefrontal cortex. Overall, these findings support that acute exercise in active older adults alters activation in key emotional processing and regulating brain regions.

Contextual processing and its alterations in patients with addictive disorders

Contextual processing is implicated in the pathophysiology of addictive disorders, but the nature of putative deficiencies remains unclear. We assessed some aspects of contextual processing across multimodal experimental procedures with detoxified subjects who were dependent on opioids (n = 18), alcohol- (n = 20), both opioids and alcohol (n = 22) and healthy controls (n = 24) using a) facial- and b) emotionally laden images; c) gambling task and d) sucrose solutions. Healthy subjects displayed consistent response pattern throughout all categories of the presented stimuli. As a group, dependent subjects rated (i.e., valuated) attractive and average faces respectively more and less attractive in comparison to controls. Dependent subjects' motivational effort, measured in the units of computer keypress to determine the attractive faces' viewing time, accorded the valuational context but was diminished relatively to the average faces’ valuation. Dependent subjects’ motivational effort for pleasant and aversive images respectively mirrored the attractive and average faces; their neutral images’ motivational effort was incongruent with the valuational context framed by the intermixed images. Also, dependent subjects’ emotional responses to counterfactual comparisons of gambling outcomes were unmatched by the riskiness context. Moreover, dependent subjects failed to show greater liking of sweet solutions that normally accompanies low sweetness perceptual context indicative of higher sucrose concentration needed for maximal hedonic experience. Consistent differences among the dependent groups (opioid vs. alcohol vs. comorbid) on the above procedures were not observed. The present findings suggest that opioid and/or alcohol dependence may be associated with amplified hedonic and motivational valuation of pleasant stimuli and with a disrupted link between behavioral/emotional responsivity and contextual variations. Further research is warranted to unravel the distinctive features of contextual processing in opioid- vis-à-vis alcohol addiction and how these features may interrelate in comorbid conditions.

Associations between resting-state neural connectivity and positive affect in social anxiety disorder.

Social anxiety disorder (SAD) has been characterized by deficits in social motivation and lack of reactivity to pleasurable stimuli (i.e., positive affect; [PA]). Recent neuroimaging work has shifted toward examining positively valenced motivational systems in SAD focused on reward responses. However, little is known about the associations of reward connectivity and PA in individuals with SAD. As such, the purpose of the current study was to determine whether connectivity among key units of reward neurocircuitry meaningfully relate to PA and whether these key units are more heterogeneous in SAD as compared to controls. Thirty-one participants who met diagnostic criteria for SAD and 33 control participants were included (Mage = 24.8, SD = 6.9; 55% cisgender man). Seed-based timeseries correlations were conducted in NiTime to extract region of interest (ROI) coupling correlation strength values. ANOVAs were carried out to assess whether individuals with SAD differed in ROI-to-ROI connectivity strength as compared to controls. Correlations and variance analyses were also conducted to examine the relationship between ROI-to-ROI connectivity strength and PA, as well as heterogeneity in connectivity strength and PA expression. Weaker connectivity between the left and right orbital frontal cortex was observed when comparing the SAD to the control group. Within the SAD group, PA was associated with several reward-related ROI couplings; however, these links were not observed among controls. Results further demonstrated that individuals with SAD had significantly more variability in reward connectivity strength as compared to controls. Overall, these results provide emergent evidence for the association between reward regions and PA in individuals with SAD. Additionally, these findings show that individuals with SAD demonstrate greater heterogeneity in reward connectivity.

The riddle of deliberate self-harm: Physiological and subjective effects of self-cutting cues in patients with borderline personality disorder and healthy controls.

Self-harming behavior is a core symptom of borderline personality disorder. Self-report studies show a correlation between a lack of self-reported negative feelings toward self-cutting cues and the likelihood of future self-destructive behavior. Despite these findings, there has so far been insufficient investigation into the implicit emotional processes evoked by this stimulus type. Forty patients with borderline personality disorder and 35 healthy controls between 20 and 50 years of age were confronted with pictures of self-cutting cues and affective reference pictures. A startle reflex paradigm was used for measuring implicit emotional responses, and the Self-Assessment Manikin was used for subjective responses. In line with previous studies, the patients rated the self-cutting pictures significantly less negatively than healthy individuals. On the physiological level, a significant startle inhibition was observed, indicating an activation of the behavioral approach system. A more detailed analysis showed that this startle inhibition effect was specific to scary pictures, whereas no such effect was observed for bloody wounds and self-cutting instruments. For pleasant standard pictures, in contrast, no startle reflex inhibition and no increase in emotional arousal parameters were found. The data replicate the findings of previous studies, demonstrating a generally diminished emotional reactivity to pleasant stimuli in patients with borderline personality disorder. In addition, a physiological approach reaction to self-cutting pictures was found, especially for the scary pictures. These results might indicate a positive identification with the long-lasting consequences of self-cutting behavior in the patients. Implications for therapy are discussed.

Neuroaffective reactivity profiles are associated with vulnerability to e-cigarette use

BackgroundWe tested whether neuroaffective responses to motivationally salient stimuli are associated with vulnerability to cue-induced e-cigarette use in e-cigarette naïve adults who smoke daily. We hypothesized that individuals with stronger neuroaffective responses to nicotine-related cues than to pleasant stimuli (the C>P reactivity profile) would be more vulnerable to cue-induced nicotine self-administration than individuals with stronger neuroaffective responses to pleasant stimuli than to nicotine-related cues (the P>C reactivity profile). MethodsWe used event-related potentials (ERPs, a direct measure of cortical activity) to measure neuroaffective reactivity to pleasant, unpleasant, neutral, and nicotine-related cues indicating the opportunity to use an e-cigarette in 36 participants. For each picture category, we computed the amplitude of the late positive potential (LPP), a robust index of motivational salience. To identify each individual’s neuroaffective reactivity profile we applied k-means cluster analysis on the LPP responses. We compared the e-cigarette use frequency across profiles using quantile regression for counts. ResultsK-means cluster analysis assigned 18 participants to the C>P profile and 18 participants to the P>C profile. Individuals with the C>P neuroaffective profile used the e-cigarette significantly more often than those with the P>C profile. Significant differences in the number of puffs persisted across different quantiles. ConclusionsThese results support the hypothesis that individual differences in the tendency to attribute motivational salience to drug-related cues underlie vulnerability to cue-induced drug self-administration. Targeting the neuroaffective profiles that we identified with tailored treatments could improve clinical outcomes.

The multimodal emotion perception in codependent individuals

The emotional disturbances of individuals with codependency are often ignored. This study aimed to investigate the emotional perception of codependent individuals in four modalities – visual, auditory, tactile and olfactory. An EEG study was performed and presented pleasant and unpleasant stimuli selected by a panel of experts for each modality. Participants (fifteen codependent individuals and fifteen healthy volunteers) were instructed to assess the emotional impact and pleasantness of stimuli. The method of EEG spaces was used to visualize how close perceived stimuli were according to EEG data. The results showed ambivalence of emotional response to emotional stimuli with social component and lack of recognition of emotional tone detected in EEG and behavioral levels. The empathy feeling in codependent individuals was detected for fewer emotional stimuli. The group differences were associated with evolutionary newer modalities (auditory and visual). The lack of emotional perception in codependent subjects was determined by social factors and was detected in visual and auditory modalities, which were more involved in social interactions than olfactory and tactile modalities.

Does partial blockade of dopamine D2 receptors with Amisulpride cause anhedonia? An experimental study in healthy volunteers

BackgroundAnhedonia is a frequent cause of functional impairment in psychosis. Although it is plausible that medication-induced D2 receptor blockade could diminish hedonic responding, there is little experimental research testing this hypothesis in humans. MethodsTo inspect possible effects of partial D2 blockade on hedonic experiences, we administered 300 mg of Amisulpride or placebo to 85 participants in a randomized, double-blind, placebo-controlled trial. Participants were then subjected to an emotional evocation task utilizing standardized pictorial pleasant, neutral, and unpleasant stimuli. ResultsWe observed lower positivity ratings in the Amisulpride group compared to placebo across all stimulus categories (p = .026, f = 0.25) and no group differences in negativity or arousal ratings. The Amisulpride group also showed lower electrodermal responses across all stimulus categories compared to placebo (p = .017, f = 0.27). The electrodermal response was especially diminished for pleasant stimuli. ConclusionWe interpret our findings as evidence that D2 blockade via Amisulpride can reduce at-the-moment hedonic responsivity in healthy volunteers. If these results can be confirmed in drug-naïve clinical samples, this would indicate that antipsychotic medication contributes to clinical anhedonia, probably via antagonistic effects at the dopamine D2 receptor.

Effect of Herbal Perfumes and Synthetic Perfumes on Attention and Cognitive Functions in Young Adults: A Sequential Cross-sectional Study

Introduction: Focused and sustained attention, executive function, working memory and task switching are important cognitive abilities. Efforts to enhance cognitive abilities, have engaged the scientific community since ages. Human beings are exposed to several fragrances and the perception of the sense of smell, plays an important role in the physiological effects of mood, stress, and working capacity. Perception of olfactory stimuli involves complex brain processing, which can be directly associated with cognition and emotion. Several Electroencephalogram (EEG) studies have revealed that, fragrances significantly modulate the activities of different brain waves and are responsible for various states of the brain. Aim: To objectively demonstrate the effect of olfactory stimulation with herbal (rose) perfume on attention and executive functions. Materials and Methods: This sequential cross-sectional study was conducted in the Department of Physiology at Osmania Medical College, Hyderabad, Telangana, India. The duration of the study was one month, from 16th August 2021 to 16th September 2021. Study included 40 healthy participants (15 males and 25 females), aged between 18-30 years to olfactory stimulation by herbal (rose) extract perfume and synthetic (rose) perfume, and the effects are assessed, using the psychophysiological tests viz., Rapid Serial Visual Presentation task (RSVP), Trail Making Tests (TMT) A&B, Ruff Figural Fluency Test (RFT), and compared with the baseline scores, which are then analysed using Paired t-test. The data was analysed by using Statistical Package for Social Sciences (SPSS) version 16.0. Results: Olfactory stimulation with herbal rose perfume enhances the attention and speed of processing, as shown by the nearly significant improvement in the performance of the TMT-A (p-value=0.05433), with decreased time taken to perform the test, whereas, the synthetic rose perfume enhanced the attention, speed, switching between tasks, cognitive fluency, and flexibility. This is evident by the significant improvement in the performance of the TMT-A (p-value=0.00326) and TMT-B (p-value=0.0001693), with decreased time taken to perform the tests. The derived index TMT (B-A), which removes the speed component and is a purer index of executive functions, also showed significant results (p-value=0.002092). Conclusion: The effects of herbal and synthetic rose olfactory stimulation have shown positive influence on the attention and cognitive functions and this finding can be applied to create student friendly learning environments, by providing pleasant stimuli through means of aromatic sprays delivering the odorant in a pulsatile manner at a frequency to overcome the ensuing olfactory adaptation.

The late positive potential during affective picture processing: Associations with daily life emotional functioning among adolescents with anxiety disorders

Pediatric anxiety disorders are characterized by potentiated threat responses and maladaptive emotion regulation (ER). The Late Positive Potential (LPP) is a neural index of heightened attention to emotional stimuli. Anxious individuals typically exhibit a larger LPP to unpleasant stimuli, but the LPP may also be blunted to unpleasant and pleasant stimuli for those with co-morbid depression. While a larger LPP is thought to reflect greater emotional reactivity, it is unknown to what extent variation in the LPP to laboratory stimuli corresponds to daily emotional functioning. We assessed the LPP in the laboratory in response to unpleasant, pleasant, and neutral images in combination with ecological momentary assessment of emotional reactivity and regulation in daily life among youth (9–14 years old; 55 % female) with anxiety disorders (ANX, N = 130) and no psychiatric diagnoses (ND, N = 47). We tested whether LPP amplitudes to unpleasant and pleasant stimuli (vs. neutral) are greater in ANX (vs. ND) youth and whether LPP amplitudes inversely correlate with co-morbid depression symptoms. We also examined associations between the LPP and daily life emotional functioning among ANX and ND youth. We found no group-by-valence effects on LPP amplitudes. Within ANX youth, higher depression symptoms were associated with smaller LPP amplitudes to unpleasant, but not pleasant, stimuli relative to neutral stimuli. Larger LPP amplitudes to emotional (relative to neutral) stimuli were correlated with use of specific ER strategies among ANX and ND youth but not emotional reactivity. While the LPP may reflect initial emotional reactivity to laboratory stimuli, it is associated with ER behaviors, and not emotional reactivity, in daily life.

Could Alcohol Abuse and Dependence on Junk Foods Inducing Obesity and/or Illicit Drug Use Represent Danger to Liver in Young People with Altered Psychological/Relational Spheres or Emotional Problems?

Recent data show that young people, mainly due to the pressure of some risk factors or due to disrupted interpersonal relationships, utilise greater reward value and display greater sensitivity to the reinforcing properties of “pleasurable stimuli”, specifically in those situations in which an enhanced dopamine release is present. Alcoholic beverages, foods rich in sugar and fat, and illicit drug use are pleasurable feelings associated with rewards. Research shows that there is a link between substance abuse and obesity in brain functioning. Still, alcohol excess is central in leading to obesity and obesity-related morbidities, such as hepatic steatosis, mainly when associated with illicit drug dependence and negative eating behaviours in young people. It is ascertained that long-term drinking causes mental damage, similarly to drug abuse, but also affects liver function. Indeed, beyond the pharmacokinetic interactions of alcohol with drugs, occurring in the liver due to the same metabolic enzymes, there are also pharmacodynamic interactions of both substances in the CNS. To complicate matters, an important noxious effect of junk foods consists of inducing obesity and obesity-related NAFLD. In this review, we focus on some key mechanisms underlying the impact of these addictions on the liver, as well as those on the CNS.

Anhedonia in endometriosis: An unexplored symptom.

Anhedonia is the diminished motivation and sensitivity to pleasurable stimuli. It has been reported to be more prevalent in patients with chronic pain as compared to healthy controls. Endometriosis is a chronic inflammatory systemic disease with a significant psychosocial impact that compromises wellbeing and the day-to-day life of patients. Women with endometriosis show significant psychological distress, even more pervasive when chronic pelvic pain is present. In the current review we will discuss the role of anhedonia in endometriotic chronic pelvic pain. We will also present new lines of research that could lead to more fully clarifying the psychological impact of endometriosis and its detrimental repercussions to quality of life and mental health.

Intolerance of uncertainty affects electrodermal responses during fear acquisition: Evidence from electrodermal responses to unconditional stimulus omission

Past research has shown that Intolerance of Uncertainty (IU) affects Pavlovian fear conditioning processes. In particular, extinction of learned fear is delayed in those reporting high IU. Reports of differences during acquisition are less consistent with most of the studies reporting no evidence for effects of IU. This may be due to past studies' focus on first interval electrodermal responses or fear potentiated startle, rather than on indices that may better capture uncertainty – like the response to the absence of a probabilistic unconditional stimulus. The current analysis combined data across three experiments that employed a 50 % reinforcement schedule and assessed electrodermal responses and (in two experiments) ratings of conditional stimulus pleasantness. Participants scoring high on IU showed overall larger electrodermal first interval responses during habituation and acquisition but did not differ from those scoring low on IU in differential conditioning (the difference between CS+ and CS-), as indicated by electrodermal first or second interval responses or ratings of CS pleasantness. However, participants high in IU showed larger differential third interval electrodermal responses to the omission of the electro-tactile unconditional stimulus during acquisition. Some evidence for this difference emerged in each experiment, supporting the reliability of the result. The current results suggest that effects of IU emerge in conditions of high uncertainty in Pavlovian fear learning tasks, such as during the omission of probabilistic unconditional stimuli.

The effect of the distraction of thought by music on pain relief in patients undergoing extracorporeal shock wave lithotripsy: A randomized controlled trial

Background and aims: The distraction of thought is a technique in which a pleasant stimulus is presented to the patient. This study aimed to investigate the effect of the distraction of thought by music on pain relief in patients undergoing extracorporeal shock wave lithotripsy (ESWL). Methods: This clinical trial was performed on 120 patients referring to Ayatollah Kashani Hospital in Shahrekord for ESWL in 2019. Patients were randomly divided into two experimental and control groups. In addition to routine care, the experimental group received the natural sound of the event, along with its beautiful scenery, while the control group only received routine care. The pain score was measured by the McGill Pain Questionnaire. The data obtained were analyzed by SPSS (version 18) using paired and independent t-tests and Tukey’s test. Results: The two groups were significantly different in terms of pain changes (P=0.007). The mean difference in addictive drug consumption between the control and experimental groups was significant (P=0 004). Conclusion: Thought distraction by music reduces pain and narcotic use of analgesics by the patients under ESWL.

Anhedonia. Depressive versus negative symptom

IntroductionAnhedonia is a symptom usually, and probably simplistically, defined as the inability to experience pleasure. It is considered one of the core symptoms of depression and a negative symptom of schizophrenia.ObjectivesWe intend to explore whether previous studies found common or dissimilar experiences of anhedonia in depression and schizophrenia.MethodsWe performed a review of the published literature on the subject using PubMed. We conducted a search using ‘anhedonia’, ‘schizophrenia’, and ‘depression’ as keywords.ResultsThere is different and diverging evidence on the matter. Historical reports associated schizophrenia with trait anhedonia, and depression with state anhedonia. More recently, some authors correlated appetitive anhedonia (lack of interest/desire) with schizophrenia, and consummatory anhedonia (lack of pleasure/enjoyment) with depression, but this was not corroborated by other studies. However, in line with it, there are findings of a normal physiological response to pleasurable stimuli among schizophrenics. Some authors propose that, in schizophrenia, this symptom might not represent an inability to feel pleasure but rather a deficient expression of its experience, as a part of blunted affect. Reward models highlight a deficit in reward learning in depression, but disorganization of reward processing and a focus on irrelevant clues in schizophrenia, which prevent patients from pursuing a pleasurable experience.ConclusionsThere are still limited studies comparing the experience of anhedonia in depression and schizophrenia. There seem to be significant differences between the two, but further studies are needed. In particular, this could be important in screening schizophrenic patients for depression.DisclosureNo significant relationships.

Modafinil acquires reinforcing effects when combined with citalopram

Modafinil (MOD) is a wakefulness promoter used to treat sleep disorders such as narcolepsy and obstructive sleep apnea. Its action mechanism consists in inhibiting dopamine (DAT) and norepinephrine (NET) transporters, but it has no affinity for the serotonin transporter (SERT). Modafinil's addictive potential is not yet clear, but one feature that differentiates it from potentially addictive drugs like cocaine revolves around affinity for SERT. The aims of the present study were to determine whether co-administration of MOD with the selective serotonin reuptake inhibitor citalopram (CIT) can increase MOD's psychostimulant effects on motor activity (MA), verify the effects of subsequent self-administration of MOD mixed with CIT, and document the presence of any symptoms of withdrawal. At 60 postnatal days (PD), male Wistar rats were treated chronically (16 days) with MOD at 30 or 60 mg/kg, with MOD+CIT at four dosage combinations administered to four groups (30MOD + CIT3, 30MOD + CIT5, 60MOD + CIT3, 60MOD + CIT5 mg/kg), or with a vehicle. After 40 min of daily drug administration, MA was measured on the open field test. MA increased only in the 60MOD group. The rats co-administered with 30MOD + 3CIT and 60MOD + 3CIT showed a decrease in the motivation to seek a pleasurable stimulus (lower consumption of sweet solution) after treatment concluded. The 60MOD and 60MOD + 3CIT groups showed MA sensitization after MOD intake. Additionally, higher self-administration of the mixture was observed in the groups pre-treated with 30MOD + 3CIT and 60MOD + 3CIT. Results suggest that serotonergic activity enhances modafinil's psychostimulant effects.