A distinct inferential mechanism for delusions in schizophrenia

Delusions, a core symptom of psychosis, are false beliefs that are rigidly held with strong conviction despite contradictory evidence. Alterations in inferential processes have long been proposed to underlie delusional pathology, but previous attempts to show this have failed to yield compelling evidence for a specific relationship between inferential abnormalities and delusional severity in schizophrenia. Using a novel, incentivized information-sampling task (a modified version of the beads task), alongside well-characterized decision-making tasks, we sought a mechanistic understanding of delusions in a sample of medicated and unmedicated patients with schizophrenia who exhibited a wide range of delusion severity. In this novel task, participants chose whether to draw beads from one of two hidden jars or to guess the identity of the hidden jar, in order to minimize financial loss from a monetary endowment, and concurrently reported their probability estimates for the hidden jar. We found that patients with higher delusion severity exhibited increased information seeking (i.e. increased draws-to-decision behaviour). This increase was highly specific to delusion severity as compared to the severity of other psychotic symptoms, working-memory capacity, and other clinical and socio-demographic characteristics. Delusion-related increases in information seeking were present in unmedicated patients, indicating that they were unlikely due to antipsychotic medication. In addition, after adjusting for delusion severity, patients as a whole exhibited decreased information seeking relative to healthy individuals, a decrease that correlated with lower socioeconomic status. Computational analyses of reported probability estimates further showed that more delusional patients exhibited abnormal belief updating characterized by stronger reliance on prior beliefs formed early in the inferential process, a feature that correlated with increased information seeking in patients. Other decision-making parameters that could have theoretically explained the delusion effects, such as those related to subjective valuation, were uncorrelated with both delusional severity and information seeking among the patients. In turn, we found some preliminary evidence that subjective valuation (rather than belief updating) may explain group differences in information seeking unrelated to delusions. Together, these results suggest that abnormalities in belief updating, characterized by stronger reliance on prior beliefs formed by incorporating information presented earlier in the inferential process, may be a core computational mechanism of delusional ideation in psychosis. Our results thus provide direct empirical support for an inferential mechanism that naturally captures the characteristic rigidity associated with delusional beliefs.

Sub-acute and long-term effects of ayahuasca on affect and cognitive thinking style and their association with ego dissolution

RATIONALE

Ayahuasca is a psychotropic plant tea from South America used for religious purposes by indigenous people of the Amazon. Increasing evidence indicates that ayahuasca may have therapeutic potential in the treatment of mental health disorders and can enhance mindfulness-related capacities. Most research so far has focused on acute and sub-acute effects of ayahuasca on mental health-related parameters and less on long-term effects.

OBJECTIVES

The present study aimed to assess sub-acute and long-term effects of ayahuasca on well-being and cognitive thinking style. The second objective was to assess whether sub-acute and long-term effects of ayahuasca depend on the degree of ego dissolution that was experienced after consumption of ayahuasca.

RESULTS

Ayahuasca ceremony attendants (N = 57) in the Netherlands and Colombia were assessed before, the day after, and 4 weeks following the ritual. Relative to baseline, ratings of depression and stress significantly decreased after the ayahuasca ceremony and these changes persisted for 4 weeks. Likewise, convergent thinking improved post-ayahuasca ceremony up until the 4 weeks follow-up. Satisfaction with life and several aspects of mindfulness increased the day after the ceremony, but these changes failed to reach significance 4 weeks after. Changes in affect, satisfaction with life, and mindfulness were significantly correlated to the level of ego dissolution experienced during the ayahuasca ceremony and were unrelated to previous experience with ayahuasca.

CONCLUSION

It is concluded that ayahuasca produces sub-acute and long-term improvements in affect and cognitive thinking style in non-pathological users. These data highlight the therapeutic potential of ayahuasca in the treatment of mental health disorders, such as depression.

S-Ketamine-Induced NMDA Receptor Blockade during Natural Speech Production and Its Implications for Formal Thought Disorder in Schizophrenia: A Pharmaco-fMRI Study

Structural and functional changes in the lateral temporal language areas have been related to formal thought disorder (FTD) in schizophrenia. Continuous, natural speech production activates the right lateral temporal lobe in schizophrenia, as opposed to the left in healthy subjects. Positive and negative FTD can be elicited in healthy subjects by glutamatergic NMDA blockade with ketamine. It is unclear whether the glutamate system is related to the reversed hemispheric lateralization during speaking in patients. In a double-blind, crossover, placebo-controlled study, 15 healthy, male, right-handed volunteers overtly described 7 pictures for 3 min each while BOLD signal changes were acquired with fMRI. As a measure of linguistic demand, the number of words within 20 s epochs was correlated with BOLD responses. Participants developed S-ketamine-induced psychotic symptoms, particularly positive FTD. Ketamine vs placebo was associated with enhanced neural responses in the right middle and inferior temporal gyri. Similar to a previous fMRI study in schizophrenia patients vs healthy controls applying the same design, S-ketamine reversed functional lateralization during speech production in healthy subjects. Results demonstrate an association between glutamatergic imbalance, dysactivations in lateral temporal brain areas, and FTD symptom formation.

The effect of oxytocin on group formation and strategic thinking in men

Decision-making in groups is a remarkable and decisive element of human societies. Humans are able to organize themselves in groups, engage in collaborative decision-making processes and arrive at a binding agreement, even in the absence of unanimous consent. However, the transfer of decision-making autonomy requires a willingness to deliberately expose oneself to the decisions of others. A lack of trust in the abilities of others or of the underlying decision-making process, i.e. public trust, can lead to a breakdown of organizations in political or economic domains. Recent studies indicate that the biological basis of trust on an individual level is related to Oxytocin, an endogenous neuropeptide and hormone, which is also associated with pro-social behavior and positive conflict resolution. However, little is known about the effects of Oxytocin on the inclination of individuals to form or join groups and to deliberately engage in collaborative decision-making processes. Here, we show that intranasal administration of Oxytocin (n = 60) compared to placebo (n = 60) in males causes an adverse effect on the choice for forming groups in the presence of a competitive environment. In particular, Oxytocin negatively affects the willingness to work collaboratively in a p-Beauty contest game, whereas the effect is most pronounced for participants with relatively high strategic sophistication. Since our data provide initial evidence that Oxytocin has a positive effect on strategic thinking and performance in the p-Beauty contest game, we argue that the adverse effect on group formation might be rooted in an enhanced strategic sophistication of participants treated with Oxytocin.

The effect of the muscarinic M1 receptor antagonist biperiden on cognition in medication free subjects with psychosis

The acetylcholine muscarinic M₁ receptor has been implicated in both psychosis and cognition. Post-mortem research has shown reduced muscarinic M₁ receptor density in 25% of chronic patients with schizophrenia. It is unknown whether reduced M₁ receptor density is related to cognitive symptoms of psychosis. We investigated the role of the M₁ receptor in separate cognitive domains in subjects with a psychotic disorder using a muscarinic M₁ antagonist as an acute pharmacological challenge. 33 young subjects with a psychotic disorder and 30 gender, age and IQ matched healthy controls were enrolled. All participants completed a comprehensive cognitive test battery twice: once after placebo and once after oral administration of 4mg. biperiden (M₁ antagonist). The order of drug administration was counterbalanced. Biperiden significantly negatively influenced both verbal (p< 0.001 and p=0.032) and visual learning and memory (p=0.028) in both groups. A medication x group interaction effect was found for reasoning and problem solving (p=0.005). No main or interaction effects were found for other cognitive domains. These results provide further in-vivo evidence that the M₁ receptor is involved in cognitive functioning, particularly verbal and visual memory processes. Lack of differential effects of biperiden between psychotic subjects and healthy controls may suggest that decreased M₁ receptor density is only present in chronic, older schizophrenia patients. However, it remains possible that differential effects of biperiden would be present in more severe cognitive impaired subjects with psychosis after several doses of biperiden instead of a single administration.

Antipsychotic treatment and the Rorschach Perceptual Thinking Index (PTI) in psychotic disorder patients: Effects of treatment

The Rorschach-based Perceptual Thinking Index (PTI) is used to identify and rate features of psychotic disorders, but effects of antipsychotic treatment on such ratings is not clear. Accordingly, we examined potential effects of antipsychotic drugs on PTI measures in 114 patients with a psychotic or bipolar-I disorder. Use and doses of antipsychotic drugs (as chlorpromazine-equivalent [CPZ-eq] mg/day) were unrelated to PTI total or subscale scores in any diagnostic group. PTI scores were independently and significantly associated with psychotic symptomatic severity (PANSS score) and less with female sex. These findings support the validity and value of the PTI in identifying features of psychosis even in the presence of antipsychotic treatment.

Ayahuasca enhances creative divergent thinking while decreasing conventional convergent thinking

INTRODUCTION

Ayahuasca is a South American psychotropic plant tea traditionally used in Amazonian shamanism. The tea contains the psychedelic 5-HT2A receptor agonist N,N-dimethyltryptamine (DMT), plus β-carboline alkaloids with monoamine oxidase-inhibiting properties. Increasing evidence from anecdotal reports and open-label studies indicates that ayahuasca may have therapeutic effects in treatment of substance use disorders and depression. A recent study on the psychological effects of ayahuasca found that the tea reduces judgmental processing and inner reactivity, classic goals of mindfulness psychotherapy. Another psychological facet that could potentially be targeted by ayahuasca is creative divergent thinking. This mode of thinking can enhance and strengthen psychological flexibility by allowing individuals to generate new and effective cognitive, emotional, and behavioral strategies. The present study aimed to assess the potential effects of ayahuasca on creative thinking.

METHODS

We visited two spiritual ayahuasca workshops and invited participants to conduct creativity tests before and during the acute effects of ayahuasca. In total, 26 participants consented. Creativity tests included the "pattern/line meanings test" (PLMT) and the "picture concept test" (PCT), both assessing divergent thinking and the latter also assessing convergent thinking.

RESULTS

While no significant effects were found for the PLMT, ayahuasca intake significantly modified divergent and convergent thinking as measured by the PCT. While convergent thinking decreased after intake, divergent thinking increased.

CONCLUSIONS

The present data indicate that ayahuasca enhances creative divergent thinking. They suggest that ayahuasca increases psychological flexibility, which may facilitate psychotherapeutic interventions and support clinical trial initiatives.

Improved cognitive content endures for 2 years among unstable responders to acute-phase cognitive therapy for recurrent major depressive disorder

BACKGROUND

The cognitive model of depression suggests that cognitive therapy (CT) improves major depressive disorder (MDD) in part by changing depressive cognitive content (e.g. dysfunctional attitudes, hopelessness). The current analyses clarified: (1) the durability of improvements in cognitive content made by acute-phase CT responders; (2) whether continuation-phase CT (C-CT) or fluoxetine (FLX) further improves cognitive content; and (3) the extent to which cognitive content mediates continuation treatments' effects on depressive symptoms and major depressive relapse/recurrence.

METHOD

Out-patients with recurrent MDD who responded to acute-phase CT (n = 241) were randomized to 8 months of C-CT, FLX or pill placebo (PBO) and followed for an 24 additional months. Cognitive content was assessed approximately every 4 months using five standard patient-report measures.

RESULTS

Large improvements in cognitive content made during acute-phase CT were maintained for 32 months, with 78-90% of patients scoring in normal ranges, on average. Cognitive content varied little between C-CT, FLX and PBO arms, overall. Small, transient improvements in cognitive content in C-CT or FLX compared with PBO patients did not clearly mediate the treatments' effects on depressive symptoms or on major depressive relapse/recurrence.

CONCLUSIONS

Outpatients with recurrent MDD who respond to acute-phase CT show durable improvements in cognitive content. C-CT or FLX may not continue to improve patient-reported cognitive content substantively, and thus may treat recurrent MDD by other paths.

Effects of methamphetamine administration on information gathering during probabilistic reasoning in healthy humans

Jumping to conclusions (JTC) during probabilistic reasoning is a cognitive bias repeatedly demonstrated in people with schizophrenia and shown to be associated with delusions. Little is known about the neurochemical basis of probabilistic reasoning. We tested the hypothesis that catecholamines influence data gathering and probabilistic reasoning by administering intravenous methamphetamine, which is known to cause synaptic release of the catecholamines noradrenaline and dopamine, to healthy humans whilst they undertook a probabilistic inference task. Our study used a randomised, double-blind, cross-over design. Seventeen healthy volunteers on three visits were administered either placebo or methamphetamine or methamphetamine preceded by amisulpride. In all three conditions participants performed the "beads" task in which participants decide how much information to gather before making a probabilistic inference, and which measures the cognitive bias towards jumping to conclusions. Psychotic symptoms triggered by methamphetamine were assessed using Comprehensive Assessment of At-Risk Mental States (CAARMS). Methamphetamine induced mild psychotic symptoms, but there was no effect of drug administration on the number of draws to decision (DTD) on the beads task. DTD was a stable trait that was highly correlated within subjects across visits (intra-class correlation coefficients of 0.86 and 0.91 on two versions of the task). The less information was sampled in the placebo condition, the more psychotic-like symptoms the person had after the methamphetamine plus amisulpride condition (p = 0.028). Our results suggest that information gathering during probabilistic reasoning is a stable trait, not easily modified by dopaminergic or noradrenergic modulation.

"Drinking won't get you thinking": a content analysis of adolescent-created print alcohol counter-advertisements

Involvement in creating antialcohol advertisements generates enthusiasm among adolescents; however, little is known about the messages adolescents develop for these activities. In this article, we present a content analysis of 72 print alcohol counteradvertisements created by high school (age 14-17 years old) and college (18-25 years old) students. The posters were content analyzed for poster message content, persuasion strategies, and production components, and we compared high school and college student posters. All of the posters used a slogan to highlight the main point/message of the ad and counterarguments/consequences to support the slogans. The most frequently depicted consequences were negative consequences of alcohol use, followed by negative-positive consequence comparison. Persuasion strategies were sparingly used in advertisements and included having fun/one of the gang, humor/unexpected, glamour/sex appeal, and endorsement. Finally, posters displayed a number of production techniques including depicting people, clear setting, multiple colors, different font sizes, and object placement. College and high school student-constructed posters were similar on many features (e.g., posters displayed similar frequency of utilization of slogans, negative consequences, and positive-negative consequence comparisons), but were different on the use of positive consequences of not using alcohol and before-after comparisons. Implications for teaching media literacy and involving adolescents and youth in developing alcohol prevention messages are discussed.

Effects of modafinil on non-verbal cognition, task enjoyment and creative thinking in healthy volunteers

Background

Modafinil, a putative cognitive enhancing drug, has previously been shown to improve performance of healthy volunteers as well as patients with attention deficit disorder and schizophrenia, mainly in tests of executive functions. The aim of this study was to investigate the effects of modafinil on non-verbal cognitive functions in healthy volunteers, with a particular focus on variations of cognitive load, measures of motivational factors and the effects on creative problem-solving.

Methods

A double-blind placebo-controlled parallel design study evaluated the effect of 200 mg of modafinil (N = 32) or placebo (N = 32) in non-sleep deprived healthy volunteers. Non-verbal tests of divergent and convergent thinking were used to measure creativity. A new measure of task motivation was used, together with more levels of difficulty on neuropsychological tests from the CANTAB battery.

Results

Improvements under modafinil were seen on spatial working memory, planning and decision making at the most difficult levels, as well as visual pattern recognition memory following delay. Subjective ratings of enjoyment of task performance were significantly greater under modafinil compared with placebo, but mood ratings overall were not affected. The effects of modafinil on creativity were inconsistent and did not reach statistical significance.

Conclusions

Modafinil reliably enhanced task enjoyment and performance on several cognitive tests of planning and working memory, but did not improve paired associates learning. The findings confirm that modafinil can enhance aspects of highly demanding cognitive performance in non-sleep deprived individuals.

This article is part of a Special Issue entitled ‘Cognitive Enhancers’.

Expecting innovation: psychoactive drug primes and the generation of creative solutions

Many individuals expect that alcohol and drug consumption will enhance creativity. The present studies tested whether substance related primes would influence creative performance for individuals who possessed creativity-related substance expectancies. Participants (n = 566) were briefly exposed to stimuli related to psychoactive substances (alcohol, for Study 1, Sample 1, and Study 2; and marijuana, for Study 1, Sample 2) or neutral stimuli. Participants in Study 1 then completed a creative problem-solving task, while participants in Study 2 completed a divergent thinking task or a task unrelated to creative problem solving. The results of Study 1 revealed that exposure to the experimental stimuli enhanced performance on the creative problem-solving task for those who expected the corresponding substance would trigger creative functioning. In a conceptual replication, Study 2 showed that participants exposed to alcohol cues performed better on a divergent thinking task if they expected alcohol to enhance creativity. It is important to note that this same interaction did not influence performance on measures unrelated to creative problem solving, suggesting that the activation of creativity-related expectancies influenced creative performance, specifically. These findings highlight the importance of assessing expectancies when examining pharmacological effects of alcohol and marijuana. Future directions and implications for substance-related interventions are discussed.

[Comparative analysis of ethanol effects on the spatial organization of biopotentials under conditions of open and closed eyes during different types of thinking]

Effects of low doses of ethanol on indices of spatial organization of cortical potentials (spatial synchronization, coherence, spectral power and information-power index) under the closed- and open-eyes conditions and during performance of divergent and convergent non-verbal and verbal tasks. Ethanol effect was shown to be more expressed under the open eyes-conditions as compared to that with the closed eyes. This finding may be associated with the greater effect of the stream of afferent information in the former case. Changes in topographical characteristics of the spatial synchronization of cortical potentials were more clearly localized and "specific" during divergent thinking as compared to the convergent type. Changes in the spectral power and information-power index testify to greater sensitivity to ethanol of divergent type of thinking as compared to convergent type. Psychological testing of stress resistance and impulsivity also showed a greater effect of ethanol on divergent thinking.

Disability associated with alcohol abuse and dependence

BACKGROUND

 Alcohol use disorders (AUD), i.e., alcohol dependence and abuse, are major contributors to burden of disease. A large part of this burden is because of disability. However, there is still controversy about the best disability weighting for AUD. The objective of this study was to provide an overview of alcohol-related disabilities.

METHODS

Systematic literature review and expert interviews.

RESULTS

There is heterogeneity in experts' descriptions of disabilities related to AUD. The major core attributes of disability related to AUD are changes of emotional state, social relationships, memory and thinking. The most important supplementary attributes are anxiety, impairments of speech and hearing.

CONCLUSIONS

This review identified the main patterns of disability associated with AUD. However, there was considerable variability, and data on less prominent patterns were fragmented. Further and systematic research is required for increasing the knowledge on disability related to AUD and for application of interventions for reducing the associated burden.

Gender, psychosis and psychotropic drugs: differences and similarities

Acute psychosis is diagnosed by clearly defined operational criteria embedded into international classification systems. Many studies have tried to determine the role of gender in psychosis but mainly in terms of epidemiology and course of illness, most often schizophrenia. There are however also important gender-specific differences in clinical symptoms of acute psychosis. No guidelines or treatment recommendations suggest gender as an important factor in the choice of antipsychotic treatment, which is true for all treatment modalities (antipsychotic, dose, duration). We will review shortly available literature and present some of our own research data on gender differences in clinical presentations of acute psychosis. When the diagnosis of an illness depends almost entirely on symptoms and their presentations as in the case of acute psychosis, important gender specific differences might challenge the diagnostic process as well as treatment choice and course of psychosis. Our as well as other data confirm that acute psychosis manifest itself differently in males and females. To define further the impact of observed differences we need further research into gender specific clinical and not just epidemiological variables.

Systemic infection and delirium: when cytokines and acetylcholine collide

Systemic infection and drugs with anticholinergic effects are well-recognised and prevalent risk factors for delirium in elderly people. Experimental findings and neuropathological observations suggest that activation of microglia is pivotal for mediation of the behavioural effects of systemic infections. The microglial response is usually regulated tightly, but defensive features could turn neurotoxic once microglial cells escape from cholinergic inhibition. A self-propelling neuroinflammatory reaction might follow, and this cascade could account for the strong association between delirium and long-term cognitive impairment and even dementia. Here, we propose a hypothetical model, suggesting that poor outcome after delirium can be averted in vulnerable elderly people by use of readily available drugs. Agents that either restore cholinergic control of microglia or directly inhibit neuroinflammation warrant testing in clinical trials.

Marijuana coping motives interact with marijuana use frequency to predict anxious arousal, panic related catastrophic thinking, and worry among current marijuana users

The present investigation evaluated whether coping motives for marijuana use interacted with past 30-day frequency of marijuana use in relation to anxiety-relevant variables among community-recruited young adult marijuana users (n=149). As expected, after covarying cigarettes per day, alcohol use, and total years of marijuana use, the interaction between frequency of past 30-day marijuana use and coping motives predicted anxious arousal symptoms, agoraphobic cognitions, and worry. Marijuana users who demonstrated high use frequency and high coping motives demonstrated the highest levels of anxiety across these anxiety-relevant criterion variables. No such effects were evident, as expected, for depressive symptoms, offering explanatory specificity for anxiety relative to depressive factors. These results are discussed in relation to better understanding the role of marijuana use and coping motives in regard to anxiety vulnerability.

Differential effects of erythropoietin on neural and cognitive measures of executive function 3 and 7 days post-administration

Erythropoietin (Epo) has neuroprotective and neurotrophic effects and improves cognitive function in animal models of neurodegenerative and neuropsychiatric illness. In humans, weekly Epo administration over 3 months improves cognitive function in schizophrenia. The neural underpinnings and time-course of this effect of Epo are currently unknown. It is also unclear whether the cognitive improvement reflects direct neurobiological actions or is secondary to hematological effects. We therefore assessed the actions of single administration of Epo (40,000 IU) vs. saline to healthy volunteers on cognitive and neural measures of executive function using a verbal fluency task and N-back working memory (WM) paradigm during functional magnetic resonance imaging (fMRI) on day 3 and 7 after administration in two separate cohorts of subjects. Epo modulated neuronal response in a fronto-parietal network during WM performance at both time points; on day 3 after administration, activation was increased in left-hemisphere frontal and cingulate cortex and reduced in the right parietal cortex; in contrast, neural response was enhanced in a right-lateralized fronto-parietal network and reduced in left-side regions 1 week post-administration. In addition, Epo-treated volunteers displayed improved verbal fluency performance 1 week post-administration. These effects occurred in the absence of changes in hematological measures suggesting that they reflect direct neurobiological actions of Epo. The findings are consistent with enduring effects of Epo on neurotrophic signaling and induction of neurochemical changes over time in neural networks typically affected in neuropsychiatric illness. The present study supports the notion that Epo may have clinical applications in the treatment of psychiatric disorder characterized by cognitive dysfunction.

Quetiapine versus risperidone in elderly patients with behavioural and psychological symptoms of dementia: efficacy, safety and cognitive function

OBJECTIVE

In this study we directly compared the efficacy and tolerability of the atypical antipsychotics quetiapine and risperidone in elderly patients with dementia and symptoms of disturbed perception, thought content, mood or behaviour (behavioural and psychological symptoms of dementia-BPSD).

METHODS

We conducted an 8-week, rater-blinded, randomised study of 72 outpatients (55-85 years) with BPSD (assessed by NPI baseline score), who received flexibly-dosed quetiapine (50-400 mg/day) or risperidone (0.5-2 mg/day). Primary efficacy measure: Neuropsychiatric Inventory (NPI) Parts 1 and 2; secondary efficacy measures: Clinical Global Impression (CGI), Cohen-Mansfield Agitation Inventory (CMAI), Mini-Mental State Examination (MMSE), Age-adjusted concentration test (AKT). Safety evaluations included the incidence of extrapyramidal symptoms (EPS) and adverse events (AEs).

RESULTS

Sixty-nine of 72 patients were evaluable for efficacy (72 were evaluated for safety), 4 patients discontinued (3 due to AEs: quetiapine 2, risperidone 1; 1 lost to follow-up). Sixty-five patients received quetiapine (n=34; mean dose 77+/-40 mg/day) or risperidone (n=31; mean dose 0.9+/-0.3 mg/day). There was no significant difference between treatments on NPI scores; within treatment groups, NPI scores decreased significantly from baseline to Week 8 (P<or=0.05 vs. baseline). Most patients (quetiapine arm 67.6%, risperidone arm 71.0%) experienced clinical improvement (CGI-Improvement scores); both agents reduced agitation (CMAI scores); and there was no cognitive impairment (MMSE and AKT scores). There were no significant differences between treatments in any safety measures, including EPS. Four patients experienced serious AEs (quetiapine arm 3; risperidone arm 1); none were considered treatment-related by the study investigator. There were no cerebrovascular AEs or deaths.

CONCLUSIONS

Quetiapine or risperidone, at low doses, were equally effective and generally well tolerated (including no cognitive impairment) in the treatment of BPSD in elderly patients.

Brain activation in elderly people with and without dementia: Influences of gender and medication

Patients suffering from dementia show altered functional brain activation patterns especially in prefrontal brain regions, as research suggests. The present study follows three aims: to replicate these findings, to investigate treatment effects when administering galantamine, and to put gender differences in focus. We compared 12 patients with dementia to 12 age- and gender-matched healthy subjects regarding changes in haemoglobin concentration in brain tissue while performing a verbal fluency task (VFT). Concentration changes of oxygenated (O(2)Hb) and deoxygenated (HHb) haemoglobin were measured by multi-channel near-infrared spectroscopy (NIRS), an easily applicable and non-invasive method of optical topography. In the patient group, measurement was repeated 4 and 8 weeks after starting treatment with galantamine. The results showed a reduced increase in O(2)Hb during task performance for patients compared to healthy controls. Furthermore, female subjects showed more pronounced activation in O(2)Hb as well as HHb compared to male subjects. Regarding treatment effects, no clear results could be obtained. In HHb, evidence for an entrainment effect was found. In the light of existing literature, the present study suggests an interaction of gender and age regarding brain activation patterns which should be aimed at in future investigations.

An association of intrusive, repetitive phrases with lamotrigine treatment in bipolar II disorder

INTRODUCTION

Bipolar disorder is frequently associated with obsessional symptoms. However, no reports have identified a pattern of obsessionality that is associated with a specific mood stabilizer treatment.

METHODS

A chart review was conducted on five patients with bipolar II disorder who spontaneously reported a form of obsessionality characterized by intrusive, recurrent phrases after taking lamotrigine.

RESULTS

Development of the phrases occurred from 7-42 years after mood disorder onset and occurred only after initiation of lamotrigine treatment. The phrases improved with lamotrigine discontinuation or dose reduction and recurred with lamotrigine re-challenge or upon dose escalation.

CONCLUSION

A possible mechanism for the development of the intrusive phrases involves the influence of lamotrigine on glutamatergic regulation in a bipolar II disorder population vulnerable to the expression of obsessionality. Limitations of this report include its observational nature, small number of cases reported, and confound of concomitant medication use.

Differential roles of dopamine D1 and D2 receptors in the nucleus accumbens in attentional performance on the five-choice serial reaction time task

Nucleus accumbens (NAC) dopamine may play a role in attentional and executive processes, as it modulates cortico-limbic inputs, including afferents from the prefrontal cortex. The present study examined the role of NAC dopamine D1 and D2 receptors in visual attentional processes and response control in rats as assessed in the five-choice serial reaction time task (5CSRT). Rats were trained to detect the location of brief (0.5 s) visual targets presented randomly in an array of five apertures to receive food reward. They were tested after bilateral infusions of a D1 receptor antagonist (SCH 23390) and agonist (SKF 38393) and a D2 receptor antagonist (sulpiride) and agonist (quinpirole) into the NAC. While intra-NAC SCH 23390 decreased accurate responding and increased response omissions, SKF 38393 improved accuracy and decreased omissions at the lowest dose (0.1 microg/side). At higher doses, SKF 38393 increased premature 'impulsive' responding. Sulpiride impaired the attentional accuracy of responding and slowed the latency to collect the earned food reward. By contrast, intra-NAC infusions of quinpirole did not significantly affect attentional accuracy, but increased perseverative responding. Optimal performance on the 5CSRT depends on both D1 and D2 receptors in the NAC, but they modulate different aspects of performance. D1 receptor agents had more selective effects on attentional accuracy while D2 receptor stimulation did not affect accuracy or premature responses, but enhanced perseverative responding. The data are discussed in terms of the different functions of NAC dopamine receptors in the processing of information from its different cortico-limbic inputs.

Duloxetine: meta-analyses of suicidal behaviors and ideation in clinical trials for major depressive disorder

BACKGROUND

Uncertainty regarding relationships of antidepressant treatment and suicidality encouraged systematic review of data on suicidal behaviors and ideation from Phase II and III clinical trials of duloxetine for major depressive disorder (MDD).

METHODS

We evaluated all completed duloxetine trials in MDD with data lock by February 2, 2004. We compared incidence of suicide-related events with duloxetine versus placebo in controlled trials, using Mantel-Haenszel incidence difference (MHID) and exposure time-adjusted rate difference (MHRD) methods, and analyzed changes in Hamilton Depression Scale (HAMD) Item-3 (suicidality) scores.

RESULTS

There were no significant differences in the incidence of suicide-related events with duloxetine versus placebo in 12 placebo-controlled trials (duloxetine, 1812; placebo, 1184 [corrected] patients). The MHID for suicide-related behaviors was -0.03% (95% confidence interval [CI], -0.48 to 0.42) and MHRD -0.002 (95% CI, -0.02 to 0.02). Changes in HAMD Item-3 suicidality scores showed more improvement with duloxetine (MHID, 9.56%; 95% CI, 4.50 to 14.6; P < 0.001) and less worsening of suicidal ideation with duloxetine (MHID, -4.25%; 95% CI, -6.55 to -1.95; P < 0.001). Other Item-3 findings showed no consistent pattern; a slightly higher proportion of duloxetine-treated patients with a change from 0 (absent) to 3 was balanced against a higher proportion of placebo-treated patients changing from 0 to 2.

CONCLUSIONS

We found no evidence of an increased risk of suicidal behaviors or ideation during treatment with duloxetine compared with placebo in MDD patients. HAMD Item-3 suicidality scores had more improvement and less worsening of suicidal ideation with duloxetine than placebo.

Treatment resistance in unipolar depression: Is it an iatrogenic phenomenon caused by antidepressant treatment of patients with a bipolar diathesis?

Major depressive disorder is a common psychiatric illness that is considered generally treatable; however, there are some patients who fail to respond in spite of adequate trials of antidepressants. Clinical factors known to contribute to treatment resistance include psychiatric and physical comorbidity, undiagnosed bipolarity, and treatment non-adherence. There is also emerging evidence that the use of antidepressants in some 'unipolar' patients may lead to a pattern of progressive diminution of therapeutic response and ultimately treatment resistance. A large number of these patients may have a bipolar diathesis even though there are no symptoms of hypomanic, manic or mixed episodes. It is hypothesized that the widespread and injudicious use of antidepressants in patients with a bipolar diathesis might result in treatment-induced resistant depression. Furthermore, attempts to manage the antidepressant-led mood instability might cause increased utilisation of other psychotropic drugs including sedative/hypnotics, neuroleptics and mood stabilisers and contribute to polypharmacotherapy.

Non-degenerative mild cognitive impairment in elderly people and use of anticholinergic drugs: longitudinal cohort study

OBJECTIVE

To assess the potential of anticholinergic drugs as a cause of non-degenerative mild cognitive impairment in elderly people.

DESIGN

Longitudinal cohort study.

SETTING

63 randomly selected general practices in the Montpellier region of southern France.

PARTICIPANTS

372 people aged > 60 years without dementia at recruitment.

MAIN OUTCOME MEASURES

Anticholinergic burden from drug use, cognitive examination, and neurological assessment.

RESULTS

9.2% of subjects continuously used anticholinergic drugs during the year before cognitive assessment. Compared with non-users, they had poorer performance on reaction time, attention, delayed non-verbal memory, narrative recall, visuospatial construction, and language tasks but not on tasks of reasoning, immediate and delayed recall of wordlists, and implicit memory. Eighty per cent of the continuous users were classified as having mild cognitive impairment compared with 35% of non-users, and anticholinergic drug use was a strong predictor of mild cognitive impairment (odds ratio 5.12, P = 0.001). No difference was found between users and non-users in risk of developing dementia at follow-up after eight years.

CONCLUSIONS

Elderly people taking anticholinergic drugs had significant deficits in cognitive functioning and were highly likely to be classified as mildly cognitively impaired, although not at increased risk for dementia. Doctors should assess current use of anticholinergic drugs in elderly people with mild cognitive impairment before considering administration of acetylcholinesterase inhibitors.

Oral clonidine pretreatment prior to venous cannulation

Clonidine is a preferential alpha-2 agonist drug that has been used for over 35 years to treat hypertension. Recently, it has also been used as a preoperative medication and as a sedative/anxiolytic drug. This randomized, double-blind, placebo-controlled crossover clinical trial characterized the effects of oral clonidine pretreatment on intravenous catheter placement in 13 patients. Parameters measured included the bispectral index (BIS), Observer's Assessment of Alertness/Sedation Scale (OAA/S), frontal temporal electromyogram (EMG), 30-Second Blink Count (Blink), Digit Symbol Substitution Test (DSST), State Anxiety Inventory (SAI), fingertip versus forearm skin temperatures, and multiple questionnaires. Oral clonidine significantly decreased SAI scores, OAA/S, EMG, and Blink, but did not cause statistically significant BIS or DSST reductions. Subjects preferred oral clonidine pretreatment prior to venipuncture compared to placebo. Questionnaires also indicated that clonidine provided minimal sedation, considerable anxiolysis, and some analgesia. Fingertip versus forearm skin temperature differentials were decreased. Reduced fingertip versus forearm temperature differentials suggest increased peripheral cutaneous blood flow prior to venous cannulation. Oral clonidine pretreatment not only helped control patient anxiety and pain but also provided cardiovascular stability.

[Suicidal ideations and suicide attempts after starting on aripiprazole, a new antipsychotic drug]

In 5 patients, 3 women aged 30, 32 and 41 years and 2 men aged 36 and 56 years, serious side effects developed after starting aripiprazole, a new antipsychotic drug. 2 patients had not been treated with antipsychotic drugs before, while in 3 there was a switch in antipsychotic treatment. The side effects consisted primarily oftroubling feelings ofagitation, akathisia, insomnia and dysphoria. 3 of the patients made a suicide attempt and 2 developed suicidal thoughts. The patients had not previously attempted suicide and the suicidal thoughts disappeared after discontinuation ofaripiprazole. Suicidal tendencies have not been reported before as a side effect ofaripiprazole.

Cosmetic neurology

Advances in cognitive neuroscience and neuropharmacology are yielding exciting treatments for neurologic diseases. Many of these treatments are also likely to have uses for people without disease. Here, I review the ways in which medicine might make bodies and brains function better by modulating motor, cognitive, and affective systems. These potential "quality of life" interventions raise ethical concerns, some related to the individual and others related to society. Despite these concerns, I argue that major restraints on the development of cosmetic neurology are not likely. Neurologists and other clinicians are likely to encounter patient-consumers who view physicians as gatekeepers in their own pursuit of happiness.

Reduced heart rate variability in chronic alcohol abuse: relationship with negative mood, chronic thought suppression, and compulsive drinking

BACKGROUND

Previous research suggests that heart rate variability (HRV) may be an important factor in various maladaptive psychological conditions.

METHODS

This study was conducted to investigate vagal tone assessed as tonic vagally mediated heart rate variability in alcoholic (n = 49) and control subjects (n = 45).

RESULTS

Alcoholic subjects had faster heart rate and lower preimaginary exposure levels of HRV compared with the control group. An increase in HRV was observed in the alcoholic group when subjects were exposed to an imaginary alcohol script. Tonic HRV was found to be related inversely to negative mood and chronic thought suppression and positively to positive mood. Furthermore, the compulsive subscale of the Obsessive Compulsive Drinking Scale (OCDS) was inversely related to HRV during the imaginary alcohol exposure.

CONCLUSIONS

It is concluded that the findings are in agreement with the neurovisceral integration model of affective regulation, which claims that dysfunctional psychologic states are rooted in an impaired inhibitory mechanism that is associated with low HRV.

Can we help addicts become more autonomous? Inside the mind of an addict

I examine the impact of addiction on autonomy in terms of the standard literature on addiction--referred to also as 'substance dependence.' Then in terms of the criteria for substance dependence, by developing a set of practical strategies to help people with addictions think more clearly, I test the idea of whether addicts can be helped to become more autonomous. Given that unsuccessful attempts to quit constitute part of the criteria of substance dependence, I look at what goes wrong when people try to quit using a substance. The subjective experience of addiction is an important aid in understanding addiction and first person accounts and literary characterisations of addiction provide insight into the addict's mind and assist us in deciding whether addicts can be helped to become more autonomous.

Acute influences of estrogen and testosterone on divergent and convergent thinking in postmenopausal women

Previous studies indicated an enhanced capability of divergent creative thinking in young women during the ovulatory phase, which expressed itself also by an increased dimensional complexity of ongoing electroencephalographic (EEG) activity. Considering the enhanced plasma levels of estrogen and testosterone characterizing the ovulatory phase, we tested whether short-term administration of estrogen or testosterone in postmenopausal women with constantly low levels of gonadal steroids induces similar changes in divergent thinking. In two placebo-controlled cross-over studies, healthy postmenopausal women (n=12, in each study, mean age 58 years, range 47-65 years) were treated transdermally over 3 days with estrogen and testosterone, respectively, at doses inducing plasma hormone concentrations comparable with those observed in young women around ovulation. Capabilities of divergent thought and convergent analytical thought, performance on motor perseveration, and verbal memory were examined. EEG activity was recorded while subjects performed on tasks of thinking and during mental relaxation. Estrogen impaired divergent thinking (p <0.01) and enhanced convergent thinking, motor perseveration, and memory for the initial word list (p <0.05 for all tests). In parallel, EEG dimensional complexity was reduced (p <0.05). Overall, these changes indicate an estrogen-induced shift from a "divergent" towards a more "convergent" mode of processing. However, overall less consistent, effects of testosterone were opposite to those of estrogen. It increased performance on some of the divergent thinking tasks (p <0.05), and tended to increase EEG dimensional complexity during divergent thinking. Data indicate a differential sensitivity of modes of thinking to short-term treatment with estrogen and testosterone in postmenopausal women.

Time effects of food intake on the pharmacokinetics and pharmacodynamics of quazepam

AIMS

There is little information on interaction between food and the hypnotic agent quazepam. We therefore studied the effects of food and its time interval on the pharmacokinetics and pharmacodynamics of quazepam.

METHODS

A randomized three-phase crossover study with 2-week intervals was conducted. Nine healthy male volunteers took a single oral 20 mg dose of quazepam under the following conditions: 1) after fasting overnight; 2) 30 min after eating standard meal; or 3) 3 h after eating the same meal. Plasma concentrations of quazepam and its metabolite, 2-oxoquazepam and psychomotor function using the Digit Symbol Substitute Test (DSST), Stanford Sleepiness Scale (SSS) and Visual Analogue Scale were measured up to 48 h.

RESULTS

During the food treatments at 30 min and 3 h before dosing, the peak concentrations (Cmax) were 300% (95% CI 260, 340%; P < 0.001) and 250% (95% CI 210, 290%; P < 0.01) of the corresponding value during the fasting phase. For quazepam, the area under the plasma concentration-time curve from 0 to 8 h measured at 30 min and 3 h before dosing was significantly increased, with the food treatments by 2.4-fold (95% CI 2.0; 2.8-fold; P < 0.001) and 2.1-fold (95% CI 1.7; 2.4-fold; P < 0.01), respectively. In response to pharmacokinetic changes, some of the pharmacodynamics (DSST, P < 0.05; SSS, P < 0.05) differed significantly between fasted status and fed status. No difference was found in any pharmacokinetic or pharmacodynamic parameters between the two food treatment phases.

CONCLUSIONS

A food effect on quazepam absorption is evident and continues at least until 3 h after food intake. The dosing of quazepam after a long period of ordinary fasting might reduce its efficacy because a 3 h interval between the timing of the evening meal and bedtime administration of hypnotics is regarded as normal in daily life.

Intractable depression or psychosis

OBJECTIVE

Some patients with treatment resistant depression may have a difficult to recognize and therefore untreated thought disorder. Even a subtle disorder may significantly impact patients' lives. This case illustrates a mechanism for identifying and treating this subgroup of patients.

METHOD

The treatment of a 67-year-old female with intractable depression is described.

RESULTS

The Rorschach Exner Comprehensive System identified the presence of a thought disorder with four out of five conditions positive on the Schizophrenia Index and five out of seven conditions positive on the Depression Index. Low-dose risperidone was added to the patient's medications with excellent results. Post-testing indicated that the Schizophrenia and Depression Indices were no longer positive.

CONCLUSION

A subgroup of patients with intractable depression may have an underlying thought disorder that can be identified with the Rorschach and successfully treated with low-dose antipsychotic medication.

The effects of psychoactive drugs and neuroleptics on language in normal subjects and schizophrenic patients: a review

The aim of this survey is to present an overview of research into psychopharmacology as regards the effects of different psychoactive drugs and neuroleptics (NL) on language in normal subjects and schizophrenic patients. Eighteen studies that have investigated the effects of different drugs (alcohol, amphetamines, secobarbital, L-dopa, psilocybin, ketamine, fenfluramine) and neuroleptics (conventional and atypical) on language are reviewed. There are no studies concerning the effects of neuroleptics on language in healthy subjects. The results of the effects of other molecules indicate that language production can be increased (alcohol, amphetamine, secobarbital), rendered more complex (d-amphetamine), more focused (L-dopa) or more unfocused (psilocybin) and clearly impaired (ketamine). For schizophrenic patients, most studies show that conventional neuroleptic treatments, at a therapeutic dosage and in acute or chronic mode, reduce language disorders at all levels (clinic, linguistic, psycholinguistic). In conjunction with other molecules, the classical NL, when administered at a moderate dosage and in chronic mode, modify language in schizophrenia, either by improving the verbal flow and reducing pauses and positive thought disorder (NL + amphetamine) or by inducing an impairment in the language measurements (NL + fenfluramine). Clinical, methodological and theoretical considerations of results are debated in the framework of schizophrenic language disorders.

Midazolam attenuates ketamine-induced abnormal perception and thought process but not mood changes

PURPOSE

To determine the effects of midazolam, 30 ngxmL(-1), on altered perception, mood, and cognition induced by ketamine.

METHODS

After ketamine was administered to achieve target concentrations of 50, 100, or 150 ngxmL in 11 volunteers, perception, mood, and thought process were assessed by a visual analog scale. Mini-Mental State examination (MMSE) assessed cognition. Boluses of midazolam, 30, 14.5, and 12 microgxkg(-1), were injected every 30 min to maintain the plasma concentration at 30 ngxmL(-1), which was reached 30 min after each injection.

RESULTS

Ketamine produced changes in perception about the body (P < 0.01, 0.001, and 0.0001 at 30, 60, and 90 min), surroundings (P < 0.01 and 0.0001 at 60 and 90 min), time (P < 0.002 and 0.0001 at 60 and 90 min), reality (P < 0.001 and 0.0001 at 60 and 90 min), sounds (P < 0.002 at 90 min), and meaning (P < 0.05 at 90 min). Subjects felt less energetic and clearheaded (P < 0.02 and 0.05) during ketamine, midazolam, and their co-administration. Ketamine impaired thought process (P < 0.003 and 0.0001 at 60 and 90 min). Ketamine and midazolam decreased mean total MMSE and recall scores (P < 0.001 for both). Co-administration reduced the number of subjects with perceptual (body, P < 0.01 and 0.001 at 30 and 60 min) and thought process abnormalities. Within the range of observation, co-administration did not affect the changes in mood or recall.

CONCLUSION

Midazolam attenuates ketamine-induced changes in perception and thought process.

Effects of neuroleptic medications on speech disorganization in schizophrenia: biasing associative networks towards meaning

BACKGROUND

While some cognitive accounts of disorganized speech, or thought disorder, in schizophrenia have emphasized failures in working memory/discourse planning or selective attention, we have suggested that thought disorder resides in the semantic system. In this study we assessed the effect of neuroleptic medication on thought disorder and semantic processing.

METHODS

Seventeen patients with schizophrenia were assessed while receiving neuroleptic medications and in crossover fashion, placebo. A number of measures were obtained: clinically rated thought disorder (using the Thought, Language and Communication Scale); working memory letter number span); lexical integrity (naming and receptive vocabulary); and, semantic priming of intracategorical word pairs.

RESULTS

Semantic priming measures improved with neuroleptic medication, as did clinically rated thought disorder. No other measure changed significantly. Priming selectively covaried with changes in thought disorder.

CONCLUSION

Changes in spreading semantic activation, measured in a semantic priming paradigm and presumably brought about by neuroleptics' influence on dopaminergic neuromodulatory systems, might reflect changes in the biases of pre-existing associative networks that favour or increase the accessibility of representations related by shared features. This study also has implications for the architecture of normal language in that a dissociation between the lexical and semantic levels was observed, due to the selective compromise of tasks demanding semantic processing.

Abstinence effects and reactivity to nicotine during 11 days of smoking deprivation

The purpose of the present study was to investigate smoking abstinence effects and the dissipation of tolerance (reactivity to nicotine) under controlled laboratory conditions. Seventeen male and female regular smokers were tested first in a session following ad libitum smoking and then in an additional five sessions over the course of 11 days during which they abstained from smoking. A metered dose of nicotine was administered via intranasal spray to ensure standard exposure, and pre- and post-dosing measures of heart rate, blood pressure, cortisol, galvanic skin response (GSR), craving, and several DSM-IV withdrawal symptoms (anxiety, irritability, restlessness, difficulty concentrating, and appetite) were collected. Prior to the nicotine test dose during deprivation sessions, heart rate and systolic blood pressure evinced elements of both an 'offset abstinence pattern' (deflection in a direction opposite to that produced by smoking) and a 'transient abstinence pattern' (deflection followed by a subsequent return); for cortisol, an offset pattern was observed, whereas for GSR and craving, a transient pattern was found. With respect to loss of tolerance, heart rate reactivity was found to increase significantly after 2 days' abstinence from nicotine, and the increase was sustained in subsequent sessions. Cortisol reactivity revealed more gradual dissipation, with significant differences evident only after 9 days of abstinence. These findings extend research on nicotine abstinence effects and on the dissipation of tolerance to nicotine deprivation intervals of nearly 2 weeks and confirm prior observations of variability across different response systems.

Effects of lovastatin on cognitive function and psychological well-being

PURPOSE

Animal research and cross-sectional studies suggest that serum lipid concentrations may influence cognitive function, mood, and behavior, but few clinical trials have studied these effects.

SUBJECTS AND METHODS

In this double-blind investigation, 209 generally healthy adults with a serum low-density-lipoprotein (LDL) cholesterol level of 160 mg/dL or higher were randomly assigned to 6-month treatment with lovastatin (20 mg) or placebo. Assessments of neuropsychological performance, depression, hostility, and quality of life were conducted at baseline and at the end of the treatment period. Summary effect sizes were estimated as z scores on a standard deviation (SD) scale.

RESULTS

Placebo-treated subjects improved between baseline and posttreatment periods on neuropsychological tests in all five performance domains, consistent with the effects of practice on test performance (all P <0.04), whereas those treated with lovastatin improved only on tests of memory recall (P = 0.03). Comparisons of the changes in performance between placebo- and lovastatin-treated subjects revealed small, but statistically significant, differences for tests of attention (z score = 0.18; 95% confidence interval (CI), 0.06 to 0.31; P = 0.005) and psychomotor speed (z score = 0.17; 95% CI, 0.05 to 0.28; P = 0. 004) that were consistent with greater improvement in the placebo group. Psychological well-being, as measured several ways, was not affected by lovastatin.

CONCLUSION

Treatment of hypercholesterolemia with lovastatin did not cause psychological distress or substantially alter cognitive function. Treatment did result in small performance decrements on neuropsychological tests of attention and psychomotor speed, the clinical importance of which is uncertain.

The effects of 3-week estrogen hormone replacement on cognition in elderly healthy females

RATIONALE

Estrogen concentrations decline with age and menopause is often followed by an acceleration of the age effects on cognition. It is suggested that replacement of estrogen would reinstate, at least in part, cognitive abilities. Effects of estrogens on memory have been reported in studies with women in a clinical setting who either needed or wished to have the estrogen replacement and are mostly in the perimenopausal age-band.

OBJECTIVE

The present study investigated the effects of estradiol on memory and on frontal lobe function in elderly female subjects who did not suffer any of the postmenopausal symptoms and had never taken estrogen hormone replacement (EHR) previously.

METHODS

EHR (Progynova TS, transdermal estradiol; n=19) or placebo (n=18) was given for a period of 3 weeks to elderly healthy female subjects. Memory, frontal lobe functions (inhibition and planning) and visuospatial abilities (mental rotation) were tested before and after treatment. Estrogen plasma levels were measured to confirm the result of EHR. Cortisol plasma levels were also measured before and after cognitive performance in order to evaluate the effects of EHR on the sensitivity of the hypothalamo-pituitary-adrenal (HPA) axis to mild mental stress.

RESULTS

Plasma estradiol levels in the drug group increased to levels equivalent to that of a fertile woman (0.21+/-0.5 nmol/l). Memory function as well as visuospatial abilities as measured by a mental rotation task improved significantly with EHR. However, there was no effect of EHR on frontal lobe functions. The cognitive effects were not dependent on an improvement in mood or general well-being as may be the case with EHR in women at peri- or post-menopausal stage. EHR was found to increase the HPA response to task-induced stress, as indicated by an increase in cortisol plasma levels.

CONCLUSIONS

The present study has provided evidence of a beneficial effect of EHR on cognitive abilities given for first time to healthy elderly women. Furthermore, the present study has demonstrated a differential effect of EHR on memory, visuospatial abilities and frontal lobe function.

Influence of individual differences in craving and obsessive cocaine thoughts on attentional processes in cocaine abuse patients

In the present pilot-study, the relation between craving, obsessive thoughts about cocaine, experienced control, and attentional bias for cocaine related words is investigated. Sixteen cocaine abuse patients participated in a reaction time (RT) experiment which was employed to measure the ability of subjects to shift their attention away from cocaine related words. Postexperiment craving was found to be positively correlated with reaction times on drug related cues, in contrast to RT on neutral cues. Furthermore, obsessive thoughts about cocaine use and the experienced cocaine use control, in the week before the experiment, were correlated in a higher degree with RTs on drug cues than postexperiment craving. Attentional bias for drug cues was evidenced in patients with higher scores on obsessive cocaine thoughts and higher craving scores. This study shows that individual differences on information processing, within a cocaine abuse patient population, are present.

Triazolam-induced changes in alcoholic thought processes

This study was designed to examine and contrast cognitive effects (explicit memory and access to semantic knowledge) of the benzodiazepine Halcion (triazolam) in ten normal volunteers and ten cognitively un-impaired detoxified alcoholics. The two groups were indistinguishable from one another under placebo conditions on all measures of cognitive functioning. Under Halcion test conditions (0.375 mg p.o.), both groups were about equally impaired in their recall of to-be-remembered information. However, alcoholics, were more likely to recall information that they were not asked to remember (intrusion errors) on all measures of explicit remembering. Alcoholics also generated relatively uncommon (low frequency) responses from semantic memory, rather than common, categorically related associations in response to stimuli such as types of vegetables, flowers, and fruit following the administration of Halcion, but were not different from normal volunteers in the types of responses generated under placebo conditions. These findings suggest that a drug challenge that simulates many of the effects of acute alcohol administration induces alcoholics to think and remember differently (qualitatively) from normal volunteers.

Drug-induced akathisia and suicidal tendencies in psychotic patients

Five patients, while being treated with high potency antipsychotic drugs developed akathisia and tended towards committing suicide as a consequence of the inner agitation and restlessness they were suffering. Upon discontinuation of the respective medication or switching to low potency drugs, as well as addition of anti-parkinson drugs or benzodiazepines, the akathisia and suicidal tendencies abated. Clinicians ought to be aware of suicidal impulses emerging in patients suffering from akathisia. By prompt recognition and treatment of akathisia such suicidal tendencies and attempts can be prevented.

Effects of ketamine on thought disorder, working memory, and semantic memory in healthy volunteers

BACKGROUND

The N-methyl-D-aspartate receptor antagonist, ketamine, produces a clinical syndrome of thought disorder, perceptual distortion, and cognitive impairment.

METHODS

We have administered ketamine to healthy volunteers to characterize the formal thought disorder and specific memory dysfunction associated with ketamine. Ten healthy volunteers underwent a double-blind, placebo-controlled, ketamine infusion (0.12 mg/kg bolus and 0.65 mg/kg/hour). Thought disorder was evaluated with the Scale for the Assessment of Thought, Language and Communication. Cognitive testing involved working and semantic memory tasks.

RESULTS

Ketamine produced a formal thought disorder, as well as impairments in working and semantic memory. The degree of ketamine-induced thought disorder significantly correlated with ketamine-induced decreases in working memory and did not correlate with ketamine-induced impairments in semantic memory.

CONCLUSIONS

This study characterizes the formal thought disorder associated with ketamine and may suggest that ketamine-induced deficits in working memory are associated with ketamine-induced thought disorder.