[Anti-impulsivity drugs and their mechanisms of action]

Higher impulsivity could be a risk factor for drug addiction, criminal involvement, and suicide. Moreover, poor inhibitory control is observed in several psychiatric disorders such as attention-deficit/hyperactivity disorder, schizophrenia, and bipolar disorder. Thus it is preferred that clinical drugs have anti-impulsive effects in addition to the therapeutic effects on the primary disease. At least it is better to use clinical drugs that do not increase impulsivity. We have developed a 3-choice serial reaction time task and examined the effects of clinical drugs on impulsivity in rats using the task. We have found several anti-impulsive drugs (lithium, tandospirone, and milnacipran) and elucidated the mechanism of action in some of these drugs. For example, we demonstrated that milnacipran enhanced the control of impulsive action by activating D1-like receptors in the infralimbic cortex. In this review, we introduce recent advances in this field and suggest future directions to develop anti-impulsive drugs.

Prosocial effects of oxytocin in two mouse models of autism spectrum disorders

Clinical evidence suggests that oxytocin treatment improves social deficits and repetitive behavior in autism spectrum disorders (ASDs). However, the neuropeptide has a short plasma half-life and poor ability to penetrate the blood-brain barrier. In order to facilitate the development of more bioavailable oxytocinergic compounds as therapeutics to treat core ASD symptoms, small animal models must be validated for preclinical screens. This study examined the preclinical utility of two inbred mouse strains, BALB/cByJ and C58/J, that exhibit phenotypes relevant to core ASD symptoms. Mice from both strains were intraperitoneally administered oxytocin, using either acute or sub-chronic regimens. Acute oxytocin did not increase sociability in BALB/cByJ; however, sub-chronic oxytocin had significant prosocial effects in both BALB/cByJ and C58/J. Increased sociability was observed 24 h following the final oxytocin dose in BALB/cByJ, while prosocial effects of oxytocin emerged 1-2 weeks post-treatment in C58/J. Furthermore, acute oxytocin decreased motor stereotypy in C58/J and did not induce hypoactivity or anxiolytic-like effects in an open field test. This study demonstrates that oxytocin administration can attenuate social deficits and repetitive behavior in mouse models of ASD, dependent on dose regimen and genotype. These findings provide validation of the BALB/cByJ and C58/J models as useful platforms for screening novel drugs for intervention in ASDs and for elucidating the mechanisms contributing to the prosocial effects of oxytocin.

Pharmacotherapy of impulsive aggression: a quality comparison of controlled studies

The present study assessed the quality of pharmacotherapy trials to treat impulsive aggressive behavior. While a search of the literature found 55 peer-reviewed published studies on the pharmacotherapy of aggression, only 23 met criteria for inclusion in the quality analysis. To be included in this review, the study must have had at least one comparison group to control for placebo effects. The study must have also adequately defined and diagnosed the presence of impulsive aggression or intermittent explosive disorder. The primary reason studies were excluded from the quality analysis was that impulsive aggression was not specifically defined as the behavior being treated (25 of 32, 78%). The results of the quality analysis found that higher quality studies (n=10; 45%) were characterized by a clear definition of impulsive aggression; specific criteria for what constitutes an impulsive aggressive act; the exclusion of participants with neurological disorders, serious mental disorders, and/or low IQ; and information concerning the serum levels of the medication being investigated. A significant weakness found in the literature is the paucity of high quality studies accessing the efficacy of pharmacological agents other than anticonvulsants for the treatment of impulsive aggression.

[Attention deficit syndrome in adults: clinical, psychophysiological features and treatment]

The authors present the results of examination of 34 patients, aged from 18 to 30 years, with attention deficit hyperactivity disorder (ADHD) (ICD-10 item F90.0). The study has shown that inattentive type of ADHD is noted in 50%, combined type in 38.3% and hyperactivity/impulsivity type in 11.7% of patients. Adult patients with ADHD also have a high level of anxiety and asthenic disorders. This study evaluated the efficacy and safety of adaptol in dosage 1500 mg daily during 8 weeks in the treatment of this group of patients. The high efficacy (improvement in 64,7% of cases) and safety of adaptol confirmed by the data of clinical, psychological and neurophysiological studies.

Effects of atomoxetine on locomotor activity and impulsivity in the spontaneously hypertensive rat

Atomoxetine (ATX) is a commonly used non-stimulant treatment for Attention deficit hyperactivity disorder (ADHD). It primarily acts to increase noradrenalin levels; however, at higher doses it can increase dopamine levels. To date there has been no investigations into the effects of orally-administered ATX in the most commonly used model of ADHD, the spontaneously hypertensive rat (SHR). The aim of this study was to describe the effects of doses thought to be selective (0.15 mg/kg) and non-selective (0.3 mg/kg) for noradrenalin on behavioural measures in the SHR. Firstly, we examined the effects of acute and chronic ATX on locomotor activity including sensitisation and cross-sensitisation to amphetamine. Secondly, we measured drug effects on impulsivity using a T-maze delay discounting paradigm. We found no effect of ATX on locomotor activity and no evidence for sensitisation or cross-sensitisation. Furthermore, there were no differences in T-maze performance, indicating no effects on impulsivity at these doses. The absence of behavioural sensitisation supports previous claims of superior safety relative to psychostimulants for the doses administered. There was also no effect on impulsivity; however, we suggest that was confounded by stress specific to SHRs. Implications for future studies, behavioural assessment of SHRs and their use as a model of ADHD are discussed.

Rate dependent effects of acute nicotine on risk taking in young adults are not related to ADHD diagnosis

Beneficial effects of nicotine on cognition and behavioral control are hypothesized to relate to the high rates of cigarette smoking in Attention-Deficit/Hyperactivity Disorder (ADHD). Given that ADHD is associated with both impulsivity and elevated risk taking, we hypothesized that nicotine modulates risk taking, as it does impulsivity. 26 non-smoking young adults (15 controls with normal impulsivity and 11 ADHD with high impulsivity) received 7 mg transdermal nicotine, 20mg oral mecamylamine, and placebo on separate days, followed by the Balloon Analog Risk Task (BART). Statistical analyses found no group differences in baseline risk taking. Reexamination of the data using a median split on baseline risk taking, to create high (HRT) and low (LRT) risk taking groups, revealed significant effects of nicotinic drugs that differed by group. Nicotine reduced risk taking in HRT and mecamylamine increased risk taking in LRT. This finding supports the hypothesis that nicotinic receptor function modulates risk taking broadly, beyond those with ADHD, and is consistent with rate dependent cholinergic modulation of other cognitive functions. Further, the results demonstrate that high impulsivity is separable from high risk taking in young adults with ADHD, supporting the utility of these differential behavioral phenotypes for neurobiological studies.

Dopamine agonists and the suppression of impulsive motor actions in Parkinson disease

The suppression of spontaneous motor impulses is an essential facet of cognitive control that is linked to frontal-BG circuitry. BG dysfunction caused by Parkinson disease (PD) disrupts the proficiency of action suppression, but how pharmacotherapy for PD impacts impulsive motor control is poorly understood. Dopamine agonists improve motor symptoms of PD but can also provoke impulsive-compulsive behaviors (ICB). We investigated whether dopamine agonist medication has a beneficial or detrimental effect on impulsive action control in 38 PD patients, half of whom had current ICB. Participants performed the Simon conflict task, which measures susceptibility to acting on spontaneous action impulses as well as the proficiency of suppressing these impulses. Compared with an off-agonist state, patients on their agonists were no more susceptible to reacting impulsively but were less proficient at suppressing the interference from the activation of impulsive actions. Importantly, agonist effects depended on baseline performance in the off-agonist state; more proficient suppressors off agonist experienced a reduction in suppression on agonist, whereas less-proficient suppressors off agonist showed improved suppression on agonist. Patients with active ICB were actually less susceptible to making fast, impulsive response errors than patients without ICB, suggesting that behavioral problems in this subset of patients may be less related to impulsivity in motor control. Our findings provide further evidence that dopamine agonist medication impacts specific cognitive control processes and that the direction of its effects depends on individual differences in performance off medication.

Effects of acute MDMA intoxication on mood and impulsivity: role of the 5-HT2 and 5-HT1 receptors

MDMA induces positive mood and increases impulse control during intoxication, but only a few studies on the neuropharmacological mechanisms underlying these processes have been conducted. It was hypothesized that pretreatment with 5-HT₁ and 5-HT₂ receptor blockers would prevent MDMA effects on mood and impulsivity. Subjects (N = 17) participated in a double-blind, placebo controlled, within-subject design involving 6 experimental conditions consisting of pretreatment (T1) and treatment (T2). T1 preceded T2 by 30 minutes. T1–T2 combinations were: placebo-placebo, 20 mg pindolol-placebo, 50 mg ketanserin-placebo, placebo-75 mg MDMA, 20 mg pindolol-75 mg MDMA and 50 mg ketanserin-75 g MDMA. Subjects completed a Profile of Mood States (POMS) questionnaire and several impulsivity tasks (Stop signal task, Matching familiar figures task, Cue dependent reversal learning task) at 1.5 hrs post-treatment. MDMA alone increased both positive (vigor, arousal, friendliness, elation, positive mood) and negative affect (anxiety, confusion) as assessed by the POMS questionnaire. MDMA also increased stop reaction time in the Stop signal task and reaction time in the Matching familiar figures task. Pretreatment with ketanserin blocked MDMA effects on positive affect, but not negative affect. Ketanserin did not influence the effects of MDMA on impulsivity. Pindolol did not interact with MDMA on any of the measures. In conclusion, 5-HT₂ receptors mediate positive moods induced by MDMA but not negative moods or impulsivity. 5-HT₁ receptors do not appear to be involved in MDMA effects on mood and impulse control.

[Pharmacological treatment of aggressive impulsive behavior]

This article makes an initially tour of the definitions of violence, aggression and impulsiveness. Violence is a manifestation associated with various aspects of human behavior in different contexts of society and history. It can also be a clinical manifestation of a psychiatric disorder, the behavioral modality of some people with personality disorders, the expression of a somatic disorder, an action exercised by an individual under the influence of substances, as well as the expected reaction of an individual or a group to a specific trigger situation. Aggressiveness means "tendency to act or respond violently", using violent means to things or people and overcome their revulsion to do damage. After that, a brief overview of the different classifications of aggressive behaviour is made, to finish reviewing the bibliography published on the pharmacological treatment of emotional or impulsive aggression with the three main groups of drugs frequently used in clinical practice (antidepressants, mood stabilizers and antipsychotics), and a brief integration scheme is formulated.

Efficacy of guanfacine extended release in the treatment of combined and inattentive only subtypes of attention-deficit/hyperactivity disorder

BACKGROUND

Extended-release guanfacine (GXR) is approved for the treatment of attention-deficit/hyperactivity disorder (ADHD) in children and adolescents aged 6-17 years. This post-hoc analysis further examines the effects of GXR on hyperactivity-impulsivity and inattentiveness.

METHOD

Data from two large double-blind placebo-controlled pivotal trials of GXR in the treatment of ADHD were analyzed. Using the pooled population to provide sufficient sample size and associated statistical power, the impact of GXR treatment on core ADHD symptoms was examined by comparing ADHD Rating Scale IV (ADHD-RS-IV) total scores in the overall GXR and placebo groups in subjects with each of the three ADHD subtypes. ADHD-RS-IV Hyperactivity-Impulsivity and Inattentiveness subscale scores in the overall study population by randomized dose group (vs. placebo) were also examined.

RESULTS

The full analysis set included 631 subjects aged 6-17 years (GXR: n=490; placebo: n=141). Among subjects with the predominantly inattentive subtype of ADHD, differences in least squares (LS) mean reductions from baseline in ADHD-RS-IV total scores were significantly greater in GXR-treated subjects (n=127) than in placebo-treated subjects (n=38) at treatment weeks 3 through 5 and end point (p≤0.020). Among subjects with combined type ADHD, differences in LS mean ADHD-RS-IV total score reductions from baseline were significantly greater in the GXR group (n=354) than in the placebo group (n=100) at treatment weeks 1 through 5 and end point (p≤0.011). The dearth of predominantly hyperactive-impulsive type subjects (n=12) precluded analysis of this subgroup. Each randomized GXR dose group in each trial demonstrated significantly greater reductions from baseline in ADHD-RS-IV Hyperactivity-Impulsivity and Inattentiveness subscale scores than did the respective placebo group at end point (p≤0.05 for all).

CONCLUSIONS

The results support the use of GXR in the treatment of core ADHD symptoms as defined in the American Psychiatric Association Diagnostic and Statistical Manual of Mental Disorders, 4th ed., Text Revision, including hyperactivity, impulsivity, and inattention.

[Impact of treatment with acetylcholinesterase inhibitors, valproic acid and antipsychotics on aggressive behaviour in Alzheimer's type dementia]

Aggressive and impulsive behaviour are common in Alzheimer's dementia. Therapy of these disorders is an important but difficult practical question.

AIM

The purpose of this study was to determine the effect of pharmacological treatment of aggressive behaviour, while taking into account the dynamics of disease progression during observation. In the assessment of treatment acetylcholinesterase inhibitors (IAChE), valproic acid (VA), and antipsychotics were considered.

METHOD

The study was based on a two-year naturalistic observation of nursing homes' residents with a diagnosis of possible Alzheimer's disease (NINCDS/ADRDA criteria) in its mild and moderate stage (at least 12 points in MMSE). Aggressive behaviour was measured by Cohen-Mansfield Agitation Inventory (CMAI), and the severity of dementia by ADAS--Cog. Examination was performed twice: at baseline (0) and after two years of observation (2). All treatment administered during this time has been taken into account. 71 people diagnosed with Alzheimer's disease were enrolled to the observation. The average age was 77.10 (SD = 8.39), the level of cognitive impairment by ADAS--Cog = 20.40 points (SD = 5.24). The second examination was conducted in 43 individuals.

RESULTS

In the group treated with IAChE there was a lesser increase of aggressive and impulsive behaviour in comparison to other persons. The differences between the examination (2) and (0) for the CMAI global scale were, respectively, 2.76 and 9.09 points. Similar results were obtained for subjects treated with VA (1.0 and 8.65). Antipsychotic drugs revealed a similar correlation (3.0 and 8.65), but this has not proven statistically relevant, while in the group treated with antipsychotics a significantly greater progression of dementia was observed.

CONCLUSION

Acetylcholinesterase inhibitors may have beneficial effects on aggressive behaviour in the course of Alzheimer's Disease, similar to that seen with the use of valproic acid and antipsychotics.

Clonidine improved laboratory-measured decision-making performance in abstinent heroin addicts

BACKGROUND

Impulsivity refers to a wide spectrum of actions characterized by quick and nonplanned reactions to external and internal stimuli, without taking into account the possible negative consequences for the individual or others, and decision-making is one of the biologically dissociated impulsive behaviors. Changes in impulsivity may be associated with norepinephrine. Various populations of drug addicts all performed impulsive decision making, which is a key risk factor in drug dependence and relapse. The present study investigated the effects of clonidine, which decreased norepinephrine release through presynaptic alpha-2 receptor activation, on the impaired decision-making performance in abstinent heroin addicts.

METHODOLOGY/PRINCIPAL FINDINGS

Decision-making performance was assessed using the original version of Iowa Gambling Task (IGT). Both heroin addicts and normal controls were randomly assigned to three groups receiving clonidine, 0, 75 µg or 150 µg orally under double blind conditions. Psychiatric symptoms, including anxiety, depression and impulsivity, were rated on standardized scales. Heroin addicts reported higher scores on the Barratt Impulsiveness Scale and exhibited impaired decision-making on the IGT. A single high-dose of clonidine improved the decision-making performance in heroin addicts.

CONCLUSIONS/SIGNIFICANCE

Our results suggest clonidine may have a potential therapeutic role in heroin addicts by improving the impaired impulsive decision-making. The current findings have important implications for behavioral and pharmacological interventions targeting decision-making in heroin addiction.

Chronic atomoxetine treatment during adolescence decreases impulsive choice, but not impulsive action, in adult rats and alters markers of synaptic plasticity in the orbitofrontal cortex

RATIONALE

Impulsivity is a key symptom of attention-deficit hyperactivity disorder (ADHD). The use of the norepinephrine reuptake inhibitor, atomoxetine, to treat ADHD suggests that the activity of the norepinephrine transporter (NET) may be important in regulating impulsive behavior. Many ADHD patients receive chronic drug treatment during adolescence, a time when frontal brain regions important for impulse control are undergoing extensive development.

OBJECTIVES

The current study aimed to determine the effects of chronic atomoxetine treatment during adolescence in rats on two distinct forms of impulsivity in adulthood and whether any behavioral changes were accompanied by alterations in mRNA or protein levels within the frontal cortices.

METHODS

Rats received daily injections of saline or atomoxetine (1 mg/kg) during adolescence (postnatal days 40-54). Two weeks later, animals were trained to perform either the delay-discounting test or the five-choice serial reaction time task (5CSRT).

RESULTS

Adolescent atomoxetine treatment caused a stable decrease in selection of small immediate rewards over larger delayed rewards (impulsive choice) in adulthood, but did not affect premature responding (impulsive action) in the 5CSRT. Chronic atomoxetine treatment also altered the ability of acute atomoxetine to modulate aspects of impulsivity, but did not change the response to d-amphetamine. Ex vivo analysis of brain tissue indicated that chronic atomoxetine decreased phosphorylation of CREB and ERK in the orbitofrontal cortex and decreased mRNA for BDNF and cdk5.

CONCLUSIONS

These data suggest that repeated administration of atomoxetine in adolescence can lead to stable decreases in impulsive choice during adulthood, potentially via modulating development of the orbitofrontal cortex.

Deficits in attentional control: cholinergic mechanisms and circuitry-based treatment approaches

The cognitive control of attention involves maintaining task rules in working memory (or "online"), monitoring reward and error rates, filtering distractors, and suppressing prepotent, and competitive responses. Weak attentional control increases distractibility and causes attentional lapses, impulsivity, and attentional fatigue. Levels of tonic cholinergic activity (changes over tens of seconds or minutes) modulate cortical circuitry as a function of the demands on cognitive control. Increased cholinergic modulation enhances the representation of cues, by augmenting cue-evoked activity in thalamic glutamatergic afferents, thereby increasing the rate of detection. Such cholinergic modulation is mediated primarily via α4β2* nicotinic acetylcholine receptors. Animal experiments and clinical trials in adult patients with ADHD indicate that attentional symptoms and disorders may benefit from drugs that stimulate this receptor. Tonic cholinergic modulation of cue-evoked glutamatergic transients in prefrontal regions is an essential component of the brain's executive circuitry. This circuitry model guides the development of treatments of deficits in attentional control.

Facial self-induced paraffinoma in an elderly woman

A 72-year-old Caucasian woman without remarkable medical history presented with an asymptomatic bilateral periocular swelling, which had been present for 2 months. Physical examination showed symmetric indurated periocular erythematous plaques (Figure 1). Biopsy of a skin lesion revealed aggregates of vacuoles of different sizes (Figure 2) surrounded by a prominent inflammatory infiltrate constituted by macrophages, lymphocytes, neutrophils, and granulomatous foreign body reaction throughout the reticular dermis and hypodermis. These histological findings were consistent with the injection of an oily foreign substance. The patient denied the self-induced nature of the lesions, so she was referred for psychiatric evaluation and admitted having self-injected mineral oil as an impulsive attempt to get attention from her family. She was diagnosed with borderline personality disorder (BPD) and started treatment with oral fluoxetine, showing a rapid decrease of impulsive behavior and anxiety from the second week with a mean dose of 80 mg/d.

Understanding the effects of stimulant medications on cognition in individuals with attention-deficit hyperactivity disorder: a decade of progress

The use of stimulant drugs for the treatment of children with attention-deficit hyperactivity disorder (ADHD) is one of the most widespread pharmacological interventions in child psychiatry and behavioral pediatrics. This treatment is well grounded on controlled studies showing efficacy of low oral doses of methylphenidate and amphetamine in reducing the behavioral symptoms of the disorder as reported by parents and teachers, both for the cognitive (inattention and impulsivity) and non-cognitive (hyperactivity) domains. Our main aim is to review the objectively measured cognitive effects that accompany the subjectively assessed clinical responses to stimulant medications. Recently, methods from the cognitive neurosciences have been used to provide information about brain processes that underlie the cognitive deficits of ADHD and the cognitive effects of stimulant medications. We will review some key findings from the recent literature, and then offer interpretations of the progress that has been made over the past decade in understanding the cognitive effects of stimulant medication on individuals with ADHD.

[Compulsion and impulsion of substance dependence: frontline of pharmacotherapy for craving]

Substance-seeking behavior appears to be compulsive because of unclear motivation, and also appears to be impulsive because of difficulty to be predicted. Compulsivity and impulsivity of substance-dependent individuals are common in unaccountability. This unaccountability is the result form craving for psychoactive substance. If a therapist does not understand it, a treatment session is likely to be punished, not psychotherapeutic. This paper reviews the pharmacotherapies conducted in foreign countries, and suggests the pharmacotherapies which are expected to be introduced into Japan. One of the reasons why psychiatrists tend to be reluctant to treat substance-dependent patients is that there have been no available pharmacotherapies in Japan. Accordingly, pharmacotherapies for substance dependence are required to be developed and established.

Sub-optimal performance in the 5-choice serial reaction time task in rats was sensitive to methylphenidate, atomoxetine and d-amphetamine, but unaffected by the COMT inhibitor tolcapone

Prefrontal cortical dopamine (DA) and norepinephrine (NE) are implicated in multiple aspects of cognitive function assessed via the 5-choice serial reaction time task (5-CSRTT) in rodents. The present studies assessed the effects of the NE reuptake inhibitor atomoxetine (0.5-2.0 mg/kg), the mixed DA/NE reuptake inhibitor methylphenidate (0.1-2.0 mg/kg), the catecholamine releaser D-amphetamine (0.1-1.0 mg/kg) and the catecholamine-o-methyl-transferase (COMT) inhibitor tolcapone (3.0-30.0 mg/kg) in rats that exhibited sub-optimal performance (reduced accuracy: <70% correct) in the 5-CSRTT. Increased ITI durations were associated with increased premature responding. Decreased ITI durations resulted in increased percent omissions, increased perseverative responses and increased response latencies, but had no effects on magazine latencies or percent correct. Atomoxetine decreased premature responding at prolonged ITI durations and methylphenidate decreased percent omissions at low doses (0.1 and 0.5 mg/kg). By contrast, D-amphetamine increased premature and perseverative responding in a dose-dependent manner (0.3-1.0 mg/kg). Finally, tolcapone had no effects on sub-optimal performance in the variable ITI 5-CSRTT. These results suggest minimal potential of tolcapone as a therapeutic agent for ADHD and implicate cortical NE, not DA, in impulsive action.

Pharmacologic dissociation between impulsivity and alcohol drinking in high alcohol preferring mice

BACKGROUND

Impulsivity is genetically correlated with, and precedes, addictive behaviors and alcoholism. If impulsivity or attention is causally related to addiction, certain pharmacological manipulations of impulsivity and/or attention may affect alcohol drinking, and vice versa. The current studies were designed to explore the relationship among impulsivity, drinking, and vigilance in selectively bred High Alcohol Preferring (HAP) mice, a line that has previously demonstrated both high impulsivity and high alcohol consumption. Amphetamine, naltrexone, and memantine were tested in a delay discounting (DD) task for their effects on impulsivity and vigilance. The same drugs and doses were also assessed for effects on alcohol drinking in a 2-bottle choice test.

METHODS

HAP mice were subjected to a modified version of adjusting amount DD using 0.5-second and 10-second delays to detect decreases and increases, respectively, in impulsive responding. In 2 experiments, mice were given amphetamine (0.4, 0.8, or 1.2 mg/kg), naltrexone (3 and 10 mg/kg), and memantine (1 and 5 mg/kg) before DD testing. Another pair of studies used scheduled access, 2-bottle choice drinking to assess effects of amphetamine (0.4, 1.2, or 3.0 mg/kg), naltrexone (3 and 10 mg/kg), and memantine (1 and 5 mg/kg) on alcohol consumption.

RESULTS

Amphetamine dose-dependently reduced impulsivity and vigilance decrement in DD, but similar doses left alcohol drinking unaffected. Naltrexone and memantine decreased alcohol intake at doses that did not affect water drinking but had no effects on impulsivity or vigilance decrement in the DD task.

CONCLUSIONS

Contrary to our hypothesis, none of the drugs tested here, while effective on either alcohol drinking or impulsivity, decreased both behaviors. These findings suggest that the genetic association between drinking and impulsivity observed in this population is mediated by mechanisms other than those targeted by the drugs tested in these studies.

Effects of pramipexole on impulsive choice in male wistar rats

Clinical reports, primarily with Parkinson's disease patients, note an association between the prescribed use of pramipexole (and other direct-acting dopamine agonist medications) and impulse control disorders, particularly pathological gambling. Two experiments examined the effects of acute pramipexole on rats' impulsive choices where impulsivity was defined as selecting a smaller-sooner over a larger-later food reward. In Experiment 1, pramipexole (0.1 to 0.3 mg/kg) significantly increased impulsive choices in a condition in which few impulsive choices were made during a stable baseline. In a control condition, in which impulsive choices predominated during baseline, pramipexole did not significantly change the same rats' choices. Experiment 2 explored a wider range of doses (0.01 to 0.3 mg/kg) using a choice procedure in which delays to the larger-later reinforcer delivery increased across trial blocks within each session. At the doses used in Experiment 1, pramipexole shifted choice toward indifference regardless of the operative delay. At lower doses of pramipexole (0.01 and 0.03 mg/kg), a trend toward more impulsive choice was observed at the 0.03 mg/kg dose. The difference in outcomes across experiments may be due to the more complex discriminations required in Experiment 2, that is, multiple discriminations between changing delays within each session.

A double-blind, placebo-controlled study investigating the effects of omega-3 supplementation in children aged 8-10 years from a mainstream school population

Despite the increased interest in the effects of omega-3 supplementation on children's learning and behaviour, there are a lack of controlled studies of this kind that have utilised a typically developing population. This study investigated the effects of omega-3 supplementation in 450 children aged 8-10 years old from a mainstream school population, using a randomised, double-blind, placebo-controlled design. Participants were supplemented with either active supplements (containing docosahexaenoic acid, DHA and eicosapentaenoic acid, EPA) or a placebo for 16 weeks. Cheek cell fatty acid levels were recorded pre- and post-supplementation and a range of cognitive tests and parent and teacher questionnaires were used as outcome measures. After supplementation, changes in the relationship between omega-6 and omega-3 were significant in the active group. Despite the wide range of cognitive and behavioural outcome measures employed, only three significant differences between groups were found after 16 weeks, one of which was in favour of the placebo condition. Exploring the associations between changes in fatty acid levels and changes in test and questionnaire scores also produced equivocal results. These findings are discussed in relation to previous findings with clinical populations and future implications for research.

Psychiatric use and utility of divalproex sodium in Connecticut prisons

Divalproex sodium (DVX) is used in correctional settings to treat impulsive aggression and mood lability in patients without comorbid bipolar disorder. This review of DVX use in the Connecticut Department of Correction examined the psychiatric diagnostic impression of patients prescribed DVX, the doses used, and the symptomatic and functional change over time. Clinical charts of 168 offenders treated with DVX for one or more months were randomly selected for clinical outcome review and were divided into subgroups based on clinical impression for DVX prescription. In participants without bipolar disorder (44.6%), DVX was used to target impulsivity (14.3%) and mood lability (17.3%). Clinical improvement was noted in bipolar and nonbipolar groups (p < .001). The impulsive/aggressive subgroup was the only nonbipolar subgroup in which DVX yielded clinical benefit. This symptom-driven use of DVX is associated with clinical improvement when impulsive aggression is the target symptom.

Ayahuasca versus violence--a case report

We have limited resources available for the treatment and prevention of violent behavior. The usefulness of the most commonly used medications, namely the selective serotonin-reuptake inhibitor [SSRI] agents for the above purpose is a debated issue in the psychiatric literature. The aim of this case report is to add an ethnopharmacological perspective to the management of human aggression. Particularly, attention is called to the potential prosocial effect of the Amazonian beverage, ayahuasca--a decoctum, which has been used traditionally for multiple medico-religious purposes by numerous indigenous groups of the Upper Amazon--and has been found to be useful in crisis intervention, achieving redemption, as well as eliciting cathartic feelings with moral content.

Similar effects of the selective noradrenaline reuptake inhibitor atomoxetine on three distinct forms of impulsivity in the rat

Atomoxetine is a noradrenaline-specific reuptake inhibitor used clinically for the treatment of childhood and adult attention deficit hyperactivity disorder (ADHD). Studies in human volunteers and patient groups have shown that atomoxetine improves stop-signal reaction time (SSRT) performance, an effect consistent with a reduction in motor impulsivity. However, ADHD is a heterogeneous disorder and it is of interest to determine whether atomoxetine is similarly effective against other forms of impulsivity, as well as the attentional impairment present in certain subtypes of ADHD. The present study examined the effects of atomoxetine on impulsivity using an analogous SSRT task in rats and two additional tests of impulsivity; delay discounting of reward and the five-choice serial reaction time task (5CSRTT), the latter providing an added assessment of sustained visual attention. Atomoxetine produced a significant dose-dependent speeding of SSRT. In addition, atomoxetine produced a selective, dose-dependent decrease in premature responding on the 5CSRTT. Finally, on the delay-discounting task, atomoxetine significantly decreased impulsivity by increasing preference for the large-value reward across increasing delay. These findings conclusively demonstrate that atomoxetine decreases several distinct forms of impulsivity in rats. The apparent contrast of these effects with stimulant drugs such as amphetamine and methylphenidate, which generally act to increase impulsivity on the 5CSRTT, may provide new insights into the mechanisms of action of stimulant and nonstimulant drugs in ADHD.

Effects of atomoxetine and methylphenidate on attention and impulsivity in the 5-choice serial reaction time test

Deficits in attention and response inhibition are apparent across several neurodegenerative and neuropsychiatric disorders for which current pharmacotherapy is inadequate. The 5-choice serial reaction time test (5-CSRTT), which originated from the continuous performance test (CPT) in humans, may serve as a useful translational assay for efficacy in these key behavioral domains. The selective norepinepherine reuptake inhibitor, atomoxetine, represents the first non-stimulant based drug approved for Attention Deficit Hyperactivity Disorder (ADHD) and has replaced methylphenidate (Ritalin) as the first line in pharmacotherapy for the treatment of ADHD. Methylphenidate and atomoxetine have different cortical and sub-cortical neurochemical signatures that could predict differences in cognitive and non-cognitive functions. The present experiments investigated the effects of acute methylphenidate and atomoxetine in male long Evans rats in the 5-choice serial reaction time (5CSRT) test that is hypothesized to serve as a model of vigilance and impulsivity behaviors associated with ADHD. Long Evans rats were trained to perform at 75% correct responses with fewer than 20% missed trials in the 5CSRT test (500 ms stimulus duration, 5 s inter-trial interval (ITI)). By varying the ITI (10, 7, 5, and 4 s) on drug test days, impulsivity (as defined by premature responses) was dramatically increased with a concomitant decrease in attention (percent correct). Subsequently, animals were treated with methylphenidate (2.5 and 5 mg/kg, i.p.) or atomoxetine (0.1, 0.5 and 1 mg/kg, i.p.) using this design. In Experiment 1, treatment with methylphenidate modestly improved overall attention but the highest dose of methylphenidate (5.0 mg/kg) significantly increased impulsivity. In contrast, treatment with atomoxetine induced a marked decrease in impulsivity whilst modestly improving overall attention. Interestingly, no effect was observed on measures of performance (e.g. motivation/sedation) with atomoxetine, whilst moderate hyperactivity (faster overall response latencies; magazine, correct, incorrect) was observed in the methylphenidate group. Those data suggest that the 5CSRT test can be used to differentiate stimulant and non-stimulant pharmacotherapies on measures of impulsivity.

Serotonin transporter polymorphism and fluoxetine effect on impulsiveness and aggression in borderline personality disorder

INTRODUCTION

Impulsiveness and aggressiveness are characteristics of borderline personality disorder and are associated to a serotoninergic system dysfunction. Serotonin transporter polymorphisms have been linked to aggressive and impulsive behaviors. The short allele (S) in depression is associated to a worse response to selective serotonin reuptake inhibitors (SSRI). This study aims to study these polymorphisms to predict the response of aggressive and impulsive behaviors to SSRIs in borderline personality disorder.

METHOD

Fifty-nine patients with DSM-IV borderline personality disorder in accordance with the International Personality Disorder Examination (IPDE) and without axis 1 disease were treated with flexible doses of fluoxetine for 12 weeks. The patients were evaluated with the Overt Aggression Scale Modified (OAS-M) at the beginning and at 2, 4, 8 and 12 weeks of treatment. Polymorphisms L and S of the serotonin transporter promoter region were determined. Response to fluoxetine of the LL carriers versus the S carriers (LS+SS) was compared.

RESULTS

LL carriers had a better response than S carriers in the reduction of total OAS-M scores and on the aggressiveness and irritability components of the OAS-M.

CONCLUSIONS

L-allele carriers responded better to fluoxetine than S carriers, in a similar way as in depression. The S allele may represent a common factor of bad response to SSRI in diseases associated to serotoninergic system dysfunction.

Risperidone exerts potent anti-aggressive effects in a developmentally immature animal model of escalated aggression

BACKGROUND

Risperidone has been shown to be clinically effective for the treatment of aggressive behavior in children, yet no information is available regarding whether risperidone exhibits aggression-specific suppression in preclinical studies that use validated developmentally immature animal models of escalated aggression. Previously, we have shown that exposure to low doses of the psychostimulant cocaine-hydrochloride (.5 mg/kg intraperitoneally) during the majority of pubertal development (postnatal days [P]27-57) generates animals that exhibit a high level of offensive aggression. This study examined whether risperidone exerts selective aggression-suppressing effects by using this pharmacologic animal model of highly escalated offensive aggression.

METHODS

Experimental hamsters were tested for offensive aggression after the acute administration of risperidone (.05-1.0 mg/kg, intraperitoneally).

RESULTS

Risperidone dose-dependently reduced the highly aggressive phenotype, with a significant reduction observed at .1-.2 mg/kg for most aggressive responses measured. Experimental animals treated with higher doses of risperidone (.3-1.0 mg/kg) showed significant reductions in aggression and social interest toward intruders, indicating more general behavioral inhibition.

CONCLUSIONS

These studies provide evidence that risperidone exerts specific aggression-suppressing effects in a developmentally immature animal model of escalated aggression.

Methylphenidate reduces impulsive behaviour in juvenile Wistar rats, but not in adult Wistar, SHR and WKY rats

RATIONALE

Impulsivity is a core symptom of attention deficit/hyperactivity disorder (ADHD). The spontaneously hypertensive rats (SHR) is a strain commonly used as an animal model of ADHD. However, there is no clear evidence that psychostimulants, which are used for treatment of ADHD, reduce impulsivity in SHR. Because ADHD mainly affects children, it may be relevant to study psychostimulants on juvenile animals.

OBJECTIVES

Using tolerance to delay of reward as index of impulsivity, the effects of methylphenidate were assessed in adult SHR, Wistar Kyoto (WKY) and Wistar rats and in juvenile Wistar rats.

MATERIALS AND METHODS

Animals were trained in a T-maze to choose between a small-but-immediate and a large-but-delayed reward. Adult SHR, WKY and Wistar rats were compared for their ability to tolerate a 15-s delay. The effect of methylphenidate on the tolerance to a 30-s delay was studied in adult rats of the three strains and in juvenile (4.5 to 6.5-week-old) Wistar rats.

RESULTS

In adult rats, the waiting ability was lower in SHR than in control strains. Waiting ability was improved by methylphenidate (3 and 5 mg/kg) in juveniles, but not by methylphenidate (3 mg/kg) in adults.

CONCLUSIONS

These data support the idea that SHR are more impulsive than control strains. However, at the dose studied, methylphenidate fails to improve tolerance to delay in adult rats whatever the strain used. The reduction of impulsivity induced by methylphenidate in juvenile Wistar rats indicates that juvenile animals may be suitable for testing the therapeutic potential of drugs intended to the treatment of ADHD in children.

Reduction of impulsivity with amphetamine in an appetitive fixed consecutive number schedule with cue for optimal performance in rats

RATIONALE

Impulsivity is a key feature of many psychopathologies such as mania, personality disorders or attention deficit-hyperactivity disorder (ADHD). Most experimental paradigms assessing impulsive behaviour also require non-specific capacities such as time estimation. This may interact with the measures and mask the beneficial effects of psychostimulants-the most commonly used treatment for ADHD-on impulsivity, given that these drugs speed up the internal clock.

OBJECTIVES

The present experiment investigated the effects of suppressing behaviours non-specific to impulsivity in a fixed consecutive number (FCN) schedule and examined whether amphetamine, previously shown to increase impulsive responses in this task, could have beneficial effects when impulsive responses are promoted.

MATERIALS AND METHODS

Food-deprived rats were trained to press one lever of a two-lever operant chamber eight times before pressing the other lever to obtain food. Premature ending of responses resulted in absence of food delivery and reset the counter. A cue light indicating the required number of presses was present (FCN8(cue)) and removed after training (FCN8). Rats were then trained under an FCN16(cue) schedule to be challenged with d-amphetamine (0.125, 0.25 and 0.5 mg/kg).

RESULTS

The cue improved performances, and similar scores were obtained under FCN16(cue) compared to FCN8. Premature responses under these two conditions were unrelated. Amphetamine reduced impulsive responses in FCN16(cue) at the lower dose.

CONCLUSIONS

Suppression of capacities non-specific to impulsivity in the FCN schedule, associated with conditions that permit the expression of inhibitory deficits, allows the beneficial effects of psychostimulants observed clinically to be evidenced experimentally.

An open-label trial of divalproex extended-release in the treatment of borderline personality disorder

INTRODUCTION

Borderline personality disorder (BPD) is associated with several symptoms, including impulsivity, aggression, and intense unstable affect, which can be targeted with anticonvulsant agents. Divalproex extended-release (ER) is used widely in clinical practice, which leads to the question of its efficacy and tolerability in treating BPD.

METHODS

This study assessed the efficacy and tolerability of divalproex ER in 20 adult outpatients with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition BPD via a 12-week open-label trial. Primary outcome measures included the Clinical Global Impression-Improvement (CGI-I) scale and the Global Assessment Scale. Secondary outcome measures assessed aggression (Aggression Questionnaire, Overt Aggression Scale-Modified); affective disturbance (Affective Intensity Measure, Affective Lability Scale); dissociation (Dissociative Experiences Scale); and general psychopathology (Symptom-Checklist 90-Revised).

RESULTS

Thirteen subjects were male and seven were female with a mean age of 37.0+/-11.3 years. Treatment was associated with statistically significant improvement on the CGI-I, the Global Assessment Scale, the Overt Aggression Scale-Modified irritability subscale, and the Aggression Questionnaire. A trend toward significant improvement was observed on the Affective Intensity Measure. Seven out of 10 completers (70%) were treatment responders, with an endpoint CGI-I of 2 (much improved) or 1 (very much improved). There was no significant decline in affective lability or in dissociation. One participant discontinued treatment due to adverse events.

CONCLUSION

These findings support that divalproex ER is an efficacious and well-tolerated pharmacologic agent for BPD, with the additional advantage of single daily dosing at bedtime. Placebo-controlled trials are needed for replication.

Prefrontal cognitive dysfunction following brainstem lesion

Prefrontal cortex (PFC) dysfunction can lead to impairment in planning and behavioral inhibition, as well as personality changes. As ascending monoaminergic brainstem systems modulate PFC functioning, it is possible that lesions in the brainstem lead to symptoms similar to prefrontal dysfunction. A 29-year-old man developed several cognitive and behavioral symptoms after neurosurgery for resection of a pilocytic astrocytoma in the pontine-mesencephalic area. A careful analysis of symptoms indicated PFC dysfunction that could be attributed to lesions in the ascending monoaminergic brainstem systems. Interestingly, the cognitive symptoms improved after treatment with methylphenidate, which is a drug that modules catecholaminergic neurotransmission, thereby supporting this hypothesis. This is a unique case of PFC dysfunction that may be related to post-operative lesion of the catecholaminergic nuclei in the brainstem.

Endogenous opioid blockade and impulsive responding in alcoholics and healthy controls

The opioid receptor antagonist naltrexone (NTX) is one of few approved treatments for alcoholism, yet the mechanism by which it reduces drinking remains unclear. In rats, NTX reduces morphine-induced impulsive choice bias; however, nothing is known about the drug's effect on discrete aspects of impulsive behavior in humans, such as decision-making and inhibitory control. Here, we used a modified delay discounting procedure to investigate whether NTX improves decision-making or inhibitory control in humans. We measured the effect of acute NTX (50 mg) on choice between smaller sooner (SS) and larger later monetary rewards and on response errors (motor mismatch) in a high conflict condition in a group of abstinent alcoholics (AA) and healthy control subjects (CS). We previously reported that AA selected the SS option significantly more often than did CS in this paradigm. If the choice bias of AA is due to enhanced endogenous opioid signaling in response to potential reward, NTX should reduce such bias in the AA group. We found that NTX did not reliably reduce impulsive choice in the AA group; however, NTX's effect on choice bias across individuals was robustly predictable. NTX's effect on choice bias was significantly correlated with scores on Rotter's Locus of Control (LOC) scale; increasingly internal LOC scores predicted increasing likelihood of impulsive choices on NTX. In addition, we found that NTX significantly enhanced control of motor responses, particularly within the CS group. These results suggest that endogenous opioids may impair response selection during decision-making under conflict, and that NTX's effects on explicit decision-making are personality-dependent. Determining the biological basis of this dependence could have important implications for effective alcoholism treatment.

Efficacy and tolerability of OROS methylphenidate in Korean children with attention-deficit/hyperactivity disorder

This study evaluated the efficacy and tolerability in the initiation treatment of Concerta (OROS methylphenidate HCl) in Korean children with Attention-Deficit/Hyperactivity Disorder (AD/HD). One hundred and nineteen children with AD/HD were entered into a multi-center, open-label, four-week trial. The dosage of Concerta was adjusted by the investigators based on symptoms and safety assessments performed on a weekly basis. The safety of the drug and its efficacy for attention, behavior, and cognitive function were assessed. The primary outcome measures for efficacy were the Parent and Teacher IOWA Conners Rating Scales, Peer Interaction Items, and the Clinical Global Impression Scale. Cognitive tests (Continuous Performance Test, Matched Familiar Figure Test, Verbal Fluency Test, and Trail Making Test) were included as the secondary outcome measures. In most participants, OROS methylphenidate was well tolerated. There were significant improvements in attention, behavior, and function as measured by parents, teachers, and investigators. The benefit of the initiation of OROS methylphenidate in children with AD/HD was shown on the cognitive tests as well. These data provide support for the benefit of the once-daily methylphenidate preparation, Concerta in the treatment of Korean children with AD/HD. Children were initiated safely in this short-term trial, and its effectiveness was evident in the behavioral, as well as neuropsychological measurements.

Modafinil improves attention, inhibitory control, and reaction time in healthy, middle-aged rats

This study examined the effect of the novel psychostimulant modafinil (Provigil) on a variety of cognitive and behavioral measures including associative learning, sustained attention, inhibitory control, and reaction time. Middle-aged female rats (18-20 months old) were administered oral doses of modafinil (0, 8, 32, and 64 mg/kg) and tested in a 3-choice visual discrimination and sustained attention task. Modafinil produced a dose-dependent pattern of improved response accuracy and impulse control (fewer premature responses) and shorter response latencies, without affecting omission errors, motivation or motor control. Although the biochemical mechanism of modafinil is unknown, these results suggest a profile differing from typical psychostimulants (e.g., amphetamine). The implications of these findings for treatment of narcolepsy, ADHD, and various arousal-related disorders are considered. Further research is needed to examine the relative safety, effectiveness, and addictive potential of modafinil, as well as, its effects in comparison with other performance-enhancing drugs (e.g., caffeine, nicotine, and amphetamines).

1H MRS-detectable metabolic brain changes and reduced impulsive behavior in adult rats exposed to methylphenidate during adolescence

Administration of methylphenidate (MPH, Ritalin) to children affected by attention deficit hyperactivity disorder (ADHD) is an elective therapy, which however raises concerns for public health, due to possible persistent neuro-behavioral alterations. We investigated potential long-term consequences at adulthood of MPH exposure during adolescence, by means of behavioral and brain MRS assessment in drug-free state. Wistar adolescent rats (30- to 44-day-old) were treated with MPH (0 or 2 mg/kg once/day for 14 days) and then left undisturbed until adulthood. Levels of impulsive behavior were assessed in the intolerance-to-delay task: Food-restricted rats were tested in operant chambers with two nose-poking holes, delivering one food pellet immediately, or five pellets after a delay whose length was increased over days. MPH-exposed animals showed a less marked shifting profile from the large/late to the small/soon reward, suggesting reduced basal levels of impulsivity, compared to controls. In vivo MRI-guided 1H MRS examinations at 4.7 T in anaesthetised animals revealed long-term biochemical changes in the dorsal striatum (STR), nucleus accumbens (NAcc), and prefrontal cortex (PFC) of MPH-exposed rats. Notably, total creatine and taurine, metabolites respectively involved in bioenergetics and synaptic efficiency, were up-regulated in the STR and conversely down-regulated in the NAcc of MPH-exposed rats. A strong correlation was evident between non-phosphorylated creatine in the STR and behavioral impulsivity. Moreover, unaltered total creatine and increased phospho-creatine/creatine ratio were detected in the PFC, suggesting improved cortical energetic performance. Because of this enduring rearrangement in the forebrain function, MPH-exposed animals may be more efficient when faced with delay of reinforcement. In summary, MPH exposure during adolescence produced enduring MRS-detectable biochemical modifications in brain reward-related circuits, which may account for increased self-control capacity of adult rats.

The efficacy and tolerability of quetiapine versus divalproex for the treatment of impulsivity and reactive aggression in adolescents with co-occurring bipolar disorder and disruptive behavior disorder(s)

OBJECTIVE

The aim of this study was to compare the efficacy and tolerability of quetiapine and divalproex for the treatment of impulsivity and reactive aggression in adolescents with co-occurring bipolar disorder and disruptive behavior disorders.

METHOD

Patients were included in this post hoc analysis if they scored > or = 14 on the Positive and Negative Syndrome Scale (PANSS) Excited Component (EC) and > or = 4 on at least one of the PANSS EC items, had a current diagnosis of bipolar I disorder, manic or mixed episode, and had a lifetime and/or current diagnosis of a disruptive behavioral disorder (DBD) [conduct disorder (CD) or oppositional defiant disorder (ODD)]. Thirty-three (92%) of the 36 subjects with bipolar disorder and DBD met the PANSS EC inclusion criteria. These thirty-three adolescents were randomized to quetiapine (400-600 mg/day) or divalproex (serum level 80-120 microg/mL) for 28 days in this double-blinded study. The primary efficacy measure was change in PANSS Excited Component (EC) score over the study period and at each time point.

RESULTS

Repeated measures analysis of variance (ANOVA) demonstrated statistically significant within-treatment-group effects for divalproex (baseline = 20.6, end point = 13.3, p < 0.0001) and quetiapine (baseline = 18.8, end point = 10.8, p < 0.0001) for the PANSS EC. There were no statistically significant treatment group differences in PANSS EC changes from baseline to end point scores (p = 0.7, d = 0.14). Mixed regression analyses (comparison of slopes, DAY*TREATMENT) revealed that there was no significant difference in the rate of improvement in the PANSS EC scores between the two treatment groups [F(1,31) = 0.78, p = 0.39, d = 0.28].

CONCLUSIONS

Quetiapine and divalproex showed similar efficacy for the treatment of impulsivity and reactive aggression related to co-occurring bipolar and disruptive behavior disorders in adolescents. Quetiapine and divalproex are both useful as monotherapy for the treatment of impulsivity and reactive aggression in adolescents with bipolar and disruptive behavior disorders. Placebo-controlled studies are necessary.

Neuropharmacological modulation of cognition

PURPOSE OF REVIEW

Problems relating to impulsivity, attention, and working memory occur in many neuropsychiatric disorders and represent important targets for pharmacological intervention. The purpose of this article is to review recent neuropharmacological manipulation studies in humans relating to these domains.

RECENT FINDINGS

Serotonin manipulations in healthy volunteers did not affect response inhibition, a cognitive function implicated in impulsive symptoms of attention deficit hyperactivity disorder, trichotillomania, and substance abuse. Serotonin manipulations did affect performance on cognitive tests involving emotionally salient rewards and feedback, suggesting involvement of this neurochemical in affective aspects of impulsivity. Attentional deficits in attention deficit hyperactivity disorder and visuospatial neglect were ameliorated by noradrenergic drugs. Noradrenergic beta-blockade suppressed the encoding of emotionally arousing unpleasant stimuli and reduced amygdala activation in healthy volunteers, with potential implications for posttraumatic stress disorder. Dopaminergic manipulations affected aspects of working memory in healthy volunteers and in patients with Parkinson's disease, with evidence for bidirectional effects depending on baseline performance.

SUMMARY

Recent findings raise exciting prospects for modulating impulsivity, attention, and working memory in a variety of neuropsychiatric disorders. Future studies should use computerized cognitive assessment, measures of functional genetic polymorphisms, and neuroimaging techniques, in order to further elucidate the neurochemical substrates of cognition and optimize treatment approaches.

Efficacy of pharmacotherapy against core traits of borderline personality disorder: meta-analysis of randomized controlled trials

We conducted a meta-analysis of published randomized, placebo-controlled clinical trials that evaluated the effect of pharmacotherapy in patients with borderline personality disorder. Comprehensive searches of the MEDLINE, EMBASE, PsychLIT and Cochrane Central Register of Controlled Trials databases were performed using web-based search engines. Twenty articles, reporting 22 placebo-controlled comparisons, were included in the meta-analysis: eight involved antipsychotics, seven antidepressants and seven mood stabilizers. Antidepressants (four studies, standardized mean difference -0.55, 95% confidence interval -0.92, -0.17) and mood stabilizers (six studies, standardized mean difference -1.74, 95% confidence interval -2.76, -0.73) were effective against affective instability and anger, but did not produce significant benefits against impulsivity and aggression, unstable relationships, suicidality and global functioning. Antipsychotics as a class had a positive effect in terms of impulsivity and aggression (three studies, standardized mean difference -0.31, 95% confidence interval -0.63, -0.003), interpersonal relationships (three studies, standardized mean difference -0.52, 95% confidence interval -0.87, -0.17) and global functioning (seven studies, standardized mean difference -0.56, 95% confidence interval -1.00, -0.11). No difference was observed between pharmacotherapy and placebo in terms of participants leaving the study early. Pharmacotherapy can exert a modest beneficial effect on some core traits of borderline personality disorder.

Atomoxetine for attention-deficit/hyperactivity disorder symptoms in children with pervasive developmental disorders: a pilot study

OBJECTIVE

This pilot study examined the effects of atomoxetine on attention-deficit/hyperactivity disorder (ADHD) symptoms and autistic features in children with pervasive developmental disorders (PDD).

METHOD

Twelve children (aged 6-14 years) with PDD accompanied by ADHD symptoms entered a 10-week open-label study with atomoxetine (1.19 +/- 0.41 mg/kg/day). Response was assessed by using parent and clinician rating scales with change in the ADHD-Rating Scale (ADHDRS) as primary outcome measure.

RESULTS

Atomoxetine reduced ADHD-symptoms as measured by the ADHDRS (44% decrease vs. baseline, p < 0.003), the Conners' Parent Rating Scale-R:S (CPRS-R) (25% in the subscale "Cognitive Problems," p < 0.028; 32% in "Hyperactivity," p < 0.030; and 23% in "ADHD index," p < 0.023). We found a reduction of 21% (p = 0.071) for changes in the subscale "Hyperactivity" of the Aberrant Behavior Checklist (ABC). No change was found in any of the other ABC subscales, nor in the subscale "Oppositional" of the CPRS-R. Five patients (42%) discontinued because of side effects. Gastrointestinal symptoms, irritability, sleep problems, and fatigue were the most frequent side effects.

CONCLUSIONS

These preliminary findings indicate that atomoxetine may be a promising new agent in the treatment of ADHD symptoms in children with PDD. However, children with PDD may have a higher vulnerability for some of the known side-effects of atomoxetine.

Clinical effects and adverse reactions of off-label use of aripiprazole in children and adolescents with developmental disabilities

OBJECTIVE

The aim of this study was to report on the clinical efficacy and side effects of aripiprazole in treating behavioral symptoms of children with a developmental disability (DDs).

DESIGN/METHODS

A retrospective chart review of the first 32 children treated with aripiprazole at an urban clinic for children with DD was conducted.

RESULTS

Ages ranged from 5 to 19 years; 9 (28%) were female. Twenty four had diagnoses within the autistic spectrum and 18 had mental retardation (MR). Other disorders included: attention-deficit/hyperactivity disorder/disruptive behavior disorders (n = 13), mood disorders (n = 7), reactive attachment (n = 2), and sleep disorders (n = 2). Target symptoms included aggression, hyperactivity, impulsivity and, self-injurious behaviors. Twenty eight of the children were switched from another antipsychotic. The mean daily aripiprazole starting dose was 7.1 +/- 0.32 mg (0.17 mg/kg/day) and the mean daily maintenance dose was 10.55 +/- 6.9 mg (0.27 mg/kg/day). Aripiprazole had been used for a period between 6 and 15 months. Improvement in target symptoms was found in 56%. When treating a child with MR, the concomitant presence of an autistic spectrum diagnosis predicted a worse outcome. Side effects were reported in 16 (50%), with the most frequent being sleepiness (n = 6). Mean body mass index (BMI) rose from 22.5 to 24.1 (p = 0.003) over the follow up period, with changes in the BMI z scores. These changes were more pronounced in children younger than 12 years.

CONCLUSIONS

These results with aripiprazole in this difficult-to-treat population suggest that this medication warrants controlled studies of its effectiveness and safety.

A pilot clinical trial of oxcarbazepine in adults with attention-deficit hyperactivity disorder

Despite the increasing recognition of attention-deficit hyperactivity disorder (ADHD) in adults, there is a paucity of controlled pharmacological trials. Recent reports have suggested the potential usefulness of mood stabilizing drugs for ADHD. To this end, the authors completed a pilot study with oxcarbazepine for the treatment of adults with ADHD. This was an open pilot study of oxcarbazepine (300-1,500 mg daily dosage) in adults who met DSM-IV criteria for ADHD. The treatment period was 8 weeks. Of the 9 subjects enrolled in the study (4 men, 5 women), 8 patients could be included in the analysis. At the endpoint of the active treatment, a significantly high proportion of subjects was considered improved while receiving oxcarbazepine. ADHD symptom checklist scores (ADHD-IV rating scale, Conners ADHD adult rating scale, ADHD self-rating [ADHD-SR] scale) showed significant reduction during the treatment period. Treatment with oxcarbazepine was relatively well tolerated; dizziness, sedation and nausea were the most frequently reported adverse effects. The results of this investigation indicate that oxcarbazepine may be a potentially useful agent for the treatment of ADHD in adults. However, placebo-controlled randomized trials are needed to provide evidence.

Efficacy and tolerability of quetiapine in the treatment of borderline personality disorder: A pilot study

OBJECTIVE

Second-generation antipsychotics with a favorable tolerability profile have offered new treatment options for patients with borderline personality disorder. Sparse data are available on the use of quetia-pine in treating this disorder. The aim of the present study is to investigate efficacy and tolerability of quetia-pine in a group of patients with borderline personality disorder.

METHOD

Fourteen consecutive outpatients with a DSM-IV diagnosis of borderline personality disorder were treated for 12 weeks with open-label quetiapine at the dose of 200-400 mg/day. Patients were assessed at baseline, week 4, and week 12 with the Clinical Global Impressions (CGI) severity item, the Brief Psychiatric Rating Scale (BPRS), the Hamilton Rating Scale for Depression (HAM-D), the Hamilton Rating Scale for Anxiety (HAM-A), the Social and Occupational Functioning Assessment Scale (SOFAS), the Borderline Personality Disorder Severity Index (BPDSI), and the Barratt Impulsiveness Scale-version 11 (BIS-11). Adverse effects were evaluated using the Dosage Record and Treatment Emergent Symptom Scale. Statistical analysis was performed with the ANOVA for repeated measures. Significant p values were < or = .05.

RESULTS

Eleven patients completed the study. Three patients (21.4%) dropped out due to excessive somnolence or noncompliance. The mean +/- SD dose of quetia-pine was 309.09 +/- 83.12 mg/day. A significant change was found for the scores of the following scales: CGI severity item, BPRS, HAM-A, SOFAS, BPDSI total score, BPDSI items "impulsivity" and "outbursts of anger," and BIS-11. Common adverse effects were mild-to-moderate somnolence, dry mouth, and dizziness.

CONCLUSION

Initial data suggest that quetiapine is efficacious and well tolerated in treating patients who have borderline personality disorder, particularly when impulsiveness/aggressiveness-related symptoms are prominent. At the moment, no reliable comparison is available in the literature. Double-blind controlled trials are needed to verify these findings.

Safety of high-dose naltrexone treatment: hepatic transaminase profiles among outpatients

OBJECTIVES

This study was carried out to test the hypothesis that the hepatic safety profile of prolonged high-dose oral naltrexone (150 mg/d) is acceptable if over-the-counter analgesic use is restricted.

METHODS

Data from 41 consecutive outpatients with impulse-control disorder receiving naltrexone therapy were analyzed.

RESULTS

The mean treatment duration was 328 days and the mean naltrexone dose was 142 mg/d. Pretherapy/posttherapy mean aspartate transaminase and alanine transaminase levels in the naltrexone-alone group were 21.79/22.54 and 21.74/21.49 U, respectively (all within reference range).

CONCLUSIONS

Although limited in scope, these findings support the hypothesis that long-term use of high-dose oral naltrexone is safe in otherwise healthy patients with impulse-control disorders who restrict their intake of acetaminophen, aspirin, or nonaspirin nonsteroidal anti-inflammatory drugs (NSAID). However, confirming studies are needed.

Reduced attention and increased impulsivity in mice lacking NPY Y2 receptors: Relation to anxiolytic-like phenotype

Neuropeptide (NPY) Y2 receptors play an important role in some anxiety-related and stress-related behaviours in mice. Changes in the level of anxiety can affect some cognitive functions such as memory, attention and inhibitory response control. We investigated the effects of NPY Y2 receptor deletion (Y2(-/-)) in mice on visual attention and response control using the five-choice serial reaction time (5-CSRT) task in which accuracy of detection of a brief visual stimulus across five spatial locations may serve as a valid behavioural index of attentional functioning. Anticipatory and perseverative responses provide a measure of inhibitory response control. During training, the Y2(-/-) mice had lower accuracy (% correct), and made more anticipatory responses. At stimulus durations of 2 and 4s the Y2(-/-) were as accurate as the Y2(+/+) mice but still more impulsive than Y(+/+). At stimulus durations of 0.25 and 0.5s both groups performed worse but the Y2(-/-) mice made significantly fewer correct responses than the Y2(+/+) controls. The anxiolytic drug diazepam at 2mg/kg IP greatly increased the anticipatory responding of Y2(-/-) mice compared to Y2(+/+). The anxiogenic inverse benzodiazepine agonist, FG 7142, at 10mg/kg IP reduced the anticipatory responding of Y2(-/-) but not Y2(+/+) mice. These data suggest that NPY Y2 receptors make an important contribution to mechanisms controlling attentional functioning and "impulsivity". They also show that "impulsivity" of NPY Y2(-/-) mice may depend on their level of anxiety. These findings may help in understanding the pathophysiology of stress disorders and depression.

Essential fatty acids and their role in conditions characterised by impulsivity

There is a biological basis for anticipating a role for the essential fatty acids (EFAs) in the therapeutics of the large number of conditions characterized by impulsivity, hostility and aggression. Abnormalities in these constructs have been linked to dysfunction of several monoaminergic systems, 5-hydroxytryptamine (5-HT) in particular. The EFAs ameliorate the function of these systems and also act through a number of other mechanisms. While limited in volume, a number of EFA supplementation studies support their role in the treatment of such conditions. This paper summarises the literature in terms of epidemiology, clinical science and therapeutics in clinical and non-clinical populations.

Histamine H3 Receptor Antagonists: Preclinical Promise for Treating Obesity and Cognitive Disorders

The histamine H3 receptor is an attractive G protein-coupled receptor drug target that regulates neurotransmission in the central nervous system and plays a role in cognitive and homeostatic functions. Drug discovery efforts by numerous pharmaceutical companies have focused on the preclinical development of H3 receptor antagonists for the potential treatment of attention-deficit hyperactivity disorder, dementias, schizophrenia, as well as obesity and sleep disorders. This receptor exhibits molecular, pharmacological, and functional heterogeneity that informs the preclinical development of effective antagonists. Herein, we describe the biological and chemical implications for developing H3 receptor antagonists and their therapeutic potential as disclosed through animal models of cognition, sleep, and obesity.