Psychopathology Induced by “Speed Drugs”

Modeling dopamine dysfunction in autism spectrum disorder: From invertebrates to vertebrates

Autism Spectrum Disorder (ASD) is a highly heterogeneous neurodevelopmental disorder characterized by deficits in social communication and by patterns of restricted interests and/or repetitive behaviors. The Simons Foundation Autism Research Initiative's Human Gene and CNV Modules now list over 1000 genes implicated in ASD and over 2000 copy number variant loci reported in individuals with ASD. Given this ever-growing list of genetic changes associated with ASD, it has become evident that there is likely not a single genetic cause of this disorder nor a single neurobiological basis of this disorder. Instead, it is likely that many different neurobiological perturbations (which may represent subtypes of ASD) can result in the set of behavioral symptoms that we called ASD. One such of possible subtype of ASD may be associated with dopamine dysfunction. Precise regulation of synaptic dopamine (DA) is required for reward processing and behavioral learning, behaviors which are disrupted in ASD. Here we review evidence for DA dysfunction in ASD and in animal models of ASD. Further, we propose that these studies provide a scaffold for scientists and clinicians to consider subcategorizing the ASD diagnosis based on the genetic changes, neurobiological difference, and behavioral features identified in individuals with ASD.

Psychostimulant use disorder emphasizing methamphetamine and the opioid -dopamine connection: Digging out of a hypodopaminergic ditch

BACKGROUND

Approved food and drug administration (FDA) medications to treat Psychostimulant Use Disorder (PUD) are needed. Both acute and chronic neurological deficits related to the neurophysiological effects of these powerfully addictive drugs can cause stroke and alterations in mood and cognition.

OBJECTIVE

This article presents a brief review of the psychiatric and neurobiological sequelae of methamphetamine use disorder, some known neurogenetic associations impacted by psychostimulants, and explores treatment modalities and outcomes.

HYPOTHESIS

The authors propose that gentle D2 receptor stimulation accomplished via some treatment modalities can induce dopamine release, causing alteration of D2-directed mRNA and thus enhanced function of D2 receptors in the human. This proliferation of D2 receptors, in turn, will induce the attenuation of craving behavior, especially in genetically compromised high-risk populations.

DISCUSSION

A better understanding of the involvement of molecular neurogenetic opioid, mesolimbic dopamine, and psychostimulant connections in "wanting" supports this hypothesis. While both scientific and, clinical professionals search for an FDA approved treatment for PUD the induction of dopamine homeostasis, via activation of the brain reward circuitry, offers treatment for underlying neurotransmitter functional deficits, potential prophylaxis, and support for recovery efforts.

CONCLUSION

Dopamine regulation may help people dig out of their hypodopaminergia ditch.

Apathy and Impulse Control Disorders: Yin & Yang of Dopamine Dependent Behaviors

Neuropsychiatric symptoms are common non-motor symptoms in Parkinson's disease (PD). Apathy and impulse control disorders (ICD) are two opposite motivational expressions of a continuous behavioural spectrum involving hypo- and hyperdopaminergia. Both syndromes share pathological (decreased vs increased) dopamine receptor stimulation states. Apathy belongs to the spectrum of hypodopaminergic symptoms together with anhedonia, anxiety and depression. Apathy is a key symptom of PD which worsens with disease progression. Animal models, imaging and pharmacological studies concur in pointing out dopaminergic denervation in the aetiology of parkinsonian apathy with a cardinal role of decreased tonic D2/D3 receptor stimulation. ICDs are part of the hyperdopaminergic behavioural spectrum, which also includes punding, and dopamine dysregulation syndrome (DDS), which are all related to non-physiological dopaminergic stimulation induced by antiparkinsonian drugs. According to clinical data tonic D2/D3 receptor stimulation can be sufficient to induce ICDs. Clinical observations in drug addiction and PD as well as data from studies in dopamine depleted rodents provide hints allowing to argue that both pulsatile D1 and D2 receptor stimulation and the severity of dopaminergic denervation are risk factors to develop punding behavior and DDS. Imaging studies have shown that the brain structures involved in drug addiction are also involved in hyperdopaminergic behaviours with increase of bottom-up appetitive drive and decrease in prefrontal top down behavioural control.

Neurobehavioral Sequelae of Psychostimulant Abuse

Psychostimulants are a heterogeneous group of drugs known not only for its arousal and motor activity enhancing effects but also for its high risk of abuse. In susceptible individuals, chronic use can cause addiction leading to devastating physical, psychological, and social health consequences. This chapter will focus on the neurobehavioral consequences of psychostimulant abuse. Different models and theories of addiction and possible underlying mechanisms as well as changed in decision making on neuropsychological tasks have been discussed. Prevention and early behavioral intervention are of paramount importance given the lack of approved drug therapies for these patients.

Pathophysiology of L-dopa-induced motor and non-motor complications in Parkinson's disease

Involuntary movements, or dyskinesia, represent a debilitating complication of levodopa (L-dopa) therapy for Parkinson's disease (PD). L-dopa-induced dyskinesia (LID) are ultimately experienced by the vast majority of patients. In addition, psychiatric conditions often manifested as compulsive behaviours, are emerging as a serious problem in the management of L-dopa therapy. The present review attempts to provide an overview of our current understanding of dyskinesia and other L-dopa-induced dysfunctions, a field that dramatically evolved in the past twenty years. In view of the extensive literature on LID, there appeared a critical need to re-frame the concepts, to highlight the most suitable models, to review the central nervous system (CNS) circuitry that may be involved, and to propose a pathophysiological framework was timely and necessary. An updated review to clarify our understanding of LID and other L-dopa-related side effects was therefore timely and necessary. This review should help in the development of novel therapeutic strategies aimed at preventing the generation of dyskinetic symptoms.

Cocaine-induced psychotic disorders: presentation, mechanism, and management

Cocaine, the third mostly commonly used illicit drug in the United States, has a wide range of neuropsychiatric effects, including transient psychotic symptoms. When psychotic symptoms occur within a month of cocaine intoxication or withdrawal, the diagnosis is cocaine-induced psychotic disorder (CIPD). Current evidence suggests those with CIPD are likely to be male, have longer severity and duration of cocaine use, use intravenous cocaine, and have a lower body mass index. Differentiating CIPD from a primary psychotic disorder requires a detailed history of psychotic symptoms in relation to substance use and often a longitudinal assessment. Treatment includes providing a safe environment, managing agitation and psychosis, and addressing the underlying substance use disorder. This review begins with a clinical case and summarizes the literature on CIPD, including clinical presentation, differential diagnosis, mechanism and predictors of illness, and treatment.

Neurologic manifestations of chronic methamphetamine abuse

The drug with perhaps the greatest impact on the practice of Psychiatry is Methamphetamine. By increasing the extracellular concentrations of dopamine while slowly damaging the dopaminergic neurotransmission, Meth is a powerfully addictive drug whose chronic use preferentially causes psychiatric complications. Chronic Meth users have deficits in memory and executive functioning as well as higher rates of anxiety, depression, and most notably psychosis. It is because of addiction and chronic psychosis from Meth abuse that the Meth user is most likely to come to the attention of the practicing Psychiatrist/Psychologist. Understanding the chronic neurologic manifestations of Meth abuse will better arm practitioners with the diagnostic and therapeutic tools needed to make the Meth epidemic one of historical interest only.

Cannabinoid receptors mediate methamphetamine induction of high frequency gamma oscillations in the nucleus accumbens

Patients suffering from amphetamine-induced psychosis display repetitive behaviors, partially alleviated by antipsychotics, which are reminiscent of rodent stereotypies. Due to recent evidence implicating endocannabinoid involvement in brain disorders, including psychosis, we studied the effects of endocannabinoid signaling on neuronal oscillations of rats exhibiting methamphetamine stereotypy. Neuronal network oscillations were recorded with multiple single electrode arrays aimed at the nucleus accumbens of freely-moving rats. During the experiments, animals were dosed intravenously with the CB1 receptor antagonist rimonabant (0.3 mg/kg) or vehicle followed by an ascending dose regimen of methamphetamine (0.01, 0.1, 1, and 3 mg/kg; cumulative dosing). The effects of drug administration on stereotypy and local gamma oscillations were evaluated. Methamphetamine treatment significantly increased high frequency gamma oscillations (∼80 Hz). Entrainment of a subpopulation of nucleus accumbens neurons to high frequency gamma was associated with stereotypy encoding in putative fast-spiking interneurons, but not in putative medium spiny neurons. The observed ability of methamphetamine to induce both stereotypy and high frequency gamma power was potently disrupted following CB1 receptor blockade. The present data suggest that CB1 receptor-dependent mechanisms are recruited by methamphetamine to modify striatal interneuron oscillations that accompany changes in psychomotor state, further supporting the link between endocannabinoids and schizophrenia spectrum disorders.

Breaking the loop: oxytocin as a potential treatment for drug addiction

Drug use typically occurs within a social context, and social factors play an important role in the initiation, maintenance and recovery from addictions. There is now accumulating evidence of an interaction between the neural substrates of affiliative behavior and those of drug reward, with a role for brain oxytocin systems in modulating acute and long-term drug effects. Early research in this field indicated that exogenous oxytocin administration can prevent development of tolerance to ethanol and opiates, the induction of stereotyped, hyperactive behavior by stimulants, and the withdrawal symptoms associated with sudden abstinence from drugs and alcohol. Additionally, stimulation of endogenous oxytocin systems is a key neurochemical substrate underlying the prosocial and empathogenic effects of party drugs such as MDMA (Ecstasy) and GHB (Fantasy). Brain oxytocin systems exhibit profound neuroplasticity and undergo major neuroadaptations as a result of drug exposure. Many drugs, including cocaine, opiates, alcohol, cannabis, MDMA and GHB cause long-term changes in markers of oxytocin function and this may be linked to enduring deficits in social behavior that are commonly observed in laboratory animals repeatedly exposed to these drugs. Very recent preclinical studies have illustrated a remarkable ability of exogenously delivered oxytocin to inhibit stimulant and alcohol self-administration, to alter associated drug-induced changes in dopamine, glutamate and Fos expression in cortical and basal ganglia sites, and to prevent stress and priming-induced relapse to drug seeking. Oxytocin therefore has fascinating potential to reverse the corrosive effects of long-term drugs abuse on social behavior and to perhaps inoculate against future vulnerability to addictive disorders. The results of clinical studies examining intranasal oxytocin effects in humans with drug use disorders are eagerly awaited. This article is part of a Special Issue entitled Oxytocin, Vasopressin, and Social Behavior.

The melanin-concentrating hormone (MCH) system modulates behaviors associated with psychiatric disorders

Deficits in sensorimotor gating measured by prepulse inhibition (PPI) of the startle have been known as characteristics of patients with schizophrenia and related neuropsychiatric disorders. PPI disruption is thought to rely on the activity of the mesocorticolimbic dopaminergic system and is inhibited by most antipsychotic drugs. These drugs however act also at the nigrostriatal dopaminergic pathway and exert adverse locomotor responses. Finding a way to inhibit the mesocorticolimbic- without affecting the nigrostriatal-dopaminergic pathway may thus be beneficial to antipsychotic therapies. The melanin-concentrating hormone (MCH) system has been shown to modulate dopamine-related responses. Its receptor (MCH1R) is expressed at high levels in the mesocorticolimbic and not in the nigrostriatal dopaminergic pathways. Interestingly a genomic linkage study revealed significant associations between schizophrenia and markers located in the MCH1R gene locus. We hypothesize that the MCH system can selectively modulate the behavior associated with the mesocorticolimbic dopamine pathway. Using mice, we found that central administration of MCH potentiates apomorphine-induced PPI deficits. Using congenic rat lines that differ in their responses to PPI, we found that the rats that are susceptible to apomorphine (APO-SUS rats) and exhibit PPI deficits display higher MCH mRNA expression in the lateral hypothalamic region and that blocking the MCH system reverses their PPI deficits. On the other hand, in mice and rats, activation or inactivation of the MCH system does not affect stereotyped behaviors, dopamine-related responses that depend on the activity of the nigrostriatal pathway. Furthermore MCH does not affect dizocilpine-induced PPI deficit, a glutamate related response. Thus, our data present the MCH system as a regulator of sensorimotor gating, and provide a new rationale to understand the etiologies of schizophrenia and related psychiatric disorders.

Neurologic manifestations of chronic methamphetamine abuse

Methamphetamine abuse has reached epidemic proportions in the United States. The repetitive use of methamphetamine causes massive and sustained elevations in central monoamines. These elevations, particularly in dopamine, can cause changes in the function of the central nervous system that can manifest as a variety of neurologic disorders. This article focuses on these disorders, such as neurocognitive disorders and mental illness, including drug-induced psychosis; motor disorders, including the possible risk of Parkinson's disease, the development of choreoathetoid movements, and punding; and changes in the physical appearance of the methamphetamine users, including dental caries.

Systems-scale analysis reveals pathways involved in cellular response to methamphetamine

Background

Methamphetamine (METH), an abused illicit drug, disrupts many cellular processes, including energy metabolism, spermatogenesis, and maintenance of oxidative status. However, many components of the molecular underpinnings of METH toxicity have yet to be established. Network analyses of integrated proteomic, transcriptomic and metabolomic data are particularly well suited for identifying cellular responses to toxins, such as METH, which might otherwise be obscured by the numerous and dynamic changes that are induced.

Methodology/Results

We used network analyses of proteomic and transcriptomic data to evaluate pathways in Drosophila melanogaster that are affected by acute METH toxicity. METH exposure caused changes in the expression of genes involved with energy metabolism, suggesting a Warburg-like effect (aerobic glycolysis), which is normally associated with cancerous cells. Therefore, we tested the hypothesis that carbohydrate metabolism plays an important role in METH toxicity. In agreement with our hypothesis, we observed that increased dietary sugars partially alleviated the toxic effects of METH. Our systems analysis also showed that METH impacted genes and proteins known to be associated with muscular homeostasis/contraction, maintenance of oxidative status, oxidative phosphorylation, spermatogenesis, iron and calcium homeostasis. Our results also provide numerous candidate genes for the METH-induced dysfunction of spermatogenesis, which have not been previously characterized at the molecular level.

Conclusion

Our results support our overall hypothesis that METH causes a toxic syndrome that is characterized by the altered carbohydrate metabolism, dysregulation of calcium and iron homeostasis, increased oxidative stress, and disruption of mitochondrial functions.

Key role of striatal cholinergic interneurons in processes leading to arrest of motor stereotypies

Motor stereotypy is a key symptom of various disorders such as Tourette's syndrome and punding. Administration of nicotine or cholinesterase inhibitors is effective in treating some of these symptoms. However, the role of cholinergic transmission in motor stereotypy remains unknown. During strong cocaine-induced motor stereotypy, we showed earlier that increased dopamine release results in decreased acetylcholine release in the territory of the dorsal striatum related to the prefrontal cortex. Here, we investigated the role of striatal cholinergic transmission in the arrest of motor stereotypy. Analysis of N-methyl-d-aspartic acid-evoked release of dopamine and acetylcholine during declining intensity of motor stereotypy revealed a dissociation between dopamine and acetylcholine release. Whereas dopamine release remained increased, the inhibition of acetylcholine release decreased, mirroring the time course of motor stereotypy. Furthermore, pharmacological treatments restoring striatal acetylcholine release (raclopride, dopamine D2 antagonist; intraperitoneal or local injection in prefrontal territory of the dorsal striatum) rapidly stopped motor stereotypy. In contrast, pharmacological treatments that blocked the post-synaptic effects of acetylcholine (scopolamine, muscarinic antagonist; intraperitoneal or striatal local injection) or induced degeneration of cholinergic interneurons (AF64A, cholinergic toxin) in the prefrontal territory of the dorsal striatum robustly prolonged the duration of strong motor stereotypy. Thus, we propose that restoration of cholinergic transmission in the prefrontal territory of the dorsal striatum plays a key role in the arrest of motor stereotypy.

Insights into pathophysiology of punding reveal possible treatment strategies

Punding is a stereotyped behavior characterized by an intense fascination with a complex, excessive, nongoal oriented, repetitive activity. Men tend to repetitively tinker with technical equipment such as radio sets, clocks, watches and car engines, the parts of which may be analyzed, arranged, sorted and cataloged but rarely put back together. Women, in contrast, incessantly sort through their handbags, tidy continuously, brush their hair or polish their nails. Punders are normally aware of the inapposite and obtuse nature of the behavior; however, despite the consequent self-injury, they do not stop such behavior. The most common causes of punding are dopaminergic replacement therapy in patients affected by Parkinson's disease (PD) and cocaine and amphetamine use in addicts. The vast majority of information about punding comes from PD cases. A critical review of these cases shows that almost all afflicted patients (90%) were on treatment with drugs acting mainly on dopamine receptors D1 and D2, whereas only three cases were reported in association with selective D2 and D3 agonists. Epidemiological considerations and available data from animal models suggest that punding, drug-induced stereotypies, addiction and dyskinesias all share a common pathophysiological process. Punding may be related to plastic changes in the ventral and dorsal striatal structures, including the nucleus accumbens, and linked to psychomotor stimulation and reward mechanisms. Possible management guidelines are proposed.

Dopamine dysregulation syndrome: an overview of its epidemiology, mechanisms and management

Dopamine dysregulation syndrome (DDS) is a relatively recently described iatrogenic disturbance that may complicate long-term symptomatic therapy of Parkinson's disease. Patients with DDS develop an addictive pattern of dopamine replacement therapy (DRT) use, administering doses in excess of those required to control their motor symptoms. The prevalence of DDS in patients attending specialist Parkinson's disease centres is 3-4%. Amongst the behavioural disturbances associated with DDS are punding, which is a complex stereotyped behaviour, and impulse control disorders (ICDs), such as pathological gambling, hypersexuality, compulsive shopping and compulsive eating. We review the risk factors and potential mechanisms for the development of DDS, including personality traits, potential genetic influences and Parkinson's disease-related cognitive deficits. Impulsive personality traits are prominent in patients developing DDS, and have been previously associated with the development of substance dependence. Candidate genes affecting the dopamine 'D(2)-like' receptor family have been associated with impulsive personality traits in addition to drug and nondrug addictions. Impaired decision making is implicated in addictive behaviours, and decision-making abilities can be influenced by dopaminergic medications. In Parkinson's disease, disruption of the reciprocal loops between the striatum and structures in the prefrontal cortex following dopamine depletion may predispose to DDS. The role of DRT in DDS is discussed, with particular reference to models of addiction, suggesting that compulsive drug use is due to progressive neuroadaptations in dopamine projections to the accumbens-related circuitry. Evidence for neuroadaptations and sensitization occurring in DDS include enhanced levodopa-induced ventral striatal dopamine release. Levodopa is still considered the most potent trigger for DDS in Parkinson's disease, but subcutaneous apomorphine and oral dopamine agonists may also be responsible. In the management of DDS, further research is needed to identify at-risk groups, thereby facilitating more effective early intervention. Therefore, an increased awareness of the syndrome amongst treating physicians is vital. Medication reduction strategies are employed, particularly with regard to avoiding rapidly acting 'booster' DRT formulations. Psychosocial treatments, including cognitive-behavioural therapy, have been beneficial in treating substance use disorders and ICDs in non-Parkinson's disease patients, but there are currently no published trials of psychological interventions in DDS. Further studies are also required to identify factors that can predict those patients with DDS or ICDs who will derive benefit from surgical interventions such as deep brain stimulation.

Parkin deletion causes cerebral and systemic amyloidosis in human mutated tau over-expressing mice

Deposition of proteins leading to amyloid takes place in some neurodegenerative diseases such as Alzheimer's disease and Huntington's disease. Mutations of tau and parkin proteins produce neurofibrillary abnormalities without deposition of amyloid. Here we report that mature, parkin null, over-expressing human mutated tau (PK(-/-)/Tau(VLW)) mice have altered behaviour and dopamine neurotransmission, tau pathology in brain and amyloid deposition in brain and peripheral organs. PK(-/-)/Tau(VLW) mice have abnormal behaviour and severe drop out of dopamine neurons in the ventral midbrain, up to 70%, at 12 months and abundant phosphorylated tau positive neuritic plaques, neuro-fibrillary tangles, astrogliosis, microgliosis and plaques of murine beta-amyloid in the hippocampus. PK(-/-)/Tau(VLW) mice have organomegaly of the liver, spleen and kidneys. The electron microscopy of the liver confirmed the presence of a fibrillary protein deposits with amyloid characteristics. There is also accumulation of mouse tau in hepatocytes. These mice have lower levels of CHIP-HSP70, involved in the proteosomal degradation of tau, increased oxidative stress, measured as depletion of glutathione which, added to lack of parkin, could trigger tau accumulation and amyloidogenesis. This model is the first that demonstrates beta-amyloid deposits caused by over-expression of tau and without modification of the amyloid precursor protein, presenilins or secretases. PK(-/-)/Tau(VLW) mice provide a link between the two proteins more important for the pathogenesis of Alzheimer disease.

Cocaine addiction: from habits to stereotypical-repetitive behaviors and punding

"Punding" is a stereotypical motor behavior characterized by an intense fascination with repetitive handling and examining of objects. Since its first description in amphetamine and cocaine addicts, data on punding has only derived from studies performed in patients with Parkinson's disease (PD). Punding is classifiable as the most severe form of Repetitive Reward-Seeking Behaviours (RRSB) syndromes. The aim of this study was to investigate the occurrence and phenomelogy of RRSB acutely induced by cocaine in order to determine the prevalence, severity and distinctive features discriminating "punders" from "non-punders". A consecutive sample of 50 cocaine addicts received a clinical psychiatric interview. RRSB diagnosis and severity were assessed using a modified version of a previous published questionnaire designed to identify punding in patients with PD. In the present series, 38% of the cocaine addicts met the proposed diagnostic criteria for a RRSB and 8% were considered punders. Subjects with vs. without RRSB did not differ in terms of sex ratio, age, education, occupation, predisposing habits, duration of cocaine use, hours of sleep, comorbid psychiatric disorders, and concomitant use of other drugs. These results and the observation that in the majority of cases RRSB started soon after first drug intake, strongly suggest that an underlying unknown predisposition led to the development of these behaviors. In conclusion, RRSB and punding is much more common than has been described previously and the resultant social disability is often overlooked.

Behavioral genetic contributions to the study of addiction-related amphetamine effects

Amphetamines, including methamphetamine, pose a significant cost to society due to significant numbers of amphetamine-abusing individuals who suffer major health-related consequences. In addition, methamphetamine use is associated with heightened rates of violent and property-related crimes. The current paper reviews the existing literature addressing genetic differences in mice that impact behavioral responses thought to be relevant to the abuse of amphetamine and amphetamine-like drugs. Summarized are studies that used inbred strains, selected lines, single-gene knockouts and transgenics, and quantitative trait locus (QTL) mapping populations. Acute sensitivity, neuroadaptive responses, rewarding and conditioned effects are among those reviewed. Some gene mapping work has been accomplished, and although no amphetamine-related complex trait genes have been definitively identified, translational work leading from results in the mouse to studies performed in humans is beginning to emerge. The majority of genetic investigations have utilized single-gene knockout mice and have concentrated on dopamine- and glutamate-related genes. Genes that code for cell support and signaling molecules are also well-represented. There is a large behavioral genetic literature on responsiveness to amphetamines, but a considerably smaller literature focused on genes that influence the development and acceleration of amphetamine use, withdrawal, relapse, and behavioral toxicity. Also missing are genetic investigations into the effects of amphetamines on social behaviors. This information might help to identify at-risk individuals and in the future to develop treatments that take advantage of individualized genetic information.

Punding prevalence in Parkinson's disease

The purpose of this study was to determine punding prevalence in an ambulatory Parkinson's disease (PD) population. We conducted a patient-and-caregiver-completed punding survey in 373 consecutive patients in an academic ambulatory center. Completion rate was 78%. Only four patients were identified as punding. Patients did not retain insight to their behavior. Forty patients with high-dose levodopa monotherapy or levodopa and dopamine agonist treatment had physician-administered interview. None had punding. Punding incidence was low in this patient group (1.4%) in contrast with previous reports of 14%. Despite the low incidence, this behavior is disruptive and should be carefully elicited by physicians caring for Parkinson's disease patients.

Punding as a Complication of Brain Stem Stroke?

Background and Purpose— Stereotyped motor behaviors, known as “punding,” originally described among amphetamine abusers have only recently been reported in Parkinson disease associated with both pro-(eg, levodopa) or anti-(eg, quetiapine) dopaminergic therapy. We describe a non–Parkinson disease case of nonpharmacologically induced punding as a complication of a brain stem cardiovascular accident.

Summary of Case— A 54-year-old man, after an episode of brain stem cardiovascular accident secondary to basilar artery thrombosis, was noted to endlessly purchase and hoard food items and to write, copy and organize recipes. His activity was excessive, disruptive and affected his interaction with family members. The patient’s punding behaviors significantly improved with an increased dose of sertraline from 100 mg to 150 mg per day.

Conclusion— Our patient’s presentation was most consistent with punding, but interestingly was not a result of dopaminergic therapy. Moreover, improvement of his behavior was noted with a selective serotonin reuptake inhibitor, further questioning the dopaminergic hypothesis of punding.

The effect of drug abuse on body mass index in Hispanics with and without HIV infection

Objective:

There is a widely held view that the lower weight of drug abusers is attributable to diet. However, many studies on the dietary intake of drug abusers have failed to find energy insufficiency, while non-dietary factors have rarely been examined. The purpose of this study was to examine non-dietary factors that could affect the weight of drug abusers with and without HIV infection.

Design:

Participants were recruited into one of three groups: HIV-positive drug abusers (n=85), HIV-negative drug abusers (n=102) and HIV-positive persons who do not use drugs (‘non-drug abusers’, n=98). Non-dietary factors influencing weight included infection with HIV and/or hepatitis, malabsorption, resting energy expenditure and physical activity.

Setting:

The baseline data from a prospective cohort study of the role of drug abuse in HIV/AIDS weight loss conducted in Boston, USA.

Subjects:

The first 286 participants to enrol in the study.

Results:

HIV-positive drug abusers had a body mass index (BMI) that was significantly lower than that of HIV-positive non-drug abusers. The differences in weight were principally differences in fat. In the men, cocaine abuse, either alone or mixed with opiates, was associated with lower BMI, while strict opiate abuse was not. Infection with HIV or hepatitis, intestinal malabsorption, resting energy expenditure and physical activity, as measured in this study, did not explain the observed differences in weight and BMI.

Conclusions:

Drug abuse, and especially cocaine abuse, was associated with lower weight in men. However, infection with HIV and/or hepatitis, malabsorption and resting energy expenditure do not explain these findings.

Does antipsychotic withdrawal provoke psychosis? Review of the literature on rapid onset psychosis (supersensitivity psychosis) and withdrawal-related relapse

OBJECTIVE

To examine the evidence that discontinuation of long-term antipsychotic medication, including clozapine, may provoke a psychotic episode.

METHOD

Databases were searched and citations scrutinised.

RESULTS

Evidence for a rapid onset psychosis (supersensitivity psychosis) following clozapine withdrawal was found and weaker evidence that this might occur with some other antipsychotic drugs. Some cases were reported in people without a psychiatric history. It appears that the psychosis may be a feature of drug withdrawal rather than the re-emergence of an underlying illness, at least in some patients. Meta-analyses of withdrawal studies have suggested that antipsychotic discontinuation may also increase the risk of relapse over and above the risk because of the underlying disorder, but not all individual studies show this effect. Mechanisms may relate to brain adaptations to long-term drug use but data are sparse.

CONCLUSION

These effects require further urgent research. Interventions to reduce morbidity after drug withdrawal need to be developed.

Punding and computer addiction in Parkinson's disease

Punding is a stereotypical behavior in which there is an intense fascination with repetitive handling and examining of mechanical objects, such as taking apart watches and radios or arranging common objects (lining up pebbles, rocks, or other small objects). This disabling condition, different from both obsessive-compulsive disorder and mania, is probably underreported. Punding is thought to be related to dopaminergic stimulation, although only a few observations of this condition in patients with Parkinson's disease (PD) under therapy has been reported. We report a man with PD who developed an unusual, severe, repetitive behavior characterized by spending most of his time on his computer; this abnormal behavior was concomitant with the introduction of L-dopa (400 mg per day) and was not associated to a pattern of chronic inappropriate overuse of dopaminergic medication or other psychiatric symptoms. The patient had the feeling he was forced into a disruptive and unproductive behavior, and he made several attempts to quit without succeeding.

Why is it so difficult to stop psychiatric drug treatment?

In this paper, I argue that the problems that occur after discontinuation or reduction of long-term psychiatric drug treatment may be caused by the process of drug withdrawal itself, rather than representing the course of the underlying illness. Adverse effects induced by discontinuation of psychiatric medication include: (1) a somatic discontinuation syndrome that includes psychological symptoms which may be mistaken for relapse, (2) a rapid onset psychotic reaction after withdrawal of both conventional neuroleptic drugs and some atypicals, notably clozapine (sometimes referred to as supersensitivity psychosis), (3) a psychological reaction to withdrawal, which may be mistaken for relapse or may itself precipitate relapse, (4) a genuine relapse of the underlying condition precipitated by the process of withdrawal. The implications of these effects include the possibility that much of the research on maintenance treatment is flawed and that the recurrent nature of psychiatric conditions may sometimes be iatrogenic. If withdrawal induced adverse effects could be effectively managed, the success of drug discontinuation might be much greater than usually assumed and might outweigh the disadvantages of continued treatment.

Increased writing activity in Parkinson's disease: a punding-like behavior?

We report a 32-year-old male patient with early-onset Parkinson's disease who exhibited abnormally increased writing activity. The patient displayed a disabling and pronounced increased writing activity, filling up to 10 pages or more per day in a notebook, and spending more than 12 h writing. In general, there was not much meaning in most of the writing, though there was a particular preference in tabulating the names of various sport and TV personalities. The writing activity gradually diminished following treatment with quetiapine hydrochloride, an anti-psychotic agent, at 25 mg/day. Although the pathophysiological mechanism underlying the increased writing is unclear, we believe it should be regarded as a form of punding or stereotyped behavior that has been suggested to be associated with dopaminergic therapy in Parkinson's disease.

The effect of drug abuse on body mass index in Hispanics with and without HIV infection

OBJECTIVE

There is a widely held view that the lower weight of drug abusers is attributable to diet. However, many studies on the dietary intake of drug abusers have failed to find energy insufficiency, while non-dietary factors have rarely been examined. The purpose of this study was to examine non-dietary factors that could affect the weight of drug abusers with and without HIV infection.

DESIGN

Participants were recruited into one of three groups: HIV-positive drug abusers (n=85), HIV-negative drug abusers (n=102) and HIV-positive persons who do not use drugs ('non-drug abusers', n=98). Non-dietary factors influencing weight included infection with HIV and/or hepatitis, malabsorption, resting energy expenditure and physical activity.

SETTING

The baseline data from a prospective cohort study of the role of drug abuse in HIV/AIDS weight loss conducted in Boston, USA.

SUBJECTS

The first 286 participants to enroll in the study.

RESULTS

HIV-positive drug abusers had a body mass index (BMI) that was significantly lower than that of HIV-positive non-drug abusers. The differences in weight were principally differences in fat. In the men, cocaine abuse, either alone or mixed with opiates, was associated with lower BMI, while strict opiate abuse was not. Infection with HIV or hepatitis, intestinal malabsorption, resting energy expenditure and physical activity, as measured in this study, did not explain the observed differences in weight and BMI.

CONCLUSIONS

Drug abuse, and especially cocaine abuse, was associated with lower weight in men. However, infection with HIV and/or hepatitis, malabsorption and resting energy expenditure do not explain these findings.

Psychostimulant-induced behavior as an animal model of obsessive-compulsive disorder: an ethological approach to the form of compulsive rituals

Rats treated chronically with the D2/D3 dopamine receptor agonist quinpirole show a pattern of behavior that meets a set of ethologically derived criteria of compulsive behavior in obsessive-compulsive disorder (OCD). Moreover, in both quinpirole-treated rats and OCD patients, the structure of compulsive rituals appear similar in being composed of relatively few motor acts that are organized in a flexible yet recurrent manner. In addition, the development of compulsive behavior in quinpirole-treated rats is attenuated by the OCD pharmacotherapeutic drug clomipramine. These similarities support the validity of quinpirole-treated rats as a psychostimulant-induced animal model of OCD. Considering that the induction of compulsive behavior in the rat model involves chronic hyperstimulation of dopamine receptors, this raises the possibility that dopaminergic mechanisms may play a role in OCD, at least in some subtypes of this disorder.

Punding in Parkinson's disease: its relation to the dopamine dysregulation syndrome

Punding is a term that was coined originally to describe complex prolonged, purposeless, and stereotyped behaviour in chronic amphetamine users. A structured interview of 50 patients with higher dopamine replacement therapy requirements (>800 levodopa equivalent units/day) from 123 unselected patients with Parkinson's disease (PD) from a PD clinic identified 17 (14%) patients with punding. Punding was acknowledged as disruptive and unproductive by the patients themselves, but forcible attempts by family to interrupt the behaviour led to irritability and dysphoria. Punding was associated with very high doses of dopamine replacement therapy often related to a pattern of chronic inappropriate overuse of dopaminergic medication. We believe that this is an underreported, socially disabling phenomenon that is commonly associated with the syndrome of dopamine dysregulation and is phenomenologically distinct from both obsessive-compulsive disorder and mania.

Stereotyped behaviors or punding after quetiapine administration in Parkinson's disease

Quetiapine has been suggested to be useful for the treatment of psychosis in patients with Parkinson's disease without prominent deterioration of motor functions. We present two patients with Parkinson's disease in whom administration of quetiapine for drug-induced psychosis caused characteristic stereotyped behaviors or punding. Since stereotyped behaviors are usually associated with excessive dopaminergic activity, it is clinically important to note that stereotyped behaviors or punding may be induced by an atypical antipsychotic drug for the treatment of psychosis in patients with Parkinson's disease.

Compulsive use of dopamine replacement therapy in Parkinson's disease: reward systems gone awry?

Dopamine replacement therapy (DRT) is the most effective treatment for Parkinson's disease (PD); it provides substantial benefit for most patients, extends independence, and increases survival. A few patients with PD, however, take increasing quantities of medication far beyond those required to treat their motor disabilities. These patients demand rapid drug escalation and continue to request more DRT despite the emergence of increasingly severe drug-induced motor complications and harmful behavioural consequences. In this article we detail the features of compulsive DRT-seeking and intake in PD, in relation to theories of compulsive drug use.

Effects of cocaine and putative atypical antipsychotics on rat social behavior: an ethopharmacological study

The effects of cocaine, amperozide, clozapine, olanzapine and cocaine/atypical antipsychotic combinations on aggression, affiliation and defensive behaviors was examined. Acute cocaine (30.0 mg/kg) decreased basal aggression and affiliation yet increased basal defense. Amperozide (1.0, 3.0 and 5.0 mg/kg) decreased basal aggression, affiliation and defense had no effect on the cocaine-induced decrease in affiliation, and accentuated the cocaine-induced decrease in aggression. Near basal levels of defense were observed for animals treated with either amperozide, clozapine (3.0 and 10.0 mg/kg but not 30.0 mg/kg) or olanzapine followed by cocaine. Clozapine (3.0, 10.0 and 30.0 mg/kg) decreased basal aggression and affiliation. Clozapine (30.0 mg/kg but not 3.0 or 10.0 mg/kg) decreased basal defense. Clozapine attenuated the cocaine-induced decrease in aggression. Although 3.0 and 10.0 mg/kg clozapine attenuated the cocaine-induced decrease in affiliation, 30.0 mg/kg clozapine accentuated this cocaine-induced effect. Olanzapine (1.0, 3.0 and 10.0 mg/kg) decreased basal aggression, affiliation and defense. Olanzapine had no effect on the cocaine-induced decrease in aggression. Olanzapine (3.0 mg/kg but not 1.0 or 10.0 mg/kg) attenuated the cocaine-induced decrease in affiliation. Thus, acute cocaine administration had an antiaggressive effect, suppressed affiliative behavior and enhanced defensive behavior. Amperozide, clozapine and olanzapine have anticonflict and anxiolytic effects, as well as potent and specific antiaggressive effects.

Cocaine-induced activation of striatal neurons during focused stereotypy in rats

As psychomotor stimulants, both amphetamine and cocaine elicit episodes of repetitive motor activation (focused stereotypy) known to involve the mesostriatal dopamine system. During amphetamine-induced focused stereotypy, motor-related neurons in the striatum respond with either an excitation or inhibition, depending on dose and behavioral pattern, whereas nonmotor-related units are inhibited. To assess striatal activity during the focused stereotypy induced by cocaine, both types of striatal units were recorded in ambulant rats. Either 20 or 40 mg/kg cocaine caused highly focused sniffing and head bobbing, which occurred in conjunction with activation of both motor- and nonmotor-related neurons. The activation of motor-related units was evident even when firing rate was compared during periods of matched pre- and post-drug behavior, arguing against movement as the sole basis for the drug-induced neuronal excitation. Subsequent administration of haloperidol (1.0 mg/kg) reversed but did not completely block the neuronal activation, while the behavioral response shifted away from focused stereotypy toward an increase in ambulation. Thus, the level of activation of both motor- and nonmotor-related striatal neurons may play a critical role in the behavioral response pattern induced by cocaine.

Methamphetamine plus scopolamine potentiates behavioral sensitization and conditioning

The effects of repeated methamphetamine (4.0 mg/kg) plus scopolamine (0.5 mg/kg) treatment on behavioral sensitization and drug conditioning in rats were compared with the effects of repeated methamphetamine treatment. Behavioral sensitization induced by repeated methamphetamine plus scopolamine treatment was more vigorous than that induced by repeated methamphetamine treatment. Repeated methamphetamine plus scopolamine treatment produced sensitized responses, not only to methamphetamine plus scopolamine and methamphetamine but also, to a lesser extent, to scopolamine. Methamphetamine plus scopolamine-sensitized rats but not methamphetamine-sensitized rats exhibited conditioned responses to a low-frequency tone (300 Hz, 100 dB) associated with the drug state, suggesting that robust methamphetamine plus scopolamine-induced behavioral sensitization may lead to enhanced conditioning. It is plausible that robust behavioral sensitization might operate via a reciprocal balance between the dopaminergic and cholinergic systems in favor of dopaminergic dominance. Conditioning to the drug-associated tone may be mediated via a reciprocal balance between the two transmitter systems.

Electrical sensitization of the meso-limbic dopaminergic system in rats: a pathogenetic model for schizophrenia

To study whether it was possible to modify mesolimbic dopaminergic activity by intermittent electrical stimulations (IES), 44 rats were either electrically stimulated or sham-stimulated in the ventral tegmental area (VTA) once daily for 70 days. This was done through chronically implanted intracranial electrodes. The intensity of electrical stimulation was determined by the lowest current that elicited a definite motor response. Stimulated rats demonstrated a significantly potentiated behavioral response after 70 stimulations. Seven months after IES rats still demonstrated an increased sensitivity to electrical stimulations in the VTA. A new stimulation period only resulted in a modest additional fall in threshold values. There was a highly significant difference between the current needed to provoke a given response in sensitized rats and in sham-stimulated rats. The behavioral response to stimulation was suppressed both by the dopamine (DA) D2 receptor antagonists haloperidol and raclopride and by the DA D1 receptor antagonist SCH 23390. Furthermore, stimulated rats showed an enhanced response to stimulation with amphetamine and to a lesser extent with apomorphine. Between stimulation periods sensitized animals demonstrated a reduced social interaction. In conclusion intermittent electrical stimulations of the VTA resulted in a syndrome characterized by a hypersensitive response to electrical and pharmacological DA provocation combined with abnormal social interaction. This animal model has points of resemblance with recent interpretations of the DA hypothesis for schizophrenia.

Treatment of schizophrenia: a clinical and preclinical evaluation of neuroleptic drugs

Forty years after the first clinical report on the effectiveness of chlorpromazine in psychiatric patients, neuroleptic drugs are still the most widely used drugs in the treatment of schizophrenia. Indeed, there are no other drugs which have proven to be as effective in the treatment of this severe psychiatric disorder. Yet, there are still many unresolved problems relating to neuroleptic drugs. The present review gives a comprehensive overview of our knowledge (and our lack of knowledge) with respect to the clinical and preclinical effects of neuroleptic drugs and tries to integrate this knowledge in order to identify the neuronal mechanisms underlying the therapeutic and side effects of neuroleptic drugs.

Anxiogenic effect of phenylethylamine and amphetamine in the elevated plus-maze in mice and its attenuation by ethanol

In previous experiments beta-phenylethylamine (PEA), like the standard anxiogens caffeine, pentylenetetrazole, and yohimbine, has exhibited an anxiogenic effect in the two animal models of anxiety: the social interaction test and the conflict situation test. In the present study, PEA acts as an anxiogen in an elevated plus-maze, diminishing (compared to controls) the ratio of entries into open arms over the total number of entries and shortening the time spent in the open arms. DL-Amphetamine sulfate (AMPH) also had a similar action. These data support the previous suggestion that PEA may belong to the group of endogenous anxiety-inducing compounds. Pretreatment with ethanol prevented the effects of both PEA and AMPH.

Beta-phenylethylamine (PEA): an endogenous anxiogen? Three series of experimental data

Like the anxiogenic drugs caffeine, pentylenetetrazole, and yohimbine, the endogenous neuroactive monoamine beta-phenylethylamine (PEA) is effective in three tests for anxiogens in mice. In a social interaction test it reduced both the number and duration of contacts. In a conflict situation test (a dark-light chamber) it reduced the number of transitions between dark and light compartments. Diazepam, a standard anxiolytic, prevented both effects of PEA. Intracerebroventricular administration of PEA induced generalized clonic seizures which were antagonized by various anxiolytics but not by the tested doses of butyrophenone neuroleptics and standard anticonvulsants effective in other tests for convulsants.

Freebase cocaine and memory

Despite the seriousness of acute medical and psychological consequences of cocaine abuse, little knowledge exists about the chronic effects of the drug. Investigation of a sample of abstinent freebase (crack) abusers in the Bahamas provides the first research evidence that prolonged cocaine abuse may result in persistent short-term memory disturbances.

d-Amphetamine-induced "floating limb" syndrome in young rhesus monkeys

Acute d-amphetamine administration to young rhesus monkeys (N = 10) caused a motor syndrome of hypoactivity and chorea-like postures and motor movements which we have termed "floating limb". Frequently after subcutaneous injections of 0.3 or 0.6 mg/kg d-amphetamine, an affected monkey raised one or both legs or arms and held the limb(s) motionless in the air. Affected limbs were usually returned to a normal position if they appeared to enter the animal's visual field. In other cases, the monkey assumed bizarre and contorted postures which were held for prolonged periods. Such postures were often accompanied by gentle repetitive brushing of the ears and facial hair with extremities of the affected limbs. Quantification of the frequency of these movements showed that they occurred regularly for 90-150 min after d-amphetamine. Hydroxyamphetamine, a peripherally-acting amphetamine analog, did not induce floating limb, indicating that the behavior was probably mediated by central actions of d-amphetamine. A similar disorder has been reported occasionally in other studies with monkeys and cats. It may be related to the chorea that is seen in humans after the use of amphetamine and other stimulants. d-Amphetamine treatment in young monkeys may provide a viable model of human choreoathetoid disorders induced by disease or drug use.

Pathology, phenomenology and the dopamine hypothesis of schizophrenia

The dopamine hypothesis of schizophrenia implies that positive schizophrenic symptoms should be understandable by reference to brain structures receiving a dopamine innervation, or in terms of the functional role of dopamine itself. The basal ganglia, ventral striatum, septo-hippocampal system, and prefrontal cortex, sites of mesotelencephalic dopamine innervation, are examined and it is argued that their dysfunction could form the basis of particular schizophrenic symptom classes. The postulated involvement of dopamine in reinforcement processes might further assist such interpretations. This type of analysis can be extended to other categories of schizophrenic psychopathology.

Multiple amphetamine injections reduce the release of ascorbic acid in the neostriatum of the rat

Voltammetric signals were recorded bilaterally with unmodified or electrochemically-modified carbon-fiber electrodes in the neostriatum of rats that sustained a unilateral depletion of dopamine by pretreatment with 6-hydroxydopamine. In both hemispheres, single daily injections of D-amphetamine (5.0 mg/kg or steadily increasing doses beginning with 6.0 mg/kg) for 6 consecutive days significantly reduced the rise in oxidation current produced by a challenge injection of 2.5 mg/kg D-amphetamine compared to the response obtained from saline-treated controls. Voltammetric scans indicated that the oxidized substance shared the electrochemical characteristics of ascorbic acid. It appears, therefore, that multiple amphetamine injections reduce the release of ascorbic acid in the neostriatum and that this effect does not depend on the integrity of dopaminergic neurons.

Critical issues in assessing the behavioral effects of amphetamine

Amphetamine induces a behavioral syndrome in mammals that includes a variety of repetitive behaviors. An integral component of this syndrome in humans is the presence of a thought disturbance not unlike that manifest in idiopathic paranoid schizophrenia. The consistent pattern of behavioral changes produced by amphetamine across species, when considered in light of the psychosis it elicits in humans, has suggested to many that these drug-induced changes in animals may provide a model of the endogenous psychosis in humans. Amphetamine-induced changes in open-field behavior in the rat have been the most widely studied in attempts to formulate a model for investigating the neurobiological mechanisms underlying amphetamine psychosis and paranoid schizophrenia in humans and for testing the therapeutic efficacy of new antipsychotic drugs. The procedures used to assess the behavioral response to amphetamine, however, typically include rating scales or automated recordings that by their very nature ignore those components of the behavioral response that may be most critical for developing a viable animal model of the naturally occurring psychosis. Further, open-field behavior is often recorded during arbitrarily selected intervals without consideration for the multiphasic nature of the entire amphetamine response. We discuss how incomplete descriptive analyses of the amphetamine behavioral response in rats has led to confusion in the literature and describe behavioral research that is paradigmatic of the work we believe is most likely to eventuate in significant progress in the field.

Central depressant action of cesium in mice

Cesium chloride (CsCl) at several dose levels (1.25-20.0 mEq/kg IP) was administered acutely to albino mice whose behavior was compared with that in corresponding saline controls. Motor activity decreased and Straub tail occurred in a dose-related manner. Signs of autonomic disturbance, diarrhea, and salivation were seen with toxic doses. Subchronic administration of CsCl (5.0 mEq/kg/day IP for 7 days) exerted a phenothiazine-like effect in mice, reducing amphetamine-induced aggregation toxicity and enhancing pentobarbital-induced hypnosis. The antinociceptive action of morphine was unaltered by identical multiple administrations of CsCl. These results indicate a specific neurosuppressant action of CsCl on mouse CNS and suggest exploration of this alkali earth metal for antipsychotic-like activity.

d-Amphetamine in squirrel monkeys of different social status: effects on social and agonistic behavior, locomotion, and stereotypies

The influences of social status on amphetamine-induced behavioral effects in squirrel monkeys were investigated. Social status was determined by constructing a sociogram. d-Amphetamine (0.3--1.0 mg/kg orally, 0.3 and 0.6 mg/kg IM) increased stereotyped head movements and reduced the time spent in the sitting posture in all monkeys (N = 25) regardless of sex, age, or social status. The high levels of locomotor activity in dominant and juvenile monkeys were decreased at higher amphetamine doses (0.6 mg/kg IM, 0.6 and 1.0 mg/kg orally), whereas the same doses increased locomotion in otherwise less active subdominant and submissive animals. Low doses of amphetamine (0.1, 0.3 mg/kg) decreased the incidence of agonistic behavior initiated by dominant monkeys, and higher doses (0.6, 1.0 mg/kg) caused these monkeys to change from predominant initiators of agonistic behavior into recipients. At 2 h after amphetamine administration (0.3 mg/kg IM), the high levels of locomotor behavior had returned to baseline, the social isolation began to disappear, and the disrupted agonistic behavior of dominant monkeys returned to control levels, yet the stereotyped head movements continued to occur with high frequency. In half of the monkeys, amphetamine produced a large increase in distress-like vocalizations. Amphetamine-mediated motor stereotypies may be mediated by mechanisms different than those responsible for agonistic behavior. The selective changes in agonistic behavior by dominant monkeys when challenged with amphetamine may reflect a status-related functional alteration of catecholaminergic processes upon which the drug acts.