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Biomedical subjects

Guy Chouinard

Publications and source records attributed to Guy Chouinard.

At least 19 recordsLinked to original sources
PubMed2006

Persistent tardive rebound panic disorder, rebound anxiety and insomnia following paroxetine withdrawal: a review of rebound-withdrawal phenomena.

OBJECTIVE: To describe tardive rebound anxiety phenomena (panic, anxiety and insomnia) following abrupt paroxetine discontinuation. METHOD: Case report, with comprehensive literature review on rebound and withdrawal phenomena associated with psychotropic medications. RESULTS: Three different discontinuation syndromes with psychotropics are described: (1) new-onset CNS-depressant type withdrawal symptoms (minor and major); (2) rebound syndromes; and (3) supersensitivity symptoms. Abrupt paroxetine discontinuation has been well described and fits the first category. Tardive rebound panic disorder-phenomena with paroxetine has some features of the supersensitivity category. CONCLUSION: Chronic paroxetine treatment may lead to 5-HT2-receptor down regulation, with desensitization of 5-HT1A and 5-HT2 receptors, which may contribute to tardive rebound symptoms upon abrupt withdrawal. Early reports suggest that genetic factors may also contribute to withdrawal symptoms in susceptible individuals. Cholinergic rebound may also occur and could explain tardive insomnia and anxiety in paroxetine withdrawal.

Aged↗
PubMed2006

The search for new off-label indications for antidepressant, antianxiety, antipsychotic and anticonvulsant drugs.

Most drugs are prescribed for several illnesses, but it took several years for psychotropic drugs to have multiple clinical indications. Our search for serotonergic drugs in affective illnesses and related disorders led to new off-label indications for fluoxetine, sertraline, tryptophan, clonazepam, alprazolam, tomoxetine, buproprion, duloxetine, risperidone and gabapentin. Various clinical trial designs were used for these proof-of-concept studies. Novel therapeutic uses of benzodiazepines, such as in panic disorder and mania, were found with the introduction of 2 high-potency benzodiazepines, clonazepam and alprazolam, which were thought to have serotonergic properties. Our initial clinical trials of fluoxetine and sertraline led to their approved indications in the treatment of obsessive-compulsive disorder, and our trials of gabapentin led to new indications in anxiety disorders (generalized anxiety, panic attack and social phobia) and sleep disorders (insomnia).

Animals↗
PubMed2006

Interrelations between psychiatric symptoms and drug-induced movement disorder.

After 30 years of clinical research into drug-induced movement disorder (DIMD), we are still facing unresolved issues regarding the interrelations between psychiatric symptoms and DIMD. Recently, I proposed a new classification of DIMD that includes abnormal movements previously labelled extrapyramidal symptoms. DIMD caused by psychotropic drugs is still confused with psychiatric symptoms treated by the same drugs. The results from 2 international multicentre trials, the InterSePT and the Ris-Consta Studies, conducted in the era of both typical and atypical antipsychotic agents, which included over 3,000 patients with schizophrenia and schizoaffective disorder worldwide, still showed a high, but decreasing, incidence of pretreatment DIMD, which varied from 57.5% (1998-1999) to 47.4% (1999-2000), and a decreasing incidence of tardive dyskinesia, which varied from 12% (1998-1999) to 10.2% (1999-2000), reflecting the greater use of atypical antipsychotic drugs. Furthermore, in both studies, psychiatric symptoms as measured by the Positive and Negative Symptom Scale (PANSS) were significantly correlated with DIMD and DIMD subtypes, thus suggesting the need for additional measurement instruments in schizophrenia and related psychoses.

Depressive Disorder↗
PubMed2005

Abnormal Involuntary Movement Scale (AIMS) and Extrapyramidal Symptom Rating Scale (ESRS): cross-scale comparison in assessing tardive dyskinesia.

Assessing tardive dyskinesia (TD) has been complicated by the use of different research criteria and rating scales. We studied concordance between two commonly used scales, the Abnormal Involuntary Movement Scale (AIMS) and Extrapyramidal Symptom Rating Scale (ESRS), to study interscale concordance and criteria to define TD. Patients with schizophrenia or schizoaffective disorder (N = 374) were rated at baseline with both scales. Linear and logistic regression models explored relationships between scale ratings and mapped scores for corresponding items. TD was defined as at least mild in > or = 2 anatomical areas, or moderate or greater symptoms in > or = 1 area at baseline. Logistic regression was used to find simplified criteria for predicting AIMS-defined TD by ESRS scores. There was a strong association on corresponding item ratings. "Mild" was defined as AIMS score of 2 and ESRS 2 or 3, and "moderate or greater" as AIMS score > or = 3 and ESRS > or = 4. Using these criteria, there was 96.0% (359/374) agreement between AIMS- and ESRS-defined TD cases. The ESRS Clinical Global Impressions of severity of dyskinesia (CGI-SD) best predicted AIMS-defined TD. An ESRS CGI-SD > or = 4 (95% CI: 3.61, 4.76) was associated with > or = 95% probability of AIMS-defined TD. High concordance between the scales for dyskinesia scores was found. Findings suggest that the ESRS CGI-SD score can serve as a simplified criterion for identifying AIMS-defined TD, and may be a useful tool for future research-based TD analyses, when occurring in the context of a full movement disorder assessment.

Adolescent↗
PubMed2005

Manual for the Extrapyramidal Symptom Rating Scale (ESRS).

The Extrapyramidal Symptom Rating Scale (ESRS) was developed to assess four types of drug-induced movement disorders (DIMD): Parkinsonism, akathisia, dystonia, and tardive dyskinesia (TD). Comprehensive ESRS definitions and basic instructions are given. Factor analysis provided six ESRS factors: 1) hypokinetic Parkinsonism; 2) orofacial dyskinesia; 3) trunk/limb dyskinesia; 4) akathisia; 5) tremor; and 6) tardive dystonia. Two pivotal studies found high inter-rater reliability correlations in both antipsychotic-induced movement disorders and idiopathic Parkinson disease. For inter-rater reliability and certification of raters, >or=80% of item ratings of the complete scale should be +/-1 point of expert ratings and >or=70% of ratings on individual items of each ESRS subscale should be +/-1 point of expert ratings. During a cross-scale comparison, AIMS and ESRS were found to have a 96% (359/374) agreement between TD-defined cases by DSM-IV TD criteria. Two recent international studies using the ESRS included over 3000 patients worldwide and showed an incidence of TD ranging from 10.2% (2000) to 12% (1998). ESRS specificity was investigated through two different approaches, path analyses and ANCOVA PANSS factors changes, which found that ESRS measurement of drug-induced EPS is valid and discriminative from psychiatric symptoms.

Basal Ganglia Diseases↗
PubMed2005

Gabapentin in the treatment of antipsychotic-induced akathisia in schizophrenia.

Antipsychotic-induced akathisia is characterized by subjective and objective motor restlessness, which is observed as a common extrapyramidal side-effect of antipsychotic agents. A patient is described who had antipsychotic-induced akathisia unresponsive to conventional therapy, and who began gabapentin therapy for insomnia. Significant improvement in his akathisia occurred when the gabapentin dose was increased, and his other treatment for akathisia was decreased and discontinued. Gabapentin may be effective by mechanisms similar to its action in restless legs syndrome and Parkinsonism, and/or via the GABA neurotransmitter system.

Adult↗
PubMed2005

Tardive dyskinesia in the era of typical and atypical antipsychotics. Part 1: pathophysiology and mechanisms of induction.

OBJECTIVE: Tardive dyskinesia (TD) is the principal adverse effect of long-term treatment with conventional antipsychotic agents. Several mechanisms may exist for this phenomenon. Mechanisms for the lower incidence of TD with atypical antipsychotics also remain to be fully understood. We undertook to explore and better understand these mechanisms. METHODS: We conducted a comprehensive review of TD pathophysiology literature from January 1, 1965, to January 31, 2004, using the terms tardive dyskinesia, neuroleptics, antipsychotics, pathophysiology, and mechanisms. Additional articles were obtained by searching the bibliographies of relevant references. Articles were considered if they contributed to the current understanding of the pathophysiology of TD. RESULTS: Current TD vulnerability models include genetic vulnerability, disease-related vulnerability, and decreased functional reserve. Mechanisms of TD induction include prolonged blockade of postsynaptic dopamine receptors, postsynaptic dopamine hypersensitivity, damage to striatal GABA interneurons, and damage of striatal cholinergic interneurons. Atypical antipsychotics may cause less TD because they have less impact on the basal ganglia and are less likely to cause postsynaptic dopamine hypersensitivity. CONCLUSION: Although the ultimate model for TD is not yet understood, it is plausible that several of these vulnerabilities and mechanisms act together to produce TD. The lower incidence of TD with atypical antipsychotics has helped to elucidate the,mechanisms of TD.

Antipsychotic Agents↗
PubMed2005

Tardive dyskinesia in the era of typical and atypical antipsychotics. Part 2: Incidence and management strategies in patients with schizophrenia.

OBJECTIVE: Tardive dyskinesia (TD), the principal adverse effect of long-term conventional antipsychotic treatment, can be debilitating and, in many cases, persistent. We sought to explore the incidence and management of TD in the era of atypical antipsychotics because it remains an important iatrogenic adverse effect. METHODS: We conducted a review of TD incidence and management literature from January 1, 1965, to January 31, 2004, using the terms tardive dyskinesia, management, therapy, neuroleptics, antipsychotics, clozapine, olanzapine, risperidone, quetiapine, ziprasidone, and aripiprazole. Additional articles were obtained by searching the bibliographies of relevant references. We considered articles that contributed to the current understanding of both the incidence of TD with atypical antipsychotics and management strategies for TD. RESULTS: The incidence of TD is significantly lower with atypical, compared with typical, antipsychotics, but cases of de novo TD have been identified. Evidence suggests that atypical antipsychotic therapy ameliorates long-standing TD. This paper outlines management strategies for TD in patients with schizophrenia. CONCLUSION: The literature supports the recommendation that atypical antipsychotics should be the first antipsychotics used in patients who have experienced TD as a result of treatment with conventional antipsychotic agents. The other management strategies discussed may prove useful in certain patients.

Antipsychotic Agents↗
PubMed2004

A review of compliance, depot intramuscular antipsychotics and the new long-acting injectable atypical antipsychotic risperidone in schizophrenia.

BACKGROUND: Several oral atypical antipsychotics are available for schizophrenia management. Besides positive and negative symptom control, they may improve cognition. Due to their limited availability as oral agents only, benefits are limited by noncompliance. METHODS: Using Medline and PsycINFO databases, literature was reviewed to address: (1) factors underlying medication noncompliance; (2) available evidence on efficacy of depot intramuscular (IM) typical antipsychotics; and (3) current knowledge of long-acting atypicals. RESULTS: Noncompliance remains high due to illness-, treatment-, and clinician-related factors. Compared to oral typicals, atypicals may improve compliance, even though noncompliance remains high. Depot IM typicals are efficacious (reduced relapses and rehospitalizations), but extrapyramidal symptoms are problematic. Available data on long-acting atypical risperidone suggest that it is safe and efficacious. CONCLUSION: Development of long-acting injectable atypical agents is warranted since noncompliance remains high. Future long-acting IM atypical trials should include outpatient functioning, and preferably be of longer duration to address cost-effectiveness.

Antipsychotic Agents↗
PubMed2004

The international suicide prevention trial (interSePT): rationale and design of a trial comparing the relative ability of clozapine and olanzapine to reduce suicidal behavior in schizophrenia and schizoaffective patients.

Suicidal behavior in patients with psychotic disorders represents a seriously undertreated life-threatening condition. The International Suicide Prevention Trial (InterSePT) is the first large-scale, prospective study designed to evaluate the potential of antipsychotic medications to reduce suicidal behaviors in patients with schizophrenia or schizoaffective disorder who are known to be at high risk for suicide. The unique challenges to study design and the solutions identified for the InterSePT study are described. These challenges included defining suicidal behavior in patients with psychosis, endpoint selection, determination of analytic strategy, and development of scales to assess suicidal behavior. Given the life-threatening nature of suicidal behavior, ethical considerations required that the design minimize suicide attempts and deaths. While the study focused primarily on treatment of suicide, opportunities were used to collect data in related areas of interest, including suicide risk factors, other efficacy measures (e.g., Positive and Negative Syndrome Scale, Covi Anxiety Scale, Calgary Depression Scale), adverse events, pharmacoeconomics, and pharmacogenetics. Because of the complexity of the design issues, a steering committee, suicide monitoring board, and publication committee were established to assist with their management.

Adolescent↗
PubMed2004

Diabetes, tardive dyskinesia, parkinsonism, and akathisia in schizophrenia: a retrospective study applying 1998 diabetes health care guidelines to antipsychotic use.

BACKGROUND: This study examines the links among diabetes, tardive dyskinesia (TD), and other extrapyramidal symptoms (EPS) in schizophrenia outpatients treated with typical and atypical antipsychotics. OBJECTIVES: Using a retrospective chart review, we compared 30 schizophrenia patients with diabetes mellitus (DM) with 30 schizophrenia patients, matched for age and sex, with no DM. We compared prevalence and severity of parkinsonism, akathisia, TD, dystonia, and antipsychotic type (that is, typical vs atypical). RESULTS: We found no statistically significant differences between the DM group and the non-DM group prevalence and severity of EPS, including TD. CONCLUSION: We did not find DM and TD association to be significant in the era of atypical antipsychotics, possibly because of their antidyskinetic effect.

Antipsychotic Agents↗
PubMed2004

Issues in the clinical use of benzodiazepines: potency, withdrawal, and rebound.

Low and medium potency benzodiazepines were initially introduced for the treatment of insomnia and anxiety. Their therapeutic actions as anxiolytics, sedative hypnotics, anticonvulsants, and muscle relaxants (with their low toxicity) have led to their use as first-line treatments, and they have become one of the most prescribed classes of drugs. Novel therapeutic uses of benzodiazepines were discovered with the introduction of the high-potency benzodiazepines (e.g., alprazolam, clonazepam, and lorazepam). They were found to be effective in treating panic disorder and panic attacks with or without agoraphobia, as add-on therapy to selective serotonin reuptake inhibitors in the treatment of obsessive-compulsive disorder and panic disorders, and as adjunctive therapy in treating patients with acute mania or acute agitation. High-potency benzodiazepines have replaced low and medium potency benzodiazepines in all benzodiazepine clinical indications due to their greater therapeutic effects and rapid onset of action. Differences in distribution, elimination half-life, and rate of absorption are important considerations when choosing a high-potency benzodiazepine. Typically, a benzodiazepine with long distribution and elimination half-lives is preferred. A maximum dose of 2 mg/day of any of the high-potency benzodiazepines when given for more than 1 week is recommended. Although as a class benzodiazepines act rapidly and are well tolerated, their use presents clinical issues such as dependence, rebound anxiety, memory impairment, and discontinuation syndrome.

Amnesia↗