The first-line treatment for psychotic disorders remains antipsychotic drugs with receptor antagonist properties at D₂-like dopamine receptors. However, long-term administration of antipsychotics can ...upregulate D₂ receptors and produce receptor supersensitivity manifested by behavioral supersensitivity to dopamine stimulation in animals, and movement disorders and supersensitivity psychosis (SP) in patients. Antipsychotic-induced SP was first described as the emergence of psychotic symptoms with tardive dyskinesia (TD) and a fall in prolactin levels following drug discontinuation. In the era of first-generation antipsychotics, 4 clinical features characterized drug-induced SP: rapid relapse after drug discontinuation/dose reduction/switch of antipsychotics, tolerance to previously observed therapeutic effects, co-occurring TD, and psychotic exacerbation by life stressors. We review 3 recent studies on the prevalence rates of SP, and the link to treatment resistance and psychotic relapse in the era of second-generation antipsychotics (risperidone, paliperidone, perospirone, and long-acting injectable risperidone, olanzapine, quetiapine, and aripiprazole). These studies show that the prevalence rates of SP remain high in schizophrenia (30%) and higher (70%) in treatment-resistant schizophrenia. We then present neurobehavioral findings on antipsychotic-induced supersensitivity to dopamine from animal studies. Next, we propose criteria for SP, which describe psychotic symptoms and co-occurring movement disorders more precisely. Detection of mild/borderline drug-induced movement disorders permits early recognition of overblockade of D₂ receptors, responsible for SP and TD. Finally, we describe 3 antipsychotic withdrawal syndromes, similar to those seen with other CNS drugs, and we propose approaches to treat, potentially prevent, or temporarily manage SP.
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, ≥
80% of item ratings of the complete scale should be ±
1 point of expert ratings and ≥
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.
Background: Benzodiazepines are not all the same concerning their risk of high-dose use. Methods: We studied benzodiazepine use from the Luxembourg national records of all insured. We calculated the ...12-year prevalence from 1995 to 2007. Benzodiazepine users were divided into 3 groups, short-term with no longer than 3-month intake, intermediate with multiple administration with at least a 1-year interruption, and continuous who never stopped. A high-dose user (HDU) was defined as a patient who received a higher dose than the yearly maximum usual therapeutic dose. Results: An average of 16.0% of the adult insured population received at least 1 benzodiazepine annually, 42.9% were older than 50, 55.9% were women, and 5.4% were HDUs. We found that 32.6% were short-term users, 49.0% intermediate and 18.4% continuous. Compared to diazepam, hypnotics had higher risks for high-dose use in at least 1 age group at first-benzodiazepine intake, the risks being greater in elderly subjects and women, the highest risks being with triazolam (adjusted odds ratio = 215.85; 95% confidence interval = 133.75-348.35) in the 69- to 105-year-old group at first-benzodiazepine intake. Anxiolytics had a low risk except for alprazolam and prazepam in the 69- to 105-year-old group at first-benzodiazepine intake, clonazepam and clobazam had the lowest risk in 18- to 43-year-olds at first-benzodiazepine intake. Alprazolam had dispensed volumes increased by threefold over the 12-year period. Conclusion: All hypnotics had higher risks for high-dose use compared to diazepam in continuous users. Two anxiolytics, clonazepam and clobazam, had the lowest risks. Hypnotics and the triazolobenzodiazepines alprazolam and triazolam were most problematic. Elderly subjects and women are at greater risks.
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.
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.
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