Essential psychopharmacology最新文献

Psychiatric comorbidity is all too common. An important example is the high comorbidity frequency of depressive and anxiety disorders, 25%-50%, much higher than the 5% or less expected by chance. Possible reasons for this comorbidity include definitional, environmental, and biological factors. Few previous studies have assessed, with proper methodology, potential biological changes associated with this co-occurrence. We assessed both hypothalamic-pituitary-adrenocortical axis (HPA) responses to the Trier Social Stress Test and growth hormone (GH) responses to clonidine, a centrally active alpha-2 adrenoreceptor agonist, in 15 persons with major depression without anxiety, 15 with an anxiety disorder without depression, 18 comorbid for anxiety and depression, and 48 individually matched control subjects. Individuals with depression only were normal on both tests, while those with anxiety only had normal HPA responses but blunted GH responses. Comorbid individuals showed elevated HPA responses and only those comorbid persons with anxiety symptoms predominant also showed blunted GH responses. Controls and anxiety-only subjects showed significant correlations between the results of the two tests. This association was disrupted by the presence of depression with or without comorbidity. Comorbidity is fundamental to understanding the pathophysiologies of depression and anxiety.

Antipsychotic medications, specifically the atypical agents, serve as first-line treatment options for patients with psychotic disorders, including individuals with schizophrenia or schizoaffective disorder. Atypical antipsychotics are also often prescribed off-label as either the primary treatment or as an adjunctive treatment for individuals with other disorders, including mood disorders without psychosis, behavioral disorders, and insomnia. Despite the generally superior side-effect profiles of atypical antipsychotics compared with typical antipsychotic agents, the atypicals have been associated with a number of serious side effects, including metabolic disorders, cardiovascular disorders, seizures, hyperprolactinemia, and movement disorders. This article offers a stepwise approach to the management of antipsychotic side effects: Abstinence, Anticipation, Reduction, and Treatment (AART). The steps in AART are hierarchical, but often overlap in the areas of risk prevention and minimization. The authors discuss issues relevant to each level of intervention and provide suggestions for integrating the AART approach into a comprehensive treatment plan. By incorporating this stepwise approach into their clinical decision-making process, prescribers may be able to optimize the risk:benefit ratio associated with the prescription of atypical antipsychotics.

Biological interactions are stereoselective; thus the interactions of drugs with corresponding biological targets must also be stereoselective. However, many drugs used today are racemic mixtures. For example, approximately 25% or 1 in 4 marketed drugs are mixtures of agents (racemates) rather than single chemical entities (enantiomers). One of these enantiomers can be inactive or even counterproductive to the therapeutic use of the drug: either by reducing the efficacy of the active enantiomer or by causing unnecessary tolerability problems or even toxicity through differential pharmacodynamics. The presence of a therapeutically inactive or counterproductive enantiomer can also complicate the pharmacokinetics of the active enantiomer and the interpretation of the therapeutic drug monitoring (e.g., plasma levels) if the assay is not capable of separately quantitating the two enantiomers. This article reviews the history of stereoisomers and the relevant pharmacological principles, then discusses recent changes in rules governing drug approval and the potential advantages to the patient and the manufacturer of developing single enantiomers.

Even today, pharmacotherapy for mood disorders is based almost entirely on the observation in the 1950s and 1960s that agents that enhance monoamine transmitter activity are effective antidepressants. Preclinical studies have shown that long-term administration of nearly all effective antidepressants increases the efficiency of postsynaptic serotonin transmission; many also modify central noradrenergic activity. For the majority of antidepressants, these changes are the result of their ability to block serotonin and/or norepinephrine activity at their "presynaptic uptake sites" (i.e., at the serotonin transporter [SERT] or the norepinephrine transporter [NET]). Drugs that are highly selective for one transporter over another have been demonstrated to be effective and tolerable, whereas agents that act on multiple transporters may not necessarily achieve better efficacy and may result in additional adverse events. The rationale for the use of drugs that affect multiple transports is based on the suggestion that antidepressants that block both the SERT and the NET may provide better efficacy. This can only be determined through empirical studies.

Cytokines are peripherally and centrally produced proteins that regulate immune and immunological responses. They also have neurochemical, neuroendocrine and behavioural effects similar to those seen in patients with depression. A review of the literature reveals several cytokines, including IL-1beta, IL-2, IL-6 and IFN, have been shown to be elevated in plasma of working-age adults with depression and dysthymia. A more detailed review of the literature also reveals similar associations between cytokines and late-life depression, with IL-1beta, IL-6 and TNF-alpha all being reported to be elevated in both depression and dysthymia. It has been hypothesized that cytokines provide the link between depression, neurochemical changes and the altered HPA axis that are known to occur in this disease, and evidence is presented that supports this view. However, the evidence that antidepressants may have effects on cytokines is conflicting. Increased cytokine levels may also serve as an explanation for the increased risk for vascular disease that has been associated with depression, and a possible mechanism for this is discussed.

Conduct disorder (CD) is one of the most common psychiatric disorders in childhood and adolescence. It is characterized by a variety of chronic antisocial behaviors, a repetitive and persistent pattern of behavior that violates the basic rights of others, major age-appropriate societal norms, or both. Aggressive behavior, lying, stealing, fire-setting, and running away from home and school are the most frequent manifestations of CD and are often accompanied by hyperactivity, impulsive behavior, explosiveness, cognitive and learning problems, and poor social skills. The rate of comorbidity is high, with attention-deficit hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD) being the most common; comorbid anxiety and depressive disorders are also seen, especially in adolescents. The diagnostic process should include the use of structured interviews, and scores from reliable and valid rating scales that cover all psychiatric disorders must be considered in the differential diagnosis, because CD alone is an extreme rarity and multiple disorders are almost always the rule rather than exception. Treatment should include parenting skills training combined with training of the child to improve his or her relationships with peers, academic performance, and compliance with legitimate demands of authority figures. The appropriate use of medications and integration of patient/parent education and support, as well as individual, group, family, residential, and inpatient treatment may be beneficial for patients with CD and ADHD. The article describes a number of psychopharmacological agents that are used in patients with CD with ADHD and other comorbid disorders. Drugs that may be useful include psychostimulants; atomoxetine (Strattera); antidepressants (imipramine [Tofranil], desipramine [Norpramin]); Selective Serotonin Reuptake Inhibitors (SSRIs); atypical antipsychotics such as risperidone (Risperdal); or mood regulators including lithium (Eskalith).

The first atypical antipsychotic, clozapine (Clozaril), dramatically improved the outcome of treatment of patients with schizophrenia in two ways. First, it reduced psychotic symptoms without eliciting significant neurological side effects. Second, it was effective in approximately 30% of individuals who were previously refractory to treatment. Efforts to develop similar drugs have been partially successful in that newer antipsychotics are also less likely to produce neurological side effects. However, it has not yet been established that the newest antipsychotics are more effective than conventional agents in individuals who are refractory to treatment. In the first part of this review, the results of studies that evaluated the new antipsychotics and provided an outcome measure of response rate (regardless of how this index was defined) are summarized. Even with this broad criterion, the evidence suggests that the newer antipsychotics do not share the clinical advantages of clozapine. To explore the possible mechanisms for the clinical advantage of clozapine, evidence of antipsychotic-induced dopamine release in the brain is discussed in the second half of this article. This analysis indicates that acute clozapine administration induces the release of more dopamine in the cortex than in the striatum or limbic system. With conventional antipsychotics, this relationship is reversed. The newest antipsychotics do not show a preference among these sites. Moreover, after long-term treatment, tolerance develops to haloperidol, but not to clozapine, with regard to the amount of dopamine released in the brain. No data are available on the newest antipsychotics. Although more studies need to be done-especially studies of the effects of long-term administration of various conventional and atypical antipsychotics-this distinction might be relevant to the unique clinical advantage of clozapine.

In order to win FDA approval, generic drugs must demonstrate bioequivalence, namely the ability to achieve blood levels similar to those of the innovator ones on which they are based. They must have the same active ingredients, be identical in strength, dosage form, and route of administration, and be manufactured under strict FDA standards. Because basic efficacy and safety studies are not required, their cost is significantly lower. However, there can be important differences between the innovator drugs and generics, as well as among the generics themselves. More research needs to be done to establish true comparability.