Psychosis Antipsychotics specific

With the introduction of chlorpromazine in 1952, there was a small revolution in psychiatry patients suffering from psychosis were able to be de-institutionalized. Chlorpromazine and other typical antipsychotics (e.g., haloperidol) demonstrate high in vitro binding affinities for the dopamine D2 receptor (D2). Specifically, their... 

The positive symptoms are the most responsive to antipsychotic medications, such as chlorpromazine or halo-peridol. Initially, these drugs were thought to be specific for schizophrenia. However, psychosis is not unique to schizophrenia, and frequently occurs in bipolar disorder and in severe major depressive disorder in which paranoid delusions and auditory hallucinations are not uncommon (see Ch. 55). Furthermore, in spite of early hopes based on the efficacy of antipsychotic drugs in treating the positive symptoms, few patients are restored to their previous level of function with the typical antipsychotic medications [2]. 

These authors also examined which medications were prescribed to patients with specific diagnoses. The majority of antidepressants were prescribed for patients with major depression, dysthymia, or bipolar disorder. Antipsychotics were prescribed frequently for conduct/oppositional disorder, psychosis, and major depression or dysthymia. In the state hospital, the proportion of nonpsychotic patients who received antipsychotic treatment depended on patients age thus, the frequency of children who were not diagnosed with a psychotic disorder but who were treated with antipsychotic medication was greater among children 12 years and younger, in contrast to children ages 13 to 18 years. 

Antipsychotics have a broad-spectrum effect, improving psychosis in schizophrenia, schizophreniform disease, mania, and organic psychosis but response to lithium suggests an affective core. Whereas almost all schizophreniform patients are presently treated with antipsychotics, it is possible that lithium may be more specific and safer in the management of at least some of these patients. 

The psychosis that least resembles dreaming is that of schizophrenia, because, like mania, it has the paranoia and accusatory auditory hallucinations (which dreaming lacks), and the emotional tone is often flat (about as far away from dream elation as we can get). Anxiety is about the only shared property, and that is not very specific. Perhaps it should come as no surprise that the typical schizophrenic psychosis is so different from that of dreaming. After all, it is the neuromodulator dopamine that has been most strongly implicated in the pathogenesis of schizophrenia, and that is the only neuromodulator that has not been implicated in dreaming. We will discuss this interesting difference in more detail when we consider how antipsychotic medication may work. 

Although the usefulness of the atypical antipsychotics is best documented for the positive symptoms of schizophrenia, numerous studies are documenting the utility of these agents for the treatment of positive symptoms associated with several other disorders (discussed in Chapter 10 see Fig. 10—2). Atypical antipsychotics have become first-line acute and maintenance treatments for positive symptoms of psychosis, not only in schizophrenia but also in the acute manic and mixed manic-depressed phases of bipolar disorder in depressive psychosis and schizoaffective disorder in psychosis associated with behavioral disturbances in cognitive disorders such as Alzheimer s disease, Parkinson s disease, and other organic psychoses and in psychotic disorders in children and adolescents (Fig. 11—52, first-line treatments). In fact, current treatment standards have evolved in many countries so that atypical antipsychotics have largely replaced conventional antipsychotics for the treatment of positive psychotic symptoms except in a few specific clinical situations. 

As researchers learned more about the neurologic changes involved in psychosis, drugs were developed to specifically treat disorders rather than simply sedate the patient. These antipsychotic drugs, or neuroleptics, as some clinicians refer to them, represent a major breakthrough in the treatment of schizophrenia and other psychotic disorders. 

Consequently, antipsychotic drugs all share a basic mechanism of action that involves dopamine receptor blockade. It is apparent, however, that they are not all equal in their ability to affect specific sub-types of dopamine receptors, and that their effectiveness and side effects are related to their affinity and preference for certain receptors. As indicated earlier, other neurotransmitters may also be involved in the pathogenesis of psychosis, and differences in specific antipsychotic medications may be related to their ability to directly or indirectly affect these other transmitters as well as block dopamine influence. Future studies will continue to clarify how current antipsychotics exert their beneficial effects and how new agents can be developed to be more selective in their effects on dopamine and other neurotransmitter pathways. 

The neuroleptic drugs are psychiatry s most notorious drug treatment. They are the principle treatment for the most severe and symbolic of psychiatric conditions, such as schizophrenia or psychosis, but they are intensely disliked by many patients who therefore often have to be forced or pressurised to take them. They are also a focus of controversy due to claims about their brain damaging effects. They have been known under many names including major tranquillisers and phenoth-iazines, but are now mostly referred to as antipsychotics a term that originated in North America. However to avoid the implications of disease specificity that this name implies I will mainly refer to them here as neuroleptics, a term that, as I explain below, better describes their characteristic actions. 

It is not clear that so-called antipsychotic drugs are superior to other types of drugs with sedative effects but different mechanisms of action. Lithium, benzodiazepines and opium have been shown to be comparable to neuroleptics in the treatment of psychotic states in some studies. The ability of the neuroleptic drugs to reduce the most characteristic symptoms of psychosis such as hallucinations, delusions and thought disorder have often been interpreted as evidence of their specifically antipsychotic or antischizophrenic action (The National Institute of Mental Health Psychopharmacology Service Center Collaborative Study... 

Cannabidiol Attentuated apomorphine-induced stereotypy in animal model of psychosis-similar to effect of other antipsychotic drugs. Animal study showed increased prolactin secretion similar to described antipsychotic effect. Based on observed effects, mechanism of action may be similar to atypical antipsychotics, though no data available on specific neurotransmitters involved. 

Psychiatrists prescribe antipsychotics to treat mental illnesses that cause patients to experience marked breaks with reality (psychosis). The most common of such disorders is schizophrenia, which is a chronic, disabling, persistent, and severe brain disease that sigpiificantly impairs brain functioning and affects 1 percent of the world s population, including 3 million people in the United States alone. Antipsychotic medications are referred to as typical or atypical. Psychiatrists prescribe anxiolytics (antianxiety medications) to treat anxiety disorders, which include panic disorder, generalized anxiety disorder, specific phobias, obsessive-compulsive disorder, social anxiety disorder, and posttraumatic stress disorder. Psychiatrists prescribe antidepressants and mood stabilizers to treat the symptoms of mood disorders, the most common and severe of which are major depression and bipolar disorder. 

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