Symptom clusters

Neurobiology of recurrence distinct from that of specific symptom clusters ... 

Schizophrenia is characterized by three partially independent symptom clusters 875... 

Schizophrenia is characterized by three partially independent symptom clusters. These symptom clusters are designated positive symptoms, negative symptoms and cognitive impairments [1], The positive symptoms are the most dramatic and are manifestations of psychosis. 

The second revolution began in the past 10 years with the arrival of the atypical antipsychotics. Although the atypicals are no panacea for schizophrenia, they represent an advance in at least three areas. First, they lessen the burden of antipsychotic side effects and therefore frequently increase adherence dramatically. Second, the atypicals may treat all of the schizophrenia symptom clusters (positive, negative, mood, cognitive), whereas the typical antipsychotics chiefly treat the positive symptoms. Third, atypical antipsychotics sometimes benefit patients whose schizophrenia is unresponsive to typical antipsychotics. 

The symptoms of PTSD are grouped into three symptom clusters (1) reexperiencing symptoms, (2) avoidance/numbing symptoms, and (3) hyperarousal symptoms. To fulfill the diagnostic criteria for PTSD, these symptoms must have persisted... 

PTSD pharmacotherapy has been an area of intense research interest over the past decade. This has been complemented by a plethora of studies regarding the neurobiology of the disorder that may ultimately serve to inform the development and refinement of novel therapies. Pharmacotherapy is used to target one or more of the main PTSD symptom clusters, that is, reexperiencing symptoms, avoidance/numbing symptoms, and hyperarousal symptoms. 

The cardinal features of PTSD include initial exposure to a traumatic event, with the subsequent development of three symptom clusters reexperiencing of the trauma, avoidance behavior, and hyperarousal. The DSM-IV (American Psychiatric Association, 1994) criteria state that the A-criterion for PTSD, traumatic exposure, involves experiencing, witnessing, or being confronted with an event that is life threatening or involves serious threat or injury to oneself or others. 

Pharmacological Activity Specific Agent Dose Range PTSD Symptom Cluster, Remarks... 

Benzodiazepine Alprazolam Clonazepam 0.25-6 mg/day 0.5-6 mg/day Reduces anxiety, insomnia little effect on core PTSD symptom clusters... 

Anticonvulsant Carbamazepine Valproic acid 200-1000 mg/day 125-1750 mg/day Cluster B and C symptoms Cluster B and D symptoms... 

In cases of SSRI nonresponse, consideration should be given to using venlafaxine and nefazadone, as these agents appear to be safe and have consensus support for their use. Table 43.2 provides further detailed guidelines in matching specific pharmacological agents with PTSD symptom clusters. 

Analysis of BPRS factor scores showed that treatment with quetiapine resulted in selective improvement in the psychosis-related factors of thought disturbance and hostility/suspiciousness, as well as improvement in the mean BPRS positive-symptoms cluster score. By day 21, quetiapine was clinically and statistically superior to placebo in moderating negative symptoms. 

Presently, most experts recommend the SSRIs as a first-line medication for PTSD despite their troublesome adverse effects. These drugs can alleviate PTSD symptom clusters, anxiety, and depression, as well as dissociative symptoms, as shown in an open-label trial by Marshall et al. ( 276). 

Trazodone Preliminary data suggest that trazodone may be effective in reducing the three primary symptom clusters of PTSD. These findings, however, need to be confirmed in a double-blind, placebo-controlled, larger sample size study ( 282). 

The authors observed that between one-third and one-half of head injury victims experience this symptom cluster over the first few weeks and a substantial minority continue to experience it for months or a year or more. 

Dayal H, Gupta S, Triefif N, et al. 1995. Symptom clusters in a community with chronic exposure to chemicals in two superfund sites. Archives Of Environmental Health 50 (2) 108-111. 

For each of these three symptom clusters, there is a specific algorithm of treatment, sequencing various antidepressants, mood stabilizers, and antipsychotics in varying orders of preference, doses, and combinations of use. 

In addition, at least one symptom from each of the three symptom clusters required for PTSD is also present ... 

Schizophrenia is a debilitating disorder affecting 1 % of the global population. It is a pervasive disease, affecting many aspects of mental function. Positive, negative, affective, and cognitive symptom clusters characterize schizophrenia (Table 1). 

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