Publications by authors named "Ric M. ` Procyshyn"

Article Synopsis
  • - The study investigates the relationship between drug-induced movement disorders (DIMDs) and psychotic symptoms among homeless individuals in Vancouver, highlighting differences in how specific types of DIMDs correlate with particular psychotic symptoms.
  • - Analysis included 401 participants, revealing that parkinsonism is linked to increased negative symptoms, dyskinesia to disorganized symptoms, and akathisia to excited symptoms, but no association with depressive symptoms.
  • - Temporal associations found that delusions and unusual thoughts often precede parkinsonism, while dyskinesia leads to greater conceptual disorganization later on, emphasizing the complex interplay between these conditions in vulnerable populations.
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Housing insecurity is associated with co-occurring depression and pain interfering with daily activities. Network analysis of depressive symptoms along with associated risk or protective exposures may identify potential targets for intervention in patients with co-occurring bodily pain. In a community-based sample of adults (n = 408) living in precarious housing or homelessness in Vancouver, Canada, depressive symptoms were measured by the Beck Depression Inventory; bodily pain and impact were assessed with the 36-item Short Form Health Survey.

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Background: Up to 1/2 of outpatients prescribed clozapine may be partially/fully non-adherent, based on therapeutic drug monitoring (TDM). Three indices for measuring partial/full non-adherence are proposed a: 1) clozapine concentration/dose (C/D) ratio which drops to half or more of what is expected in the patient; 2) clozapine/norclozapine ratio that becomes inverted; and 3) clozapine concentration that becomes non-detectable.

Methods: These 3 proposed indices are based on a literature review and 17 cases of possible non-adherence from 3 samples: 1) an inpatient study in a Chinese hospital, 2) an inpatient randomized clinical trial in a United States hospital, and 3) and a Uruguayan outpatient study.

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The approach to analysis of and interpretation of findings from the Beck Depression Inventory (BDI), a self-report questionnaire, depends on sample characteristics. To extend work using conventional BDI scoring, the BDI's suitability in assessing symptom severity in a homeless and precariously housed sample was examined using Rasch analysis. Participants (n=478) recruited from an impoverished neighbourhood in Vancouver, Canada, completed the BDI.

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Antipsychotics are the only therapeutic class indicated in the symptomatic management of psychotic disorders. However, individuals diagnosed with schizophrenia or schizoaffective disorder may not always benefit from these first-line agents. This refractoriness to conventional treatment can be difficult to address in most clinical settings.

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During weak induction (from smoking and/or valproate co-prescription), clozapine ultrarapid metabolizers (UMs) need very high daily doses to reach the minimum therapeutic concentration of 350 ng/ml in plasma; clozapine UMs need clozapine doses higher than: 1) 900 mg/day in patients of European/African ancestry, or 2) 600 mg/day in those of Asian ancestry. Published clozapine UMs include 10 males of European/African ancestry, mainly assessed with single concentrations. Five new clozapine UMs (two of European and three of Asian ancestry) with repeated assessments are described.

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Objective: Many individuals living in precarious housing or homelessness have multimorbid illnesses, including substance use, psychiatric, and neurological disorders. Movement disorders (MDs) associated substance use are amongst the poorly studied subtopics of drug-induced MDs. The aim of the present study was, therefore, to determine the proportion affected and severity of different signs of MDs, as well as their associations with substance use in a community-based sample of precariously housed and homeless individuals.

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Aim: Long acting injectable (LAI) antipsychotics are an alternative to oral antipsychotic (OAP) treatment and may be beneficial for patients in the early stages of schizophrenia. This study aims to provide a comprehensive review on the efficacy of first-generation and second-generation LAI antipsychotics in recent-onset, first-episode, and early psychosis patients.

Methods: MEDLINE, EMBASE, PsycINFO, and Web of Science Core databases were used to search for studies that used LAIs in early psychosis patients.

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Pain and related consequences could contribute to comorbid illness and premature mortality in homeless and precariously housed persons. We analyzed longitudinal data from an ongoing naturalistic prospective study of a community-based sample (n = 370) to characterize risk factors and consequences of bodily pain. The aims were to describe bodily pain and associations with symptoms and psychosocial function, investigate factors that may increase or ameliorate pain, and examine the consequences of pain for symptoms, functioning, and all-cause mortality.

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The second-generation antipsychotic drugs are widely used in the field of psychiatry, for an expanding number of different conditions. While their clinical efficacy remains indispensable, many of the drugs can cause severe metabolic side-effects, resulting in an increased risk of developing cardiometabolic disorders. The physiological basis of these side-effects remains an ongoing area of investigation.

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Article Synopsis
  • This international guideline suggests enhancing clozapine package inserts by implementing ancestry-based dosing and titration to reduce adverse drug reactions (ADRs).
  • Clozapine, a powerful medication, has a narrow therapeutic range and is highly associated with toxicity, especially in certain populations; it is especially risky due to its high rates of pneumonia-related mortality.
  • The guideline outlines six personalized dosing schedules based on ancestry and metabolic activity, recommending varying daily doses of clozapine tailored to individual patient profiles to minimize the risk of ADRs.
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Article Synopsis
  • Opioid use, both prescribed and non-prescribed, is common among marginalized groups, often starting from prescribed pain medications.
  • A study interviewed 440 individuals living in precarious housing about their bodily pain and opioid use over the past month to explore the pain-opioid use relationship.
  • Results showed that factors like being female, younger age, and early exposure to opioids predicted current use, but surprisingly, there was no link between current bodily pain levels and opioid use.
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Second-generation antipsychotic medications are used to treat schizophrenia and a range of other psychotic disorders, although adverse effects, including cardiovascular and metabolic abnormalities and extrapyramidal symptoms, are often inevitable. Studies have shown that exercise, as an adjunct therapy, can be effective in reducing the core symptoms of schizophrenia as well as ameliorating intrinsic and antipsychotic-induced cardiometabolic abnormalities. However, it is noteworthy that exercise may need to be implemented with caution in some individuals receiving certain antipsychotic treatment regimens.

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The Iowa Gambling Task (IGT) is a widely used measure of decision making, but its value in signifying behaviors associated with adverse, "real-world" consequences has not been consistently demonstrated in persons who are precariously housed or homeless. Studies evaluating the ecological validity of the IGT have primarily relied on traditional IGT scores. However, computational modeling derives underlying component processes of the IGT, which capture specific facets of decision making that may be more closely related to engagement in behaviors associated with negative consequences.

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Aim: Long-acting injectable antipsychotic drugs (LAIs) are often used as an alternative to oral antipsychotics (OAPs) in individuals with psychosis who demonstrate poor medication adherence. Previous meta-analyses have found mixed results on the efficacy of LAIs, compared to OAPs, in patients with psychotic disorders. The objective of this meta-analysis was to compare the effectiveness of using LAIs versus OAPs in the early stages of psychosis.

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Early intervention is essential for favorable long-term outcomes in schizophrenia. However, there is limited guidance in the scientific literature on how best to choose between dopamine D receptor (DR) partial agonists and DR antagonists in early stages of schizophrenia. The aim of this meta-analysis was to directly compare DR partial agonists with DR antagonists for efficacy and tolerability, using randomized controlled trials (RCTs) that involved participants diagnosed with first-episode psychosis, schizophrenia, or related psychotic disorders with a duration of illness ≤5 years.

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Clozapine is a second generation antipsychotic drug that has proven to be helpful in the management of patients with psychotic disorders that are resistant to other medications. Unfortunately, the majority of patients treated with clozapine develop metabolic dysregulation, including weight gain and insulin resistance. There are few treatments available to effectively counter these side-effects.

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The second generation antipsychotic drug clozapine represents the most effective pharmacotherapy for treatment-resistant psychosis. It is also associated with low rates of extrapyramidal symptoms and hyperprolactinemia compared to other antipsychotic drugs. However, clozapine tends to be underutilized in clinical practice due to a number of disabling and serious side-effects.

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Background: Although clozapine is the gold standard for treatment-resistant schizophrenia, more than 30% of patients remain unresponsive to clozapine monotherapy and may benefit from augmentation strategies. Fluvoxamine augmentation of clozapine may be beneficial in treatment resistance because of pharmacokinetic interactions, allowing for lower clozapine dosages with higher clozapine serum levels and an increased clozapine-to-norclozapine ratio, which can modify adverse effects. An augmentation strategy using higher fluvoxamine doses may also improve persistent negative, anxiety, and obsessive-compulsive symptoms through fluvoxamine's serotonergic activity.

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Evidence supports the fact that clozapine can induce stressful obsessive-compulsive symptoms (OCS). Although clozapine's robust inhibition of serotonergic neurotransmission is believed to be a key mechanism underlying clozapine-induced OCS, the exact mechanism(s) are not fully understood. Intuitively, it is reasonable to believe that the dose of clozapine is likely related to emergent OCS severity.

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Background: The second generation antipsychotic drugs represent the most common form of pharmacotherapy for schizophrenia disorders. It is now well established that most of the second generation drugs cause metabolic side-effects. Risperidone and its active metabolite paliperidone (9-hydroxyrisperidone) are two commonly used antipsychotic drugs with moderate metabolic liability.

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Background: People living in precarious housing or homelessness have higher than expected rates of psychotic disorders, persistent psychotic symptoms, and premature mortality. Psychotic symptoms can be modeled as a complex dynamic system, allowing assessment of roles for risk factors in symptom development, persistence, and contribution to premature mortality.

Method: The severity of delusions, conceptual disorganization, hallucinations, suspiciousness, and unusual thought content was rated monthly over 5 years in a community sample of precariously housed/homeless adults ( = 375) in Vancouver, Canada.

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