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result(s) for
"Groot, Peter C."
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Critical Slowing Down as a Personalized Early Warning Signal for Depression
by
Groot, Peter C.
,
Wichers, Marieke
in
Antidepressive Agents, Second-Generation - therapeutic use
,
Aquatic Ecology and Water Quality Management
,
Aquatische Ecologie en Waterkwaliteitsbeheer
2016
About 17% of humanity goes through an episode of major depression at some point in their lifetime. Despite the enormous societal costs of this incapacitating disorder, it is largely unknown how the likelihood of falling into a depressive episode can be assessed. Here, we show for a large group of healthy individuals and patients that the probability of an upcoming shift between a depressed and a normal state is related to elevated temporal autocorrelation, variance, and correlation between emotions in fluctuations of autorecorded emotions. These are indicators of the general phenomenon of critical slowing down, which is expected to occur when a system approaches a tipping point. Our results support the hypothesis that mood may have alternative stable states separated by tipping points, and suggest an approach for assessing the likelihood of transitions into and out of depression.
Journal Article
The experience sampling method as an mHealth tool to support self‐monitoring, self‐insight, and personalized health care in clinical practice
by
Drukker, Marjan
,
Reininghaus, Ulrich
,
Viechtbauer, Wolfgang
in
Clinical medicine
,
depression
,
Ecological Momentary Assessment
2017
Background The experience sampling method (ESM) builds an intensive time series of experiences and contexts in the flow of daily life, typically consisting of around 70 reports, collected at 8–10 random time points per day over a period of up to 10 days. Methods With the advent of widespread smartphone use, ESM can be used in routine clinical practice. Multiple examples of ESM data collections across different patient groups and settings are shown and discussed, varying from an ESM evaluation of a 6‐week randomized trial of mindfulness, to a twin study on emotion dynamics in daily life. Results Research shows that ESM‐based self‐monitoring and feedback can enhance resilience by strengthening the capacity to use natural rewards. Personalized trajectories of starting or stopping medication can be more easily initiated and predicted if sensitive feedback data are available in real time. In addition, personalized trajectories of symptoms, cognitive abilities, symptoms impacting on other symptoms, the capacity of the dynamic system of mental health to “bounce back” from disturbance, and patterns of environmental reactivity yield uniquely personal data to support shared decision making and prediction in clinical practice. Finally, ESM makes it possible to develop insight into previous implicit patterns of thought, experience, and behavior, particularly if rapid personalized feedback is available. Conclusions ESM enhances clinical practice and research. It is empowering, providing co‐ownership of the process of diagnosis, treatment evaluation, and routine outcome measurement. Blended care, based on a mix of face‐to‐face and ESM‐based outside‐the‐office treatment, may reduce costs and improve outcomes.
Journal Article
Outcomes of hyperbolic tapering of antidepressants
by
Groot, Peter C.
,
van Os, Jim
in
Antidepressants
,
Clinical medicine
,
Discontinuing Psychotropic Medications
2023
Background:
In patients attempting to discontinue their antidepressant medication, there have been no prospective studies on patterns of withdrawal as a function of the rate of antidepressant reduction during the tapering trajectory, and moderators thereof.
Objective:
To investigate withdrawal as a function of gradual dose reduction.
Design:
Prospective cohort study.
Methods:
The sampling frame consisted of 3956 individuals in the Netherlands who received an antidepressant tapering strip between 19 May 2019 and 22 March 2022 in routine clinical practice. Of these, 608 patients, majorly with previous unsuccessful attempts to stop, provided daily ratings of withdrawal in the context of reducing their antidepressant medications (mostly venlafaxine or paroxetine), using hyperbolic tapering strips offering daily tiny reductions in dose.
Results:
Withdrawal in daily-step hyperbolic tapering trajectories was limited, and inverse to the rate of taper. Female sex, younger age, presence of one or more risk factors and faster rate of reduction over shorter tapering trajectories were associated with more withdrawal and differential course over time. Thus, sex and age differences were less marked early in the course of the trajectory, whereas differences associated with risk factors and shorter trajectories tended to peak early in the trajectory. There was evidence that tapering in weekly larger steps (mean per-week dose reduction: 33.4% of previous dose), in comparison with daily tiny steps (mean per-day dose reduction: 4.5% of previous dose or 25.3% per week), was associated with more withdrawal in trajectories of 1, 2 or 3 months, particularly for paroxetine and the group of other (non-paroxetine, non-venlafaxine) antidepressants.
Conclusion:
Antidepressant hyperbolic tapering is associated with limited, rate-dependent withdrawal that is inverse to the rate of taper. The demonstration of multiple demographic, risk and complex temporal moderators in time series of withdrawal data indicates that antidepressant tapering in clinical practice requires a personalised process of shared decision making over the entire course of the tapering period.
Journal Article
How user knowledge of psychotropic drug withdrawal resulted in the development of person-specific tapering medication
by
Groot, Peter C.
,
van Os, Jim
in
Discontinuing Psychotropic Medications
,
Drug withdrawal
,
Psychotropic drugs
2020
Coming off psychotropic drugs can cause physical as well as mental withdrawal, resulting in failed withdrawal attempts and unnecessary long-term drug use. The first reports about withdrawal appeared in the 1950s, but although patients have been complaining about psychotropic withdrawal problems for decades, the first tentative acknowledgement by psychiatry only came in 1997 with the introduction of the ‘antidepressant-discontinuation syndrome’. It was not until 2019 that the UK Royal College of Psychiatrists, for the first time, acknowledged that withdrawal can be severe and persistent. Given the lack of a systematic professional response, over the years, patients who were experiencing withdrawal started to work out practical ways to safely come off medications themselves. This resulted in an experience-based knowledge base about withdrawal which ultimately, in The Netherlands, gave rise to the development of person-specific tapering medication (so-called tapering strips). Tapering medication enables doctors, for the first time, to flexibly prescribe and adapt the medication required for responsible and person-specific tapering, based on shared decision making and in full agreement with recommendations in existing guidelines. Looking back, it is obvious that the simple practical solution of tapering strips could have been introduced much earlier, and that the traditional academic strategy of comparisons from randomised trials is not the logical first step to help individual patients. While randomised controlled trials (RCTs) are the gold standard for evaluating interventions, they are unable to accommodate the heterogeneity of individual responses. Thus, a more individualised approach, building on RCT knowledge, is required. We propose a roadmap for a more productive way forward, in which patients and academic psychiatry work together to improve the recognition and person-specific management of psychotropic drug withdrawal.
Journal Article
Successful use of tapering strips for hyperbolic reduction of antidepressant dose: a cohort study
2021
Background:
Tapering strips facilitate antidepressant discontinuation, allowing for personalised titration of discontinuation to the intensity of withdrawal. A tapering strip consists of antidepressant or other medication, packaged in a 28-day roll of daily pouches, each with the same or slightly lower dose than the one before. Previous studies demonstrated 70% real-world effectiveness of tapering strips. Here, we present a third, questionnaire-based retrospective cohort study in a large sample.
Methods:
Patients whose doctor had prescribed tapering strips between October 2015 and December 2018 were sent a questionnaire for participation after completion of tapering between December 2015 and January 2020. Of 1240 individuals who returned a questionnaire (response rate: 59%), 987 (80%) used an antidepressant, of whom 824 (83%) had wished to discontinue their antidepressant.
Results:
The sample was demographically representative of antidepressant users in the Netherlands. Less than 40% of participants had heard of tapering strips through their clinicians – Internet was the most frequent source. Of the 824 individuals, 341 (41%) had used strips for tapering venlafaxine, 206 (25%) for paroxetine and 277 (34%) for other antidepressants. Median duration of antidepressant use was 5–10 years, and most (71%) had tried to come off without tapering strips at least once. Most patients (72%) were able to discontinue their antidepressant, using a median of two strips to taper over a median period of 56 days. Females and individuals with (1) more severe experience of withdrawal during the use of tapering strips, (2) more years of use of antidepressant medication and (3) more previous attempts at discontinuation were less likely to be able to discontinue their antidepressant medication with tapering strips.
Conclusion:
The results of this study validate, for the third time, the observation that tapering strips can address the problem of antidepressant withdrawal symptoms in individuals attempting to discontinue antidepressants.
Journal Article
Outcome of antidepressant drug discontinuation with taperingstrips after 1–5 years
2020
Background:
Stopping antidepressants is often difficult due to withdrawal. Taperingstrips were developed to facilitate antidepressant discontinuation according to the recently described Horowitz-Taylor method, allowing for personalised titration of discontinuation to the intensity of withdrawal. A taperingstrip consists of antidepressant or other medication, packaged in a 28-day roll of small daily pouches, each with the same or slightly lower dose than the one before it. We previously reported that the short-term success rate of antidepressant taperingstrips was 71%. Here, we examine longer-term outcome after 1–5 years.
Methods:
Patients whose doctor had ordered taperingstrips between January 2015 and December 2019 were sent a questionnaire for participation in anonymised research in January 2020. Of 1012, 483 participated, of whom 408 (85%) had attempted antidepressant tapering.
Results:
Of the 408 patients included, 192 (47%) had used strips for tapering venlafaxine, 142 (35%) for paroxetine and 74 (18%) for other antidepressants. Median length of antidepressant use was 4 years, and most (61%) had tried to come off without taperingstrips at least once. After 1–5 years, 270 patients (66%) remained off antidepressants after tapering their antidepressant, 6 (2%) had successfully reduced their medication, 87 (21%) had restarted due to (self-reported) relapse, 35 had restarted for another indication (9%), and 10 (3%) reported another outcome. People with more severe experience of withdrawal prior to tapering, and people who had been on antidepressants for a shorter period of time, were more likely to remain off medication after 1–5 years.
Conclusion:
The previously reported 71% short-term success rate of taperingstrips in the most severely affected group, was matched by a 68% rate after 1–5 years. The evidence-based approach of personal tapering to counter withdrawal, as used for drugs causing withdrawal, for example, benzodiazepines, may represent a simple solution for an important antidepressant-related public health problem, without extra costs.
Journal Article
Canadian polar bear population structure using genome‐wide markers
by
Groot, Peter V. C.
,
Jensen, Evelyn L.
,
Branigan, Marsha
in
Animal populations
,
Aquatic mammals
,
Arctic
2020
Predicting the consequences of environmental changes, including human‐mediated climate change on species, requires that we quantify range‐wide patterns of genetic diversity and identify the ecological, environmental, and historical factors that have contributed to it. Here, we generate baseline data on polar bear population structure across most Canadian subpopulations (n = 358) using 13,488 genome‐wide single nucleotide polymorphisms (SNPs) identified with double‐digest restriction site‐associated DNA sequencing (ddRAD). Our ddRAD dataset showed three genetic clusters in the sampled Canadian range, congruent with previous studies based on microsatellites across the same regions; however, due to a lack of sampling in Norwegian Bay, we were unable to confirm the existence of a unique cluster in that subpopulation. These data on the genetic structure of polar bears using SNPs provide a detailed baseline against which future shifts in population structure can be assessed, and opportunities to develop new noninvasive tools for monitoring polar bears across their range. With ongoing rapid sea ice loss and environmental change in the Arctic, there is the potential for rapid changes in polar bear population structure. Here, we generated baseline data on polar bear population structure across 12 of 13 Canadian subpopulations using genome‐wide SNPs. These data on the genetic structure of polar bears using SNPs provide a detailed baseline against which future shifts in population structure can be assessed, and opportunities to develop new noninvasive tools for monitoring polar bears across their range.
Journal Article
A new multiplexed magnetic capture—Droplet digital PCR tool for monitoring wildlife population health and pathogen surveillance
by
Dyck, Markus
,
Sun, Zhengxin
,
V. C. de Groot, Peter
in
Animal health
,
Animal populations
,
Anthropogenic factors
2023
Anthropogenic stressors are exacerbating the emergence and spread of pathogens worldwide. In regions like the Arctic, where ecosystems are particularly susceptible, marked changes are predicted in regional diversity, intensity, and patterns of infectious diseases. To understand such rapidly changing host‐pathogen dynamics and mitigate the impacts of novel pathogens, we need sensitive disease surveillance tools. We developed and validated a novel multiplexed, magnetic capture, and ddPCR tool for the surveillance of multiple pathogens in polar bears, a sentinel species that is considered susceptible to climate change and other stressors with a pan‐Arctic distribution. Through sequence‐specific magnetic capture, we concentrated five target template sequences from three zoonotic bacteria (Erysipelothrix rhusiopathiae, Francisella tularensis, and Mycobacterium tuberculosis complex) and two parasitic (Toxoplasma gondii and Trichinella spp.) pathogens from large quantities (<100 g) of host tissue. We then designed and validated two multiplexed probe‐based ddPCR assays for the amplification and detection of the low‐concentration target DNA. Validations used 48 polar bear tissues (muscle and liver). We detected 14, 1, 3, 4, and 22 tissue positives for E. rhusiopathiae, F. tularensis, M. tuberculosis complex, T. gondii, and Trichinella spp., respectively. These multiplexed assays offer a rapid, specific tool for quantifying and monitoring the changing geographical and host distributions of pathogens relevant to human and animal health. Climate change is altering the distributions of many species, including pathogens and their hosts. We have developed new magnetic capture and multiplexed digital droplet PCR assays to detect the presence of three bacterial pathogens and two parasites in polar bear tissues from across the Canadian Arctic. We validate our assays and suggest how these new powerful assays can meaningfully contribute to community‐based monitoring of pathogens in polar bears and other wildlife.
Journal Article
Characterization of skin- and intestine microbial communities in migrating High Arctic lake whitefish and cisco
by
Hamilton, Erin F.
,
Engel, Katja
,
Casselman, John M.
in
Aquaculture
,
Bar codes
,
Community composition
2024
At high latitudes, lake whitefish ( Coregonus clupeaformis) and others in the closely related Coregonus species complex (CSC) including cisco ( C. autumnalis and C. sardinella) can be diadromous, seasonally transitioning between freshwater lakes and the Arctic Ocean. CSC skin- and intestine microbiomes were collected, facilitated by Inuit fishers at sites on and around King William Island, Nunavut, at the northern range limits of lake whitefish. Community composition was explored using 16S rRNA gene sequencing and microbiota distinctly grouped depending on fishing site salinity. Overall, lake whitefish intestine communities were more variable than those of the two cisco with higher Shannon diversity, suggesting that lake whitefish and their microbiomes could be susceptible to environmental stress possibly leading to dysbiosis. Lake whitefish showed lower condition (K) in the ocean than in freshwater rivers, whereas cisco condition was similar among distinct seasonal habitats. Taken together, the impact of changing habitats on fish condition and microbial composition may inform approaches to CSC health in fisheries and aquaculture, in addition to being relevant for northern Indigenous peoples with subsistence and economic interests in these resources.
Journal Article
Ptprj is a candidate for the mouse colon-cancer susceptibility locus Scc1 and is frequently deleted in human cancers
by
van Zandwijk, Nico
,
Klous, Anita M.
,
Csikós, Tamás
in
Adenocarcinoma - genetics
,
Adenocarcinoma - pathology
,
Agriculture
2002
Only a small proportion of cancers result from familial cancer syndromes with Mendelian inheritance. Nonfamilial, 'sporadic' cancers, which represent most cancer cases, also have a significant hereditary component
1
,
2
, but the genes involved have low penetrance and are extremely difficult to detect
2
,
3
. Therefore, mapping and cloning of quantitative trait loci (QTLs) for cancer susceptibility in animals could help identify homologous genes in humans. Several cancer-susceptibility QTLs have been mapped in mice and rats
4
,
5
, but none have been cloned so far. Here we report the positional cloning of the mouse gene
Scc1
(Susceptibility to colon cancer 1)
6
and the identification of
Ptprj
, encoding a receptor-type protein tyrosine phosphatase, as the underlying gene. In human colon, lung and breast cancers, we show frequent deletion of
PTPRJ
, allelic imbalance in loss of heterozygosity (LOH) and missense mutations. Our data suggest that
PTPRJ
is relevant to the development of several different human cancers.
Journal Article