Force Feedback Controls Motor Activity and Mechanical Properties of Self-Assembling Branched Actin Networks.

Branched actin networks--created by the Arp2/3 complex, capping protein, and a nucleation promoting factor--generate and transmit forces required for many cellular processes, but their response to force is poorly understood. To address this, we assembled branched actin networks in vitro from purified components and used simultaneous fluorescence and atomic force microscopy to quantify their molecular composition and material properties under various forces. Remarkably, mechanical loading of these self-assembling materials increases their density, power, and efficiency. Microscopically, increased density reflects increased filament number and altered geometry but no change in average length. Macroscopically, increased density enhances network stiffness and resistance to mechanical failure beyond those of isotropic actin networks. These effects endow branched actin networks with memory of their mechanical history that shapes their material properties and motor activity. This work reveals intrinsic force feedback mechanisms by which mechanical resistance makes self-assembling actin networks stiffer, stronger, and more powerful.

A minimal midzone protein module controls formation and length of antiparallel microtubule overlaps.

During cell division, microtubules are arranged in a large bipolar structure, the mitotic spindle, to segregate the duplicated chromosomes. Antiparallel microtubule overlaps in the spindle center are essential for establishing bipolarity and maintaining spindle stability throughout mitosis. In anaphase, this antiparallel microtubule array is tightly bundled forming the midzone, which serves as a hub for the recruitment of proteins essential for late mitotic events. The molecular mechanism of midzone formation and the control of its size are not understood. Using an in vitro reconstitution approach, we show here that PRC1 autonomously bundles antiparallel microtubules and recruits Xklp1, a kinesin-4, selectively to overlapping antiparallel microtubules. The processive motor Xklp1 controls overlap size by overlap length-dependent microtubule growth inhibition. Our results mechanistically explain how the two conserved, essential midzone proteins PRC1 and Xklp1 cooperate to constitute a minimal protein module capable of dynamically organizing the core structure of the central anaphase spindle.

One-Day Peer-Delivered Cognitive Behavioral Therapy-Based Workshops for Postpartum Depression: A Randomized Controlled Trial.

INTRODUCTION: Myriad treatment barriers prevent birthing parents with postpartum depression (PPD) from receiving timely treatment. We aimed to determine whether a peer-delivered online 1-day cognitive behavioral therapy (CBT)-based workshop added to treatment as usual (TAU) improves PPD and its comorbidities and is more cost-effective than TAU alone. METHODS: This parallel-group, randomized controlled trial took place in Ontario, Canada (June 7, 2021, to February 18, 2022). Participants were ≥18 years old, had an infant ≤12 months old, and an Edinburgh Postnatal Depression Scale (EPDS) score ≥10. Participants were allocated to receive the workshop plus TAU (n = 202) or TAU and waitlisted to complete the workshop 12 weeks later (n = 203). The primary outcome was change in PPD (EPDS score) from enrollment to 12 weeks later. The secondary outcome was cost-effectiveness and tertiary outcomes included anxiety, social support, partner relationship quality, the mother-infant relationship, parenting stress, and infant temperament. RESULTS: Participants had a mean age of 32.3 years (SD = 4.30) and 65% were White. The workshop led to a significant reduction in EPDS scores (15.95-11.37; d = 0.92, p < 0. 01) and was associated with higher odds of exhibiting a clinically significant decrease in EPDS scores (OR = 2.03; 95% CI: 1.26-3.29). The workshop plus TAU was more cost-effective than TAU alone. It also led to improvements in postpartum anxiety, infant-focused anxiety, parenting stress, and infant temperament. CONCLUSIONS: Peer-delivered 1-day CBT-based workshops can improve PPD and are a potentially scalable low-intensity treatment that could help increase treatment access.

Therapist-guided remote versus in-person cognitive behavioural therapy: a systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Cognitive behavioural therapy (CBT) has been shown to be effective for several psychiatric and somatic conditions; however, most randomized controlled trials (RCTs) have administered treatment in person and whether remote delivery is similarly effective remains uncertain. We sought to compare the effectiveness of therapist-guided remote CBT and in-person CBT. METHODS: We systematically searched MEDLINE, Embase, PsycINFO, CINAHL, and the Cochrane Central Register of Controlled Trials from inception to July 4, 2023, for RCTs that enrolled adults (aged ≥ 18 yr) presenting with any clinical condition and that randomized participants to either therapist-guided remote CBT (e.g., teleconference, videoconference) or in-person CBT. Paired reviewers assessed risk of bias and extracted data independently and in duplicate. We performed random-effects model meta-analyses to pool patient-important primary outcomes across eligible RCTs as standardized mean differences (SMDs). We used Grading of Recommendations Assessment, Development and Evaluation (GRADE) guidance to assess the certainty of evidence and used the Instrument to Assess the Credibility of Effect Modification Analyses (ICEMAN) to rate the credibility of subgroup effects. RESULTS: We included 54 RCTs that enrolled a total of 5463 patients. Seventeen studies focused on treatment of anxiety and related disorders, 14 on depressive symptoms, 7 on insomnia, 6 on chronic pain or fatigue syndromes, 5 on body image or eating disorders, 3 on tinnitus, 1 on alcohol use disorder, and 1 on mood and anxiety disorders. Moderate-certainty evidence showed little to no difference in the effectiveness of therapist-guided remote and in-person CBT on primary outcomes (SMD -0.02, 95% confidence interval -0.12 to 0.07). INTERPRETATION: Moderate-certainty evidence showed little to no difference in the effectiveness of in-person and therapist-guided remote CBT across a range of mental health and somatic disorders, suggesting potential for the use of therapist-guided remote CBT to facilitate greater access to evidence-based care. Systematic review registration: Open Science Framework (https://osf.io/7asrc).

Transient Structural Properties of the Rho GDP-Dissociation Inhibitor.

Rho GTPases, master spatial regulators of a wide range of cellular processes, are orchestrated by complex formation with guanine nucleotide dissociation inhibitors (RhoGDIs). These have been thought to possess an unstructured N-terminus that inhibits nucleotide exchange of their client upon binding/folding. Via NMR analyses, molecular dynamics simulations, and biochemical assays, we reveal instead pertinent structural properties transiently maintained both, in the presence and absence of the client, imposed onto the terminus context-specifically by modulating interactions with the surface of the folded C-terminal domain. These observations revise the long-standing textbook picture of the GTPases' mechanism of membrane extraction. Rather than by a disorder-to-order transition upon binding of an inhibitory peptide, the intricate and highly selective extraction process of RhoGTPases is orchestrated via a dynamic ensemble bearing preformed transient structural properties, suitably modulated by the specific surrounding along the multi-step process.

In-person 1-day cognitive behavioral therapy-based workshops for postpartum depression: a randomized controlled trial.

BACKGROUND: Postpartum depression (PPD) affects up to one in five mothers and birthing parents, yet as few as 10% access evidence-based treatment. One-day cognitive behavioral therapy (CBT)-based workshops for PPD have the potential to reach large numbers of sufferers and be integrated into stepped models of care. METHODS: This randomized controlled trial of 461 mothers and birthing parents in Ontario, Canada with Edinburgh Postnatal Depression Scale (EPDS) scores ⩾10, age ⩾18 years, and an infant <12 months of age compared the effects of a 1-day CBT-based workshop plus treatment as usual (TAU; i.e. care from any provider(s) they wished) to TAU alone at 12-weeks post-intervention on PPD, anxiety, the mother-infant relationship, offspring behavior, health-related quality of life, and cost-effectiveness. Data were collected via REDCap. RESULTS: Workshops led to meaningful reductions in EPDS scores (m = 15.77 to 11.22; b = -4.6, p < 0.01) and were associated with three times higher odds of a clinically significant decrease in PPD [odds ratio (OR) 3.00, 95% confidence interval (CI) 1.93-4.67]. Anxiety also decreased and participants had three times the odds of clinically significant improvement (OR 3.20, 95% CI 2.03-5.04). Participants reported improvements in mother-infant bonding, infant-focused rejection and anger, and effortful control in their toddlers. The workshop plus TAU achieved similar quality-adjusted life-years at lower costs than TAU alone. CONCLUSIONS: One-day CBT-based workshops for PPD can lead to improvements in depression, anxiety, and the mother-infant relationship and are cost-saving. This intervention could represent a perinatal-specific option that can treat larger numbers of individuals and be integrated into stepped care approaches at reasonable cost.

Online peer-delivered group cognitive-behavioral therapy for postpartum depression: A randomized controlled trial.

BACKGROUND: Postpartum depression (PPD) affects up to one in five mothers and birthing parents, yet just 10% receive evidence-based care. This randomized controlled trial aimed to determine if a synchronous online 9-week group cognitive-behavioral therapy (CBT) intervention delivered by mothers who have recovered from postpartum depression (i.e., peers) could effectively improve PPD and its comorbidities. METHODS: Participants (n = 183) in this study lived in Ontario, Canada, were ≥18 years-old, had an infant <12 months, were fluent in English, and scored ≥10 on the Edinburgh Postnatal Depression Scale (EPDS). They were randomized to experimental (received intervention plus treatment as usual (TAU)) or waitlist control (TAU plus the intervention after a 9-week wait) groups. Depression, anxiety, social support, mother-infant bonding, and infant temperament were assessed at baseline and 9 weeks later. Outcomes were assessed in the experimental group 3 months post-intervention to assess stability. RESULTS: Statistically significant reductions were observed in EPDS (B = 5.99; p < 0.001; d = 1.32) and Generalized Anxiety Disorder Questionnaire-7 scores (B = 5.94; p < 0.001; d = 1.22), improvements that remained stable 3 months post-intervention in the experimental group. Maternal social support (p = 0.02; d = 0.40), infant-focused anxiety (p = 0.02; d = 0.54), and infant negative emotionality (p < 0.01; d = 0.23) also improved post-intervention and remained stable 3 months later. CONCLUSION: Online peer-delivered group CBT for PPD can effectively treat PPD and anxiety, and improve social support, infant-focused anxiety, and negative emotionality in infants. This intervention could provide the means to increase access to treatment for those experiencing PPD and improve outcomes for mothers, birthing parents, and families.

Fidelity Assessment of Peer-Delivered Cognitive-Behavioral Therapy for Postpartum Depression.

OBJECTIVE: Fidelity assessment of peer-administered interventions (PAIs) by expert therapists can be costly and limit scalability. This study's objective was to determine whether peer facilitators could assess the fidelity of peer-delivered group cognitive-behavioral therapy (CBT) for postpartum depression as effectively as an expert psychiatrist or a trained graduate student. METHODS: Intervention adherence and competence were assessed by three peers (N=9 sessions) and by one expert psychiatrist and one graduate student (N=18 sessions). Interrater reliability was assessed with intraclass correlation coefficients (ICCs). RESULTS: ICCs were good to excellent (0.88-0.98) for adherence and competence ratings among the three types of raters (psychiatrist vs. peers, psychiatrist vs. student, and student vs. peers). CONCLUSIONS: Trained peers may be able to reliably rate the fidelity of a PAI for postpartum depression. This preliminary study represents the first step toward peer-led feedback as an alternative to expert-led supervision of peer-delivered group CBT for postpartum depression.

WH2 and proline-rich domains of WASP-family proteins collaborate to accelerate actin filament elongation.

WASP-family proteins are known to promote assembly of branched actin networks by stimulating the filament-nucleating activity of the Arp2/3 complex. Here, we show that WASP-family proteins also function as polymerases that accelerate elongation of uncapped actin filaments. When clustered on a surface, WASP-family proteins can drive branched actin networks to grow much faster than they could by direct incorporation of soluble monomers. This polymerase activity arises from the coordinated action of two regulatory sequences: (i) a WASP homology 2 (WH2) domain that binds actin, and (ii) a proline-rich sequence that binds profilin-actin complexes. In the absence of profilin, WH2 domains are sufficient to accelerate filament elongation, but in the presence of profilin, proline-rich sequences are required to support polymerase activity by (i) bringing polymerization-competent actin monomers in proximity to growing filament ends, and (ii) promoting shuttling of actin monomers from profilin-actin complexes onto nearby WH2 domains. Unoccupied WH2 domains transiently associate with free filament ends, preventing their growth and dynamically tethering the branched actin network to the WASP-family proteins that create it. Collaboration between WH2 and proline-rich sequences thus strikes a balance between filament growth and tethering. Our work expands the number of critical roles that WASP-family proteins play in the assembly of branched actin networks to at least three: (i) promoting dendritic nucleation; (ii) linking actin networks to membranes; and (iii) accelerating filament elongation.

Naturalistic Study on the Effects of Electroconvulsive Therapy (ECT) on Depressive Symptoms.

OBJECTIVE: The effectiveness of ECT under naturalistic conditions has not been well-studied. The current study aimed to 1) characterize a naturalistic sample of ECT patients; and 2) examine the long-term outcomes of ECT on depressive symptoms (Beck Depression Inventory-II; BDI-II) and functional disability symptoms (WHO Disability Assessment Schedule 2.0) in this sample. METHODS: Participants were adults who received ECT for a major depressive episode at an ambulatory ECT clinic between September 2010 and November 2020. Clinical and cognitive assessments were completed at baseline (n = 100), mid-ECT (n = 94), 2-4 weeks post-ECT (n = 64), 6-months post-ECT (n = 34), and 12-months post-ECT (n = 19). RESULTS: At baseline, participants had severe levels of depressive symptoms (BDI-II: M = 41.0, SD = 9.4), and 62.9% screened positive for multiple psychiatric diagnoses on the MINI International Neuropsychiatric Interview. Depressive symptoms (F(4,49.1) = 49.92, P < 0.001) and disability symptoms (F(3,40.72) = 12.30, P < 0.001) improved significantly following ECT, and this was maintained at 12-months follow-up. Improvement in depressive symptoms trended towards significantly predicting reduction in disability symptoms from baseline to post-ECT, (F(1,56) = 3.67, P = 0.061). Although our clinical remission rate of 27% (BDI-II score ≤ 13 and ≥ 50% improvement) and overall response rate of 41.3% (≥50% improvement in BDI-II score) were lower than the rates reported in the extant RCT and community ECT literature, 36% of those treated with ECT were lost to follow-up and did not complete post-ECT rating scales. At baseline, remitters had significantly fewer psychiatric comorbidities, lower BDI-II scores, and lower disability symptoms than non-responders (P < 0.05). CONCLUSIONS: Participants were severely symptomatic and clinically complex. ECT was effective at reducing depressive symptoms and functional disability in this heterogeneous sample. Although a large amount of missing data may have distorted our calculated response/remission rates, it is also likely that clinical heterogeneity and severity contribute to lower-than-expected remission and response rates to ECT.

Public Health Nurse-delivered Group Cognitive Behavioural Therapy for Postpartum Depression: A Randomized Controlled Trial.

OBJECTIVES: To examine the effectiveness of group cognitive behavioural therapy (CBT) for postpartum depression (PPD) delivered by public health nurses with little to no previous psychiatric training at improving depression, worry, social support and the mother-infant relationship. METHODS: Mothers (n = 141) living in Ontario, Canada with Edinburgh Postnatal Depression Scale Scores ≥10 and an infant <12 months of age were randomized to receive nine weekly 2-h sessions of in-person group CBT for PPD delivered by two public health nurses plus treatment as usual (TAU; experimental group) or TAU alone (control group). Primary outcomes were change in EPDS score and current major depressive disorder (Mini International Neuropsychiatric Interview) assessed immediately post-treatment (T2). Secondary outcomes included maternal worry, social support, and quality of the mother-infant relationship. All outcomes were assessed again six months post-treatment (T3). RESULTS: Participants in the experimental group had statistically significantly greater reductions in PPD symptoms immediately post-treatment (T2) (B = -5.35, p < 0.01), were more likely to manifest a clinically significant improvement in EPDS scores (≥4 points; OR = 3.44, 95%CI: 1.49-7.94), and no longer have symptoms consistent with current MDD (OR = 5.31, 95% CI: 1.78-15.83). Six months post-treatment (T3), experimental group participants had higher odds of clinically significant PPD improvement (OR = 5.10, 95%CI: 1.89-13.78), while 25% of the experimental group and 70% of remaining control group participants reported current MDD (p < 0.01). Statistically significant improvements in worry and the mother-infant relationship were also observed, decreases maintained at six months post-treatment. CONCLUSIONS: Public health nurses with little to no previous psychiatric training can be trained to deliver effective group CBT for PPD to improve depression, worry, and the mother-infant relationship. Task shifting PPD treatment with group CBT to public health nurses could improve treatment uptake and lead to better outcomes for mothers, families, and the healthcare system.(Trial Registration NCT03039530).

Stochastic geometry sensing and polarization in a lipid kinase-phosphatase competitive reaction.

Phosphorylation reactions, driven by competing kinases and phosphatases, are central elements of cellular signal transduction. We reconstituted a native eukaryotic lipid kinase-phosphatase reaction that drives the interconversion of phosphatidylinositol-4-phosphate [PI(4)P] and phosphatidylinositol-4,5-phosphate [PI(4,5)P2] on membrane surfaces. This system exhibited bistability and formed spatial composition patterns on supported membranes. In smaller confined regions of membrane, rapid diffusion ensures the system remains spatially homogeneous, but the final outcome-a predominantly PI(4)P or PI(4,5)P2 membrane composition-was governed by the size of the reaction environment. In larger confined regions, interplay between the reactions, diffusion, and confinement created a variety of differentially patterned states, including polarization. Experiments and kinetic modeling reveal how these geometric confinement effects arise from a mechanism based on stochastic fluctuations in the copy number of membrane-bound kinases and phosphatases. The underlying requirements for such behavior are unexpectedly simple and likely to occur in natural biological signaling systems.

An Examination of the Performance of the interRAI Risk of Harm to Others Clinical Assessment Protocol (RHO CAP) in Inpatient Mental Health Settings.

We study violence risk prediction at St. Joseph's Healthcare Hamilton. Data from January 2016 to December 2017 have been anonymized and collected, for a total of 870 episodes of inpatient aggressions perpetrated by 337 patients. We examine the predictive performance of a clinical indicator embedded in a mandatory assessment tool for psychiatric facilities in Ontario, the Resident Assessment Instrument for Mental Health (RAI-MH): the Risk of Harm to Others Clinical Assessment Protocol (RHO CAP). The RHO CAP's performance is studied among two groups of patients. Moreover, an analysis of the most important risk factors associated with harmful incidents is presented. The RHO CAP has demonstrated a better performance in discriminating which patients were more at risk to commit some type of aggression than at identifying the risk of harm among those who will commit aggression.

A Predictive Model for Estimating Risk of Harm and Aggression in Inpatient Mental Health Clinics.

Serious mental illness is a major risk factor for aggression and violence. The present study aimed to develop and test an algorithm to predict inpatient aggressions that involve a risk of harm to self or others. This work is based on a retrospective study aimed to investigate the prediction of risk of harm and aggressions at St. Joseph's Healthcare Hamilton, between 2016 and 2017. An analysis of the risk factors most strongly associated with harmful incidents is, followed by the description of the process involved in the development of a predictive model which estimates the risk of harm. The efficiency of the model developed is finally evaluated, showing an overall accuracy of 75%: the specificity to identify episodes considered not at risk of harm is equal to 91.85%, whereas the sensitivity to identify episodes considered harmful is equal to 28.57%. The model proposed can be seen as a seminal project towards the development of a more comprehensive, precise and effective tool capable to predict the risk of harm in the inpatient setting.

Cryo-EM Resolves Molecular Recognition Of An Optojasp Photoswitch Bound To Actin Filaments In Both Switch States.

Actin is essential for key processes in all eukaryotic cells. Cellpermeable optojasps provide spatiotemporal control of the actin cytoskeleton, confining toxicity and potentially rendering F-actin druggable by photopharmacology. Here, we report cryo electron microscopy (cryo-EM) structures of both isomeric states of one optojasp bound to actin filaments. The high-resolution structures reveal for the first time the pronounced effects of photoswitching a functionalized azobenzene. By characterizing the optojasp binding site and identifying conformational changes within F-actin that depend on the optojasp isomeric state, we refine determinants for the design of functional F-actin photoswitches.

Public health nurses' experiences learning and delivering a group cognitive behavioral therapy intervention for postpartum depression.

OBJECTIVES: Public Health Nurses (PHNs) often provide support to women with postpartum depression (PPD) in the absence of specialized training. The objective of this study was to explore the experiences of six PHNs who were trained to deliver a group cognitive behavioral therapy (CBT) intervention for PPD in the public health setting, and to describe how learning and delivering this intervention affected their professional roles and personal lives. DESIGN: This qualitative study employed a phenomenological approach. SAMPLE: Six PHNs who completed the CBT training program and delivered at least one CBT group in their community. MEASUREMENTS: Individual in-depth interviews were conducted and transcribed verbatim. Transcripts were analyzed according to thematic derivation procedures. RESULTS: The themes that emerged from the interviews with the PHNs included: (a) components of the CBT training program that nurses most valued, (b) benefits of training for their professional role as a PHN, (c) implications for practice, and (d) using CBT skills in their personal lives. CONCLUSIONS: The provision of CBT training to PHNs may not only positively impact their work with clients with mental illness, but may also have the potential to provide broader clinical and professional benefits for these skilled professionals and their other clients.

Public health nurse delivered group cognitive behavioral therapy (CBT) for postpartum depression: A pilot study.

OBJECTIVES: Although postpartum depression (PPD) affects 1 in 5 women, just 15% receive treatment. Cognitive Behavioural Therapy (CBT) is a first-line treatment for PPD. The objective of this pilot study was to determine the feasibility and acceptability of public health nurse (PHN)-delivered group CBT for PPD and to determine preliminary estimates of effect. DESIGN: A pre-posttest design was used. Participants provided data before and after the CBT groups. SAMPLE: Seven women who were over the age of 18 and had given birth in the past year participated. MEASUREMENTS: Feasibility and acceptability focused on PHN training, recruitment, retention, and adherence to the intervention. Participants provided data on depression, worry, health care utilization and mother-infant relations. Women and their partners reported on infant temperament. INTERVENTION: Participants attended a 9-week CBT group delivered by two PHNs. RESULTS: The PHN training, CBT intervention and our study protocol were found to be feasible and acceptable to participants. Reductions were seen in depression and worry. The number of health care visits decreased; mother-infant relations improved. CONCLUSIONS: These findings highlight the feasibility of PHN-delivered group CBT for PPD and suggest that it could reduce the burden of PPD on women and their children.

Actomyosin dynamics drive local membrane component organization in an in vitro active composite layer.

The surface of a living cell provides a platform for receptor signaling, protein sorting, transport, and endocytosis, whose regulation requires the local control of membrane organization. Previous work has revealed a role for dynamic actomyosin in membrane protein and lipid organization, suggesting that the cell surface behaves as an active composite composed of a fluid bilayer and a thin film of active actomyosin. We reconstitute an analogous system in vitro that consists of a fluid lipid bilayer coupled via membrane-associated actin-binding proteins to dynamic actin filaments and myosin motors. Upon complete consumption of ATP, this system settles into distinct phases of actin organization, namely bundled filaments, linked apolar asters, and a lattice of polar asters. These depend on actin concentration, filament length, and actin/myosin ratio. During formation of the polar aster phase, advection of the self-organizing actomyosin network drives transient clustering of actin-associated membrane components. Regeneration of ATP supports a constitutively remodeling actomyosin state, which in turn drives active fluctuations of coupled membrane components, resembling those observed at the cell surface. In a multicomponent membrane bilayer, this remodeling actomyosin layer contributes to changes in the extent and dynamics of phase-segregating domains. These results show how local membrane composition can be driven by active processes arising from actomyosin, highlighting the fundamental basis of the active composite model of the cell surface, and indicate its relevance to the study of membrane organization.

MaxSynBio: Avenues Towards Creating Cells from the Bottom Up.

A large German research consortium mainly within the Max Planck Society ("MaxSynBio") was formed to investigate living systems from a fundamental perspective. The research program of MaxSynBio relies solely on the bottom-up approach to synthetic biology. MaxSynBio focuses on the detailed analysis and understanding of essential processes of life through modular reconstitution in minimal synthetic systems. The ultimate goal is to construct a basic living unit entirely from non-living components. The fundamental insights gained from the activities in MaxSynBio could eventually be utilized for establishing a new generation of biotechnological processes, which would be based on synthetic cell constructs that replace the natural cells currently used in conventional biotechnology.

Mindfulness-based cognitive therapy as an augmentation treatment for obsessive-compulsive disorder.

A significant number of obsessive-compulsive disorder (OCD) patients continue to experience symptoms that interfere with their functioning following cognitive behavioural therapy (CBT). Providing an additional augmentation treatment following CBT could help reduce these residual symptoms. Mindfulness interventions that facilitate less reactivity to thoughts and feelings may be helpful for patients suffering from residual OCD symptoms. The purpose of the current randomized waitlist control trial was to evaluate the feasibility and impact of providing an 8-week mindfulness-based cognitive therapy (MBCT) intervention following completion of a CBT intervention to OCD patients who continued to suffer from significant symptoms. Results indicated that compared to the waitlist control group, MBCT participants reported decreases in OCD symptoms (d = 1.38), depression symptoms (d = 1.25), anxiety symptoms (d = 1.02), and obsessive beliefs (d = 1.20) along with increases in self-compassion (d = 0.77) and mindfulness skills (d = 0.77). Additionally, participants reported high levels of satisfaction with the MBCT intervention. The results suggest that the use of MBCT for OCD as an augmentation therapy is acceptable to patients who continue to suffer from OCD symptoms after completing CBT and provides some additional relief from residual symptoms. KEY PRACTITIONER MESSAGE: Mindfulness interventions teach skills that facilitate disengaging from cognitive routines and accepting internal experience, and these skills may be valuable in treating obsessive-compulsive disorder (OCD), as individuals describe getting "stuck" in repetitive thoughts and consequent rituals. The results of this study suggest that teaching mindfulness skills using an 8-week mindfulness-based cognitive therapy (MBCT) intervention provides an added benefit (decreases in OCD, depression, and anxiety symptoms) for patients with OCD who have completed a cognitive behavioural therapy intervention and continued to suffer from significant symptoms. Participation in MBCT was also associated with increases in mindfulness skills including increased ability to be nonjudgmental and nonreactive. By fostering a nonjudgmental stance towards intrusive thoughts, mindfulness may discourage suppression and avoidance of thoughts and this could lead to increased habituation and a decreased reliance on compulsions. The use of MBCT as an augmentation treatment should be further explored to elucidate whether this treatment is beneficial for preventing relapse of OCD and could be compared against further cognitive behavioural therapy to see if offering participants a different and theoretically compelling intervention, such as MBCT, would outperform "more of the same" for individuals with OCD.