Validation of a Multivariable Model to Predict Suicide Attempt in a Mental Health Intake Sample.

Importance: Given that suicide rates have been increasing over the past decade and the demand for mental health care is at an all-time high, targeted prevention efforts are needed to identify individuals seeking to initiate mental health outpatient services who are at high risk for suicide. Suicide prediction models have been developed using outpatient mental health encounters, but their performance among intake appointments has not been directly examined. Objective: To assess the performance of a predictive model of suicide attempts among individuals seeking to initiate an episode of outpatient mental health care. Design, Setting, and Participants: This prognostic study tested the performance of a previously developed machine learning model designed to predict suicide attempts within 90 days of any mental health outpatient visit. All mental health intake appointments scheduled between January 1, 2012, and April 1, 2022, at Kaiser Permanente Northern California, a large integrated health care delivery system serving over 4.5 million patients, were included. Data were extracted and analyzed from August 9, 2022, to July 31, 2023. Main Outcome and Measures: Suicide attempts (including completed suicides) within 90 days of the appointment, determined by diagnostic codes and government databases. All predictors were extracted from electronic health records. Results: The study included 1 623 232 scheduled appointments from 835 616 unique patients. There were 2800 scheduled appointments (0.17%) followed by a suicide attempt within 90 days. The mean (SD) age across appointments was 39.7 (15.8) years, and most appointments were for women (1 103 184 [68.0%]). The model had an area under the receiver operating characteristic curve of 0.77 (95% CI, 0.76-0.78), an area under the precision-recall curve of 0.02 (95% CI, 0.02-0.02), an expected calibration error of 0.0012 (95% CI, 0.0011-0.0013), and sensitivities of 37.2% (95% CI, 35.5%-38.9%) and 18.8% (95% CI, 17.3%-20.2%) at specificities of 95% and 99%, respectively. The 10% of appointments at the highest risk level accounted for 48.8% (95% CI, 47.0%-50.6%) of the appointments followed by a suicide attempt. Conclusions and Relevance: In this prognostic study involving mental health intakes, a previously developed machine learning model of suicide attempts showed good overall classification performance. Implementation research is needed to determine appropriate thresholds and interventions for applying the model in an intake setting to target high-risk cases in a manner that is acceptable to patients and clinicians.

Nonsuicidal self-injury in a college population: general trends and sex differences.

OBJECTIVE: To describe basic nonsuicidal self-injury (NSSI) characteristics and to explore sex differences. METHODS: A random sample from 8 universities were invited to participate in a Web-based survey in 2006-2007; 38.9% (n = 14,372) participated. Analysis assessed sex differences in NSSI prevalence, practices, severity, perceived dependency, and help-seeking; adjusted odds ratios for NSSI characteristics were calculated by sex status. RESULTS: Lifetime NSSI prevalence rates averaged 15.3%. Females were more likely than males to self-injure because they were upset (adjusted odds ratio [AOR] = 1.6; 95% confidence interval [CI] = 1.3-2.1) or in hopes that someone would notice them (AOR = 1.6, 95% CI = 1.1-2.7). Males were 1.6 times (95% CI = 1.2-2.2) more likely to report anger and 4.0 times (95% CI = 2.3-6.8) more likely to report intoxication as an initiating factor. Sexual orientation predicted NSSI, particularly for women (Wald F = 8.81, p ≤ .000). Only 8.9% of the NSSI sample reported disclosing NSSI to a mental health professional. CONCLUSIONS: NSSI is common in college populations but varies significantly by sex and sexual orientation. NSSI disclosure is low among both sexes.

Interactions between myosin and actin crosslinkers control cytokinesis contractility dynamics and mechanics.

INTRODUCTION: Contractile networks are fundamental to many cellular functions, particularly cytokinesis and cell motility. Contractile networks depend on myosin-II mechanochemistry to generate sliding force on the actin polymers. However, to be contractile, the networks must also be crosslinked by crosslinking proteins, and to change the shape of the cell, the network must be linked to the plasma membrane. Discerning how this integrated network operates is essential for understanding cytokinesis contractility and shape control. Here, we analyzed the cytoskeletal network that drives furrow ingression in Dictyostelium. RESULTS: We establish that the actin polymers are assembled into a meshwork and that myosin-II does not assemble into a discrete ring in the Dictyostelium cleavage furrow of adherent cells. We show that myosin-II generates regional mechanics by increasing cleavage furrow stiffness and slows furrow ingression during late cytokinesis as compared to myoII nulls. Actin crosslinkers dynacortin and fimbrin similarly slow furrow ingression and contribute to cell mechanics in a myosin-II-dependent manner. By using FRAP, we show that the actin crosslinkers have slower kinetics in the cleavage furrow cortex than in the pole, that their kinetics differ between wild-type and myoII null cells, and that the protein dynamics of each crosslinker correlate with its impact on cortical mechanics. CONCLUSIONS: These observations suggest that myosin-II along with actin crosslinkers establish local cortical tension and elasticity, allowing for contractility independent of a circumferential cytoskeletal array. Furthermore, myosin-II and actin crosslinkers may influence each other as they modulate the dynamics and mechanics of cell-shape change.

Dictyostelium myosin II mechanochemistry promotes active behavior of the cortex on long time scales.

Cell cortices rearrange dynamically to complete cytokinesis, crawlin response to chemoattractant, build tissues, and make neuronal connections. Highly enriched in the cell cortex, actin, myosin II, and actin crosslinkers facilitate cortical movements. Because cortical behavior is the consequence of nanoscale biochemical events, it is essential to probe the cortex at this level. Here, we use high-resolution laser-based particle tracking to examine how myosin II mechanochemistry and dynacortin-mediated actin crosslinking control cortex dynamics in Dictyostelium. Consistent with its low duty ratio, myosin II does not directly drive active bead motility. Instead, myosin II and dynacortin antagonistically regulate other active processes in the living cortex.

Dynacortin contributes to cortical viscoelasticity and helps define the shape changes of cytokinesis.

During cytokinesis, global and equatorial pathways deform the cell cortex in a stereotypical manner, which leads to daughter cell separation. Equatorial forces are largely generated by myosin-II and the actin crosslinker, cortexillin-I. In contrast, global mechanics are determined by the cortical cytoskeleton, including the actin crosslinker, dynacortin. We used direct morphometric characterization and laser-tracking microrheology to quantify cortical mechanical properties of wild-type and cortexillin-I and dynacortin mutant Dictyostelium cells. Both cortexillin-I and dynacortin influence cytokinesis and interphase cortical viscoelasticity as predicted from genetics and biochemical data using purified dynacortin proteins. Our studies suggest that the regulation of cytokinesis ultimately requires modulation of proteins that control the cortical mechanical properties that establish the force-balance that specifies the shapes of cytokinesis. The combination of genetic, biochemical, and biophysical observations suggests that the cell's cortical mechanical properties control how the cortex is remodeled during cytokinesis.

An open trial of bupropion for the treatment of adults with attention-deficit/hyperactivity disorder and bipolar disorder.

BACKGROUND: Despite the increasing recognition of comorbid attention-deficit/hyperactivity disorder (ADHD) and bipolar disorder (BPD) in adults, there are no prospective trials of pharmacological agents to treat ADHD in these patients. Given the efficacy of bupropion for ADHD in adults, as well as its use in the management of bipolar depression, we studied the tolerability and efficacy of sustained-release (SR) bupropion in adults with ADHD plus BPD. METHODS: This was an open, prospective, 6-week trial of bupropion SR (up to 200 mg b.i.d.) in adults with DSM-IV ADHD plus historical bipolar I disorder (BPD I) (10%) or bipolar II disorder (BPD II) (90%). Adults receiving adjunct antimanic agents (mood stabilizers and antipsychotics) at baseline were included in the study. We used standardized psychiatric instruments for diagnosis and outcome. Efficacy was based primarily on the Clinical Global Impression Scale (CGI) for ADHD and the ADHD symptom checklist. RESULTS: Of 36 patients entered (75% male, mean age 34 years), 30 patients (83%) completed the protocol. At end point (last observation carried forward [LOCF]) compared to baseline, treatment with bupropion SR resulted in significant reductions in the ADHD symptom checklist (-55%, z = 5.63, p <.001) and CGI severity of ADHD (-40%, z = 6.285, p <.001). Bupropion was associated with reductions in ratings of mania and depression. CONCLUSIONS: The results from this open study of adults with ADHD plus BPD suggest that sustained-release bupropion may be effective in treating ADHD in the context of a lifetime diagnosis of BPD, without significant activation of mania. Further controlled trials are warranted.

Dictyostelium cytokinesis: from molecules to mechanics.

Cytokinesis is the mechanical process that allows the simplest unit of life, the cell, to divide, propagating itself. To divide, the cell converts chemical energy into mechanical energy to produce force. This process is thought to be active, due in large part to the mechanochemistry of the myosin-II ATPase. The cell's viscoelasticity defines the context and perhaps the magnitude of the forces that are required for cytokinesis. The viscoelasticity may also guide the force-generating apparatus, specifying the cell shape change that results. Genetic, biochemical, and mechanical measurements are providing a quantitative view of how real proteins control this essential life process.