Estimating spatio-temporal fields through reinforcement learning.

Prediction and estimation of phenomena of interest in aquatic environments are challenging since they present complex spatio-temporal dynamics. Over the past few decades, advances in machine learning and data processing contributed to ocean exploration and sampling using autonomous robots. In this work, we formulate a reinforcement learning framework to estimate spatio-temporal fields modeled by partial differential equations. The proposed framework addresses problems of the classic methods regarding the sampling process to determine the path to be used by the agent to collect samples. Simulation results demonstrate the applicability of our approach and show that the error at the end of the learning process is close to the expected error given by the fitting process due to added noise.

Towards Energy-Aware Feedback Planning for Long-Range Autonomous Underwater Vehicles.

Ocean ecosystems have spatiotemporal variability and dynamic complexity that require a long-term deployment of an autonomous underwater vehicle for data collection. A new generation of long-range autonomous underwater vehicles (LRAUVs), such as the Slocum glider and Tethys-class AUV, has emerged with high endurance, long-range, and energy-aware capabilities. These new vehicles provide an effective solution to study different oceanic phenomena across multiple spatial and temporal scales. For these vehicles, the ocean environment has forces and moments from changing water currents which are generally on the order of magnitude of the operational vehicle velocity. Therefore, it is not practical to generate a simple trajectory from an initial location to a goal location in an uncertain ocean, as the vehicle can deviate significantly from the prescribed trajectory due to disturbances resulted from water currents. Since state estimation remains challenging in underwater conditions, feedback planning must incorporate state uncertainty that can be framed into a stochastic energy-aware path planning problem. This article presents an energy-aware feedback planning method for an LRAUV utilizing its kinematic model in an underwater environment under motion and sensor uncertainties. Our method uses ocean dynamics from a predictive ocean model to understand the water flow pattern and introduces a goal-constrained belief space to make the feedback plan synthesis computationally tractable. Energy-aware feedback plans for different water current layers are synthesized through sampling and ocean dynamics. The synthesized feedback plans provide strategies for the vehicle that drive it from an environment's initial location toward the goal location. We validate our method through extensive simulations involving the Tethys vehicle's kinematic model and incorporating actual ocean model prediction data.

Experiences in the military may impact dual-axis neuroendocrine processes in veterans.

Military stressors such as survival training can affect endocrine functioning in the short term, and combat has been associated with endocrine changes linked to psychopathology. However, studies with military samples examining whether there are individual differences in these changes as part of normal development, or as an adaptive mechanism in adulthood are lacking. This study examined whether exposure to combat in a sample of veterans was associated with differential endocrine activity to a laboratory frustration task. Results indicated that Army veterans demonstrated significant testosterone reactivity to frustration and negative coupling between cortisol and testosterone. Alternatively, Navy and Marine veterans demonstrated little testosterone reactivity to frustration and positive coupling between cortisol and testosterone. Positive cortisol-testosterone coupling was stronger among individuals who had more dangerous combat experiences. This latter pattern may better prepare individuals for stressful life experiences and supports the contention that adulthood stressors may calibrate endocrine systems. Results are explained in the context of the Adaptive Calibration Model (Ellis et al., 2012, Developmental Psychology, 48(3), 598-623) which proposes that exposure to key environmental dimensions during endocrinologically malleable life stages (e.g., puberty) can change stress responsivity, resulting in a faster life history trajectory (e.g., increased risk-taking and aggression).

Martyrdom redefined: self-destructive killers and vulnerable narcissism.

Lankford shows that suicide terrorists have much in common with maladjusted persons who die by suicide. However, what differentiates suicidal killers from those who "only" commit suicide? A key element may be vulnerable narcissism. Narcissism has been simultaneously linked to interpersonal aggression, achievement, and depression. These traits may explain the paradoxical picture of a person who may appear "normal" in some aspects, and yet hate himself and others so intensely as to seek mutual destruction.

Dopamine receptor (D4) polymorphism is related to comorbidity between marijuana abuse and depression.

The rates of marijuana abuse are steadily increasing in the U.S. Data suggest that comorbid marijuana abuse and depression is associated with worse outcomes than either diagnosis. Genetic studies independently link the DRD4 gene polymorphism to substance use and to internalizing disorders, but no study has examined whether the DRD4 polymorphism is linked to comorbid marijuana use and depression in a population sample. This study examined associations between the DRD4 gene 48bp VNTR polymorphism and comorbidity between marijuana use frequency and depression in a diverse, non-clinical adolescent sample (n=1882; ages 14 to 18) from the National Longitudinal Study of Adolescent Health (Add Health). Multinomial regression analyses indicated that the odds of being comorbid for depressive symptoms and marijuana use are approximately 2.5≥ with the ≥7R/≥7R genotype than youths who carry the <7R/<7R genotype, controlling for the effects of ethnicity, gender, age, violent victimization, and alcohol related problems. Findings provide genetic clues for psychopathology characterized by prominent externalizing and internalizing features.

Pharmacological prevention of combat-related PTSD: a literature review.

Preventing posttraumatic stress disorder (PTSD) could have a significant positive impact on military readiness and quality of life. Few studies have examined whether pharmacological agents may prevent PTSD, and there has not been a systematic and critical review of these studies in order to guide future research efforts. We performed a literature review of articles examining the use of pharmacological agents for the prevention of PTSD. A total of 27 articles met inclusion criteria for the review and their results are summarized. The review points to corticosteroids and propranolol as the most promising agents for future research. Gamma-Amino butyric acid mimetic drugs received the least support. Complementary approaches using psychotherapy and pharmacological agents could also yield good results. Research aimed at determining the potential efficacy of these agents could start being carried out in the field with smaller numbers of personnel that has not been personally injured but have witnessed traumatic events. In addition, psychological interventions immediately after postdeployment could be used in large numbers of soldiers. Preliminary studies regarding the use of pharmacologic agents for the secondary prevention of PTSD are promising. However, much larger studies are needed before implementation in generalized practice.

Screening for disinhibited disorder cases in a college population: Performance of the SMAST, DAST, SCID-II-Q, and PDQ-4.

Psychiatric disorders characterized by disinhibition--substance use disorders, antisocial personality disorder (PD), and borderline PD--represent a serious risk to the safety and health of college students. The ability of researchers and clinicians to identify students most at risk for disinhibited disorders associated with campus crime, violence, and self-harm depends on measures with strong evidence of diagnostic efficiency, yet data on the diagnostic efficiency of screening measures in college populations are lacking. The authors addressed this need by examining the diagnostic efficiency of commonly used screening measures for disinhibited disorders in a sample of 2,085 students, 79 of whom also completed diagnostic interviews. Results suggest that the diagnostic efficiency (e.g., sensitivity, specificity) of screening measures for substance use disorders and antisocial PD in college samples can be increased by making simple adjustments in screening cutoff criteria. Similar adjustments did not increase the diagnostic efficiency of the screening measure for borderline PD, and this suggested that certain screeners may best be aimed at ruling out disorders. This type of information offers users flexibility with which to tailor the screening threshold to serve different objectives.

Relation of physiological reactivity and perceived coping to substance use disorders.

We examined the interaction between a form of subjective emotional reactivity (perceived coping) and physiological reactivity in relation to risk for substance use disorders. Skin conductance responses to unpredictable white noise blasts were collected from 110 men and women who also rated their perceived coping to the blasts and underwent semi-structured interviews to assess psychiatric symptoms. Reported inability to cope in conjunction with low skin conductance reactivity were related to higher symptom counts of alcohol and cannabis use disorders as well as antisocial personality disorder symptoms. The findings highlight the potential importance of the interface between cognitive/emotional and physiological processes as they relate to risk for substance use disorders and perhaps other externalizing disorders.

Social anxiety and problematic cannabis use: evaluating the moderating role of stress reactivity and perceived coping.

Despite epidemiological reports indicating an association between social anxiety disorder (SAD) and cannabis use disorders (CUD), there is a paucity of research exploring the nature of this relationship. The present investigation examined potential moderators of this relationship that are consistent with a tension-reduction model of addiction. Specifically, physiological reactivity to stress and perceived coping with stress were evaluated as moderators of the relation between symptoms of SAD and CUD. Physiological (SCR) and subjective (perceived coping) responses to unpredictable white noise bursts were collected from non-clinical participants (n=123). Lifetime symptoms of CUD and anxiety disorders were assessed using a structured diagnostic interview. CUD symptomatology was associated with symptoms of SAD but not with symptoms of any other anxiety disorder. Only perceived coping to unpredictable stimuli moderated the relationship between SAD and CUD symptoms. Findings are discussed in the context of tension-reduction models of co-occurring social anxiety and problematic cannabis use.

The Florida State Twin Registry: research aims and design.

Relatively little is known about the relationship of most personality disorders to executive cognitive functioning despite their associations with frontal cortex activity. Research on genetic influence is lacking for most personality disorders, and research on genetic influences associated with executive cognitive functioning is sparse and mixed. The Florida State Twin Registry was created to conduct a pilot twin study aimed at examining genetic influence on personality disorders and executive cognitive functioning. Measures included structured clinical interviews for symptoms and diagnoses of personality disorders (borderline, histrionic, narcissistic, antisocial, obsessive-compulsive, avoidant, and dependent), depression, substance abuse/dependence, anxiety disorders, and eating disorders. The Wisconsin Card Sorting Test and the Stroop Color-Word Test were administered to assess executive cognitive functioning. Self-report questionnaires were included to assess maladaptive personality traits. Data sharing and future directions for growing the Florida State Twin Registry are discussed.

Suicidality in African American men: the roles of southern residence, religiosity, and social support.

The rise in suicide by African Americans in the United States is directly attributable to the dramatic, nearly three-fold increase in suicide rates of African American males. Gibbs (1997) hypothesized high social support, religiosity, and southern residence are protective factors against suicidality for Black people. This hypothesis was tested among 5,125 participants from the National Comorbidity Survey; 299 were African American males. In this study we hypothesized that there would be significantly lower suicidality in the South, and social support and religiosity would mediate this relationship. Our results indicate that Southern region is indeed a significant predictor of suicidal symptoms in African American men, such that suicidal symptoms were lower in the South, but religiosity and social support did not account for this effect. Other potential mediators were also examined.

Hippocampal volume, spectroscopy, cognition, and mood in patients receiving corticosteroid therapy.

BACKGROUND: Hippocampal volume reduction, declarative memory deficits, and cortisol elevations are reported in persons with major depressive disorder; however, data linking cortisol elevations with hippocampal atrophy are lacking. Prescription corticosteroid-treated patients offer an opportunity to examine corticosteroid effects on hippocampal volume and biochemistry and memory in humans. METHODS: Seventeen patients on long-term prescription corticosteroid therapy and 15 controls of similar age, gender, ethnicity, education, height, and medical history were assessed with magnetic resonance imaging and proton magnetic resonance spectroscopy, the Rey Auditory Verbal Learning Test, Stroop Color Word Test and other neurocognitive measures, the Hamilton Rating Scale for Depression, Young Mania Rating Scale, and Brief Psychiatric Rating Scale. RESULTS: Compared with controls, corticosteroid-treated patients had smaller hippocampal volumes and lower N-acetyl aspartate ratios, lower scores on the Rey Auditory Verbal Learning Test and Stroop Color Word Test, and higher Hamilton Rating Scale for Depression and Brief Psychiatric Rating Scale scores. CONCLUSIONS: Patients receiving chronic corticosteroid therapy have smaller hippocampal volumes, lower N-acetyl aspartate ratios, and declarative memory deficits compared with controls. These findings support the idea that corticosteroid exposure appears to be associated with changes in hippocampal volume and functioning in humans.

Genetic and environmental influences on psychopathy trait dimensions in a community sample of male twins.

Psychopathy appears to be comprised of two broad dimensions: impulsivity/antisocial behavior and interpersonal detachment/callousness. This study examined the extent to which variance in these 2 psychopathy trait dimensions was associated with common or unique genetic, shared, and nonshared environmental factors in two independent samples of reared together 16-18-year-old male twins. One sample included 142 monozygotic (MZ) and 70 dizygotic (DZ) pairs; the other sample included 128 MZ and 58 DZ pairs. Boys completed the Minnesota Temperament Inventory (MTI), a 19-item measure that contains separate subscales: Antisocial and Detachment. Variance in the Antisocial and Detachment scales was associated with additive genetic factors and neither scale was associated with shared environmental factors. As expected, the bivariate biometric analysis suggested genetic influence on the covariance of the scales. The results are consistent with theoretical models of psychopathy that posit some independence in the etiology of the two major trait dimensions of psychopathy.

Open-label nefazodone in patients with a major depressive episode and alcohol dependence.

PURPOSE: Major depressive disorder (MDD) and alcohol dependence (AD) frequently occur together. However, MDD clinical trials generally exclude patients with alcohol-related disorders. GENERAL METHODS: A 12-week, open-label trial of nefazodone in a group of people (n=13) with both a current major depressive episode and current AD was conducted to examine the effect of this antidepressant on depressive symptoms, alcohol use, and cognition. FINDINGS: Scores on the Hamilton Rating Scale for Depression (HRSD) and Hamilton Rating Scale for Anxiety (HRSA) significantly decreased from baseline to exit. In addition, significant reduction in alcohol craving, drinks/week, and days of alcohol use/week was found. Scores on the Rey Auditory Verbal Learning Test (RAVLT) did not significantly improve during the study. Changes in mood/anxiety and memory did not correlate with changes in alcohol use. CONCLUSIONS: Thus, nefazodone therapy was associated with improvement in mood/anxiety and alcohol use, which seem to be independent of each other in this patient sample. However, declarative memory, which was low average at baseline, did not show statistically significant improvement during the 12 weeks of the study.

Effect of lamotrigine on mood and cognition in patients receiving chronic exogenous corticosteroids.

Mood changes, cognitive deficits, and psychosis have been reported during corticosteroid therapy. However, minimal data are available on the treatment of these side effects. This pilot study examined the effect of 12 weeks of open-label lamotrigine treatment (dose: mean=340 mg/day, SD=65) on mood and cognition in five patients receiving prescription corticosteroids continuously for at least 6 months before study entry. The participants showed significant improvement in cognition with lamotrigine. Two subjects who met criteria for a current major depressive episode at baseline had baseline-to-exit reductions in scores on the Hamilton Depression Rating Scale of more than 20 points. These pilot data suggest that lamotrigine may be associated with improved mood and performance on cognitive tasks in steroid-treated patients. Larger controlled trials are needed to confirm these preliminary findings.

Lamotrigine in patients with bipolar disorder and cocaine dependence.

BACKGROUND: Bipolar disorder is associated with the highest substance abuse rates of any psychiatric illness. Therefore, treatments that stabilize mood and decrease drug use or cravings are of great interest. Open-label lamotrigine was examined in 30 outpatients with DSM-IV bipolar disorder and cocaine dependence. Lamotrigine was either added to existing medication regimens or used as monotherapy. METHOD: Lamotrigine was started at a dose of 25 mg/day (12.5 mg/day in those taking valproic acid) and titrated to a maximum dose of 300 mg/day. Subjects received a baseline evaluation including a structured clinical interview and weekly assessments for 12 weeks with the Hamilton Rating Scale for Depression (HAM-D), Young Mania Rating Scale (YMRS), Brief Psychiatric Rating Scale (BPRS), and Cocaine Craving Questionnaire (CCQ). At each appointment, a urine sample was obtained, and participants reported drug use during the previous week. The subjects consisted of 13 men and 17 women with cocaine dependence and bipolar I disorder (N = 22), bipolar II disorder (N = 7), or bipolar disorder not otherwise specified (N = 1), with a mean +/- SD age of 35.4 +/- 7.2 years. Data were analyzed using the last observation carried forward on all subjects who completed the baseline evaluation and at least 1 postbaseline assessment. RESULTS: Significant improvement was observed in HAM-D, YMRS, and BPRS scores (p < or =.02). Cravings also significantly decreased as measured by the CCQ (p <.001). Dollar amount spent on drugs decreased nonsignificantly. Lamotrigine was well tolerated, with no subjects discontinuing due to side effects. CONCLUSION: Lamotrigine treatment was well tolerated in this sample and associated with statistically significant improvement in mood and drug cravings but not drug use. The findings suggest that larger controlled trials of lamotrigine are needed in this population.

Quetiapine in bipolar disorder and cocaine dependence.

OBJECTIVE: Bipolar disorder is associated with the highest rates of substance abuse of any psychiatric illness. Therefore, treatments that stabilize mood and decrease drug use or cravings are of great interest. Atypical antipsychotics are in widespread use in patients with bipolar disorder. However, minimal data are available on their use in bipolar patients with comorbid substance abuse. METHODS: Open-label, add-on, quetiapine therapy was examined for 12 weeks in 17 outpatients with bipolar disorder and cocaine dependence. Subjects were evaluated with a structured clinical interview; Hamilton Depression Rating (HDRS), Young Mania Rating (YMRS), Brief Psychiatric Rating (BPRS) scales; and Cocaine Craving Questionnaire (CCQ). Urine samples and self-reported drug use were also obtained. Data were analyzed using a last observation carried forward method on all subjects given medication at baseline. RESULTS: Significant improvement from baseline to exit was observed in HDRS, YMRS, BPRS and CCQ scores (p < or = 0.05). Dollars spent on cocaine and days/week of cocaine use decreased non-significantly, and urine drug screens did not change significantly from baseline to exit. Quetiapine was well tolerated, with no subjects to our knowledge discontinuing because of side-effects. CONCLUSIONS: The use of quetiapine was associated with substantial improvement in psychiatric symptoms and cocaine cravings. The findings are promising and suggest larger controlled trials of quetiapine are needed in this population.