Associations between somatomotor-putamen resting state connectivity and obsessive-compulsive symptoms vary as a function of stress during early adolescence: Data from the ABCD study

Obsessive-compulsive symptoms (OCS) are relatively common during adolescence although most individuals do not meet diagnostic criteria for obsessive-compulsive disorder (OCD). Nonetheless, OCS during adolescence are associated with comorbid psychopathologies and behavioral problems. Heightened levels of environmental stress and greater functional connectivity between the somatomotor network and putamen have been previously associated with elevated OCS in OCD patients relative to healthy controls. However, the interaction of these factors within the same sample of individuals has been understudied. This study examined somatomotor-putamen resting state connectivity, stress, and their interaction on OCS in adolescents from 9-12 years of age. Participants (n = 6386) were drawn from the ABCD Study 4.0 release. Multilevel modeling was used to account for nesting in the data and to assess changes in OCS in this age range. Stress moderated the association between somatomotor-putamen connectivity and OCS (β = 0.35, S.E. = 0.13, p = 0.006). Participants who reported more stress than their average and had greater somatomotor-left putamen connectivity reported more OCS, whereas participants who reported less stress than their average and had greater somatomotor-left putamen connectivity reported less OCS. These data suggest that stress differentially affects the direction of association between somatomotor-putamen connectivity and OCS. Individual differences in the experience or perception of stress may contribute to more OCS in adolescents with greater somatomotor-putamen connectivity.

Prefrontal cortical response to natural rewards and self-reported anhedonia are associated with greater craving among recently withdrawn patients in residential treatment for opioid use disorder

Both anhedonia and craving are common among patients with opioid use disorder (OUD), and are associated with vulnerability to relapse. Although these constructs are theoretically linked relatively few studies have examined them together. In the current study, recently withdrawn patients (N = 71) in residential treatment for prescription OUD underwent a cue reactivity paradigm while being monitored with functional near-infrared spectroscopy (fNIRS). Patients also self-reported symptoms of anhedonia via the Snaith-Hamilton Pleasure Scale (SHAPS), while smartphone-based ecological momentary assessments (EMA) were used to measure craving levels. On average, lower right prefrontal cortex (PFC) activity in response to positive social stimuli was associated with higher craving (β = - 2.87; S.E. = 1.23; p = 0.02). Self-reported anhedonia moderated the association between PFC activity and craving (β = - 1.02; S.E. = 0.48; p = 0.04), such that patients with two or more anhedonic symptoms had a significant and stronger negative association between PFC activation to hedonically positive images and craving, compared to patients with fewer than two anhedonic symptoms, among whom the association was not significant. This finding provides evidence that higher levels of anhedonia among patients in residential treatment for OUD are associated with a stronger link between lower PFC response to positive social experiences and higher levels of craving, potentially increasing overall vulnerability to relapse.

Effective Connectivity during an Avoidance-Based Pavlovian-to-Instrumental Transfer Task

Pavlovian-to-instrumental transfer (PIT) refers to a phenomenon whereby a classically conditioned stimulus (CS) impacts the motivational salience of instrumental behavior. We examined behavioral response patterns and functional magnetic resonance imaging (fMRI) based effective connectivity during an avoidance-based PIT task. Eleven participants (8 females; Mage = 28.2, SD = 2.8, range = 25-32 years) completed the task. Effective connectivity between a priori brain regions engaged during the task was determined using hemodynamic response function group iterative multiple model estimation (HRF-GIMME). Participants exhibited behavior that was suggestive of specific PIT, a CS previously associated with a reinforcing outcome increased instrumental responding directed at the same outcome. We did not find evidence for general PIT; a CS did not significantly increase instrumental responding towards a different but related outcome. Using HRF-GIMME, we recovered effective connectivity maps among corticostriatal circuits engaged during the task. Group-level paths revealed directional effects from left putamen to right insula and from right putamen to right cingulate. Importantly, a direct effect of specific PIT stimuli on blood-oxygen-level-dependent (BOLD) activity in the left putamen was found. Results provide initial evidence of effective connectivity in key brain regions in an avoidance-based PIT task network. This study adds to the literature studying PIT effects in humans and employing GIMME models to understand how psychological phenomena are supported in the brain.

Fox squirrels match food assessment and cache effort to value and scarcity

Scatter hoarders must allocate time to assess items for caching, and to carry and bury each cache. Such decisions should be driven by economic variables, such as the value of the individual food items, the scarcity of these items, competition for food items and risk of pilferage by conspecifics. The fox squirrel, an obligate scatter-hoarder, assesses cacheable food items using two overt movements, head flicks and paw manipulations. These behaviors allow an examination of squirrel decision processes when storing food for winter survival. We measured wild squirrels' time allocations and frequencies of assessment and investment behaviors during periods of food scarcity (summer) and abundance (fall), giving the squirrels a series of 15 items (alternating five hazelnuts and five peanuts). Assessment and investment per cache increased when resource value was higher (hazelnuts) or resources were scarcer (summer), but decreased as scarcity declined (end of sessions). This is the first study to show that assessment behaviors change in response to factors that indicate daily and seasonal resource abundance, and that these factors may interact in complex ways to affect food storing decisions. Food-storing tree squirrels may be a useful and important model species to understand the complex economic decisions made under natural conditions.

The value of high adherence to tamoxifen in women with breast cancer: a community-based cohort study

BACKGROUND

Low adherence to adjuvant tamoxifen is associated with worse health outcomes but little is known about the cost-effectiveness of high adherence.

METHODS

We conducted an economic evaluation using data for all women with incident breast cancer between 1993 and 2000 who were subsequently prescribed tamoxifen in the Tayside region of Scotland. Patient-level, lifetime Markov models evaluated the impact of high vs low adherence to tamoxifen using linked prescribing, cancer registry, clinical cancer audit, hospital discharge and death records. Direct medical costs were estimated for each patient and quality-of-life weights were assigned. Recurrence information was collected by case note review and adherence calculated from prescribing records with low adherence classed below 80%.

RESULTS

A total of 354 (28%) patients had a recorded recurrence and 504 (39%) died. Four hundred and seventy-five (38%) patients had low adherence over the treatment period, which was associated with reduced time to recurrence of 52% (P<0.001). Time to other cause mortality was also reduced by 23% (P=0.055) but this was not statistically significant. For an average patient over her lifetime, low adherence was associated with a loss of 1.43 (95% CI: 1.15-1.71) discounted life years or 1.12 (95% CI: 0.91-1.34) discounted quality-adjusted life years (QALYs) and increased discounted medical costs of £5970 (95% CI: £4644-£7372). Assuming a willingness to pay threshold of £25,000 per QALY, the expected value of changing a patient from low to high adherence is £33,897 (95% CI: £28,322-£39,652).

CONCLUSION

Patients with low adherence have shorter time to recurrence, increased medical costs and worse quality of life. Interventions that encourage patients to continue taking their treatment on a daily basis for the recommended 5-year period may be highly cost-effective.

The value of high adherence to tamoxifen in women with breast cancer: a community-based cohort study

Background:

Low adherence to adjuvant tamoxifen is associated with worse health outcomes but little is known about the cost-effectiveness of high adherence.

Methods:

We conducted an economic evaluation using data for all women with incident breast cancer between 1993 and 2000 who were subsequently prescribed tamoxifen in the Tayside region of Scotland. Patient-level, lifetime Markov models evaluated the impact of high vs low adherence to tamoxifen using linked prescribing, cancer registry, clinical cancer audit, hospital discharge and death records. Direct medical costs were estimated for each patient and quality-of-life weights were assigned. Recurrence information was collected by case note review and adherence calculated from prescribing records with low adherence classed below 80%.

Results:

A total of 354 (28%) patients had a recorded recurrence and 504 (39%) died. Four hundred and seventy-five (38%) patients had low adherence over the treatment period, which was associated with reduced time to recurrence of 52% (P<0.001). Time to other cause mortality was also reduced by 23% (P=0.055) but this was not statistically significant. For an average patient over her lifetime, low adherence was associated with a loss of 1.43 (95% CI: 1.15–1.71) discounted life years or 1.12 (95% CI: 0.91–1.34) discounted quality-adjusted life years (QALYs) and increased discounted medical costs of £5970 (95% CI: £4644–£7372). Assuming a willingness to pay threshold of £25 000 per QALY, the expected value of changing a patient from low to high adherence is £33 897 (95% CI: £28 322–£39 652).

Conclusion:

Patients with low adherence have shorter time to recurrence, increased medical costs and worse quality of life. Interventions that encourage patients to continue taking their treatment on a daily basis for the recommended 5-year period may be highly cost-effective.

Mechanism of gastroesophageal reflux in recumbent asymptomatic human subjects

We investigated the mechanism of gastroesophageal reflux (GER) in 10 health volunteer subjects. Continuous recordings of intraluminal esophageal pH and pressure were obtained on two consecutive nights from 6:00 p.m. to 6:30 a.m. in each subject. During each study, the subject remained recumbent, except to eat a standardized meal after 1 h of basal recording. A manometric assembly with seven recording lumens monitored: (a) lower esophageal sphincter (LES) pressure via a sleeve device 6.5 cm in length, (b) esophageal-body motor activity, (c) swallowing activity in the pharynx, and (d) gastric pressure. An electrode 5 cm above the LES recorded esophageal pH. Sleep was monitored by electroencephalogram. All subjects showed wide variations of basal LES pressure. GER was not related to low steady-state basal LES pressure, but rather occurred during transient 5-30 s episodes of inappropriate complete LES relaxation. The inappropriate LES relaxations were usually either spontaneous or immediately followed appropriate sphincter relaxation induced by swallowing. The majority of GER episodes occurred within the first 3 h after eating. During the night LES relaxation and GER occurred only during transient arousals from sleep or when the subjects were fully awake, but not during stable sleep. After GER the esophagus was generally cleared of refluxed acid by primary peristalsis and less frequently by secondary peristalsis. Nonperistaltic contractions were less effective than peristalsis for clearing acid from the esophagus. We conclude that in asymptomatic recumbent subjects GER is related to transient inappropriate LES relaxations rather than to low steady-state basal LES pressure and also, that primary perstalsis is the major mechanism that clears the esophagus of refluxed material.