Reward learning in pediatric depression and anxiety: preliminary findings in a high-risk sample.

BACKGROUND: Reward learning has been postulated as a critical component of hedonic functioning that predicts depression risk. Reward learning deficits have been established in adults with current depressive disorders, but no prior studies have examined the relationship of reward learning and depression in children. The present study investigated reward learning as a function of familial depression risk and current diagnostic status in a pediatric sample. METHOD: The sample included 204 children of parents with a history of depression (n = 86 high-risk offspring) or parents with no history of major mental disorder (n = 118 low-risk offspring). Semistructured clinical interviews were used to establish current mental diagnoses in the children. A modified signal detection task was used for assessing reward learning. We tested whether reward learning was impaired in high-risk offspring relative to low-risk offspring. We also tested whether reward learning was impaired in children with current disorders known to blunt hedonic function (depression, social phobia, PTSD, GAD, n = 13) compared to children with no disorders and to a psychiatric comparison group with ADHD. RESULTS: High- and low-risk youth did not differ in reward learning. However, youth with current anhedonic disorders (depression, social phobia, PTSD, GAD) exhibited blunted reward learning relative to nondisordered youth and those with ADHD. CONCLUSIONS: Our results are a first demonstration that reward learning deficits are present among youth with disorders known to blunt anhedonic function and that these deficits have some degree of diagnostic specificity. We advocate for future studies to replicate and extend these preliminary findings.

Respiratory sinus arrhythmia reactivity in current and remitted major depressive disorder.

OBJECTIVE: Low resting respiratory sinus arrhythmia (RSA) levels and blunted RSA reactivity are thought to index impaired emotion regulation capacity. Major depressive disorder (MDD) has been associated with aberrant RSA reactivity and recovery to a speech stressor task relative to healthy controls. Whether impaired RSA functioning reflects aspects of the depressed mood state or a stable vulnerability marker for depression is unknown. METHODS: We compared resting RSA and RSA reactivity between adults with MDD (n = 49), remitted depression (RMD, n = 24), and healthy controls (n = 45). Electrocardiogram data were collected during a resting baseline, a paced-breathing baseline, and two reactivity tasks (speech stressor, cold exposure). RESULTS: A group by time quadratic effect emerged (F(2,109) = 4.36, p = .015) for RSA across phases of the speech stressor (baseline, instruction, preparation, speech, recovery). Follow-up analyses revealed that those with MDD uniquely exhibited blunted RSA reactivity, whereas RMD and controls both exhibited the anticipated task-related vagal withdrawal and posttask recovery. The group by time interaction remained after covariation for age, sex, waist circumference, physical activity, and respiration, but not sleep quality. CONCLUSIONS: These results provide new evidence that aberrant RSA reactivity marks features that track the depressed state, such as poor sleep, rather than a stable trait evident among asymptomatic persons.

Parental depression confers greater prospective depression risk to females than males in emerging adulthood.

Females are at greater risk of depression than males, a pattern arising in adolescence and continuing in adulthood. One hypothesis is that major risk factors operate more robustly for females. We tested whether parental depression history imposes greater prospective depression risk for female emerging adults in a large community sample (ages 18-19, N = 637). Utilizing linear mixed regressions to model symptom changes over 2 years, we found the predictive utility of parental depression varied by gender. Females had higher depression symptoms overall, and those with parental depression remained at high levels throughout the adulthood transition, compared to at-risk males whose elevated symptoms decreased. This effect was specific to offspring depression (versus anxiety) and was found only for parental depression (versus other disorders). Female emerging adults with a parental depression history are at increased risk for future depression symptom elevations, which may partially explain their increased risk for depressive disorders in adulthood.

Poor reported sleep quality predicts low positive affect in daily life among healthy and mood-disordered persons.

Sleep disturbance is a core symptom of mood disorders. However, surprisingly little is known about the relationship between sleep quality and ambulatory daily mood, especially in mood-disordered populations. We assessed ambulatory positive affect (PA) and negative affect (NA) 10 times daily for three consecutive days with the computerized experience sampling method among persons with major depression (n = 35), minor depression (n = 25) and healthy controls (n = 36). Sleep quality was assessed with the Pittsburgh Sleep Quality Index (PSQI). Poorer sleep quality predicted lower ambulatory PA, even after accounting for the effects of diagnostic group and self-reported anxiety. Conversely, sleep quality did not predict ambulatory NA once diagnostic group was accounted for. Analyzes of specific PSQI component scores indicated that poor subjective sleep quality and self-reported daytime dysfunction were the sleep components most strongly tied to reports of low ambulatory PA. Impaired sleep quality may be responsible for reduced pleasurable experience in everyday life.

Does emotion predict the course of major depressive disorder? A review of prospective studies.

PURPOSE: Emotional dysfunction is a hallmark of major depressive disorder (MDD). There has been wide interest in identifying the nature and significance of emotional deficits in MDD. Given the paramount goal of identifying etiological markers of MDD that can sharpen prevention and treatment efforts, researchers have pursued emotion as a functionally significant factor and predictor of clinical course in MDD. This review is the first to summarize the literature examining emotion as a predictor of the clinical course of MDD. METHOD: We conducted a systematic review of all published studies reporting on the prospective relationship between positive and negative emotionality (PE and NE)--measured at the state or trait level--and the longitudinal course of MDD in diagnosed adults. Physiological, behavioural, and subjective indices of emotion were considered. The primary analyses encompassed 28 research reports that included data from 3,798 participants and tested a total of 60 hypotheses. RESULTS: Lower levels of PE predicted poorer MDD course with some consistency. Paradoxically, both lower levels of state NE and higher levels of trait NE predicted poorer MDD course. The relationships between emotionality and MDD course generally held even after initial depression symptom severity was taken into account. CONCLUSION: Emotion shows promise as a predictor of MDD course. Implications of these data for current theories of emotion and MDD, the apparently divergent relation between state and trait NE and course, and future directions to further clarify the functional significance of emotion in the context of MDD are discussed.

A meta-analysis of emotional reactivity in major depressive disorder.

Three alternative views regarding how Major Depressive Disorder (MDD) alters emotional reactivity have been featured in the literature: positive attenuation (reduced positive reactivity), negative potentiation (increased negative reactivity), and emotion context insensitivity (ECI; reduced positive and negative reactivity). Although empirical studies have accumulated on emotional reactivity in MDD, this report is to our knowledge the first systematic quantitative review of this topic area. In omnibus analyses of 19 laboratory studies comparing the emotional reactivity of healthy individuals to that of individuals with MDD, MDD was characterized by reduced emotional reactivity to both positively and negatively valenced stimuli, with the reduction larger for positive stimuli (d=-.53) than for negative stimuli (d=-.25). Results were similar when 3 major emotion response systems (self-reported experience, expressive behavior, and peripheral physiology) were analyzed individually. The ECI view of emotional reactivity in MDD is well supported by laboratory data. Implications for the understanding of emotions in MDD are discussed.

Heightened reward learning under stress in generalized anxiety disorder: a predictor of depression resistance?

Stress-induced anhedonia is associated with depression vulnerability (Bogdan & Pizzagalli, 2006). We investigated stress-induced deficits in reward learning in a depression-vulnerable group with analogue generalized anxiety disorder (GAD, n = 34), and never-depressed healthy controls (n = 41). Utilizing a computerized signal detection task, reward learning was assessed under stressor and neutral conditions. Controls displayed intact reward learning in the neutral condition, and the expected stress-induced blunting. The GAD group as a whole also showed intact reward learning in the neutral condition. When GAD subjects were analyzed as a function of prior depression history, never-depressed GAD subjects showed heightened reward learning in the stressor condition. Better reward learning under stress among GAD subjects predicted lower depression symptoms 1 month later. Robust reward learning under stress may indicate depression resistance among anxious individuals.