Drinking alcohol by mid-adolescence is related to reduced reward reactivity: Novel evidence of positive valence system alterations in early initiating female youth.

Initiation of alcohol use at younger ages is prognostic of later drinking problems. Reward system dysfunction is theorized to contribute to early initiation and escalation of drinking, but existing evidence supports both hyposensitivity and hypersensitivity as risk-markers; research employing effective indices of reward processing is needed for clarification. The reward positivity (RewP) is a well-established neurophysiological index of hedonic "liking," an important aspect of reward processing. Adult research has yielded conflicting findings, with different studies reporting reduced, enhanced, or null associations of RewP with engagement in or risk for harmful alcohol use. No study has examined relations between RewP and multiple indices of drinking in youth. Here, we examined how RewP measured in a gain/loss feedback task related to self-reported drinking initiation and past-month drinking, when accounting for age along with depression and externalizing symptoms, in 250 mid-adolescent females. Analyses showed that (1) compared to not-yet drinkers, adolescents endorsing drinking initiation responded less strongly to monetary gain (RewP) but not loss feedback (FN), and (2) past-month drinking was unrelated to both RewP and FN magnitude. These findings provide evidence for reduced hedonic "liking" as a concomitant of early drinking initiation in adolescent females and warrant further research with mixed-sex adolescent samples exhibiting greater drinking variability.

The P300, loneliness, and depression in older adults.

Depression is associated with high levels of cognitive impairment and increased loneliness among older adults. The current study examines associations between a reliable and robust neural marker of cognitive impairment (i.e., the P300 event-related brain potential [ERP]), loneliness, and depression and assesses the role of loneliness in the P300─depression relationship. In a community sample of 70 older adults between 61 and 75 years, we evaluated cross-sectional associations between depressive symptoms (Geriatric Depression Scale), loneliness (NIH Toolbox), and P300 amplitude measured from the electroencephalogram during a go/no-go task. Results indicated that reduced go and no-go P300 amplitudes were associated with increased depressive symptom severity, with the most unique variance accounted for by a reduced no-go P300 amplitude. Notably, loneliness significantly moderated the no-go P300-depressive symptom severity relationship, such that there was no relationship between the no-go P300 and depressive symptom severity among older adults reporting low levels of loneliness. This finding provides insight into the possibility that social support may offer protection against the depressogenic effects of poor inhibitory control in older adults. Taken together, this study provides a novel examination of the relationships between depression, loneliness, and the P300 ERP in older adults, with important implications for understanding the role of neural inhibition and loneliness in relation to depressive symptomatology.

Blunted Flanker P300 Demonstrates Specificity to Depressive Symptoms in Females during Adolescence.

Recent research suggests that depressive disorders in adults are characterized by reductions in flanker P300 amplitude, and that a reduced flanker P300 may also predict worst depressive trajectories over time. The current study extended this work to adolescence-and to evaluate the specificity of the relationship between flanker P300 to depressive symptoms versus anxiety symptoms, and whether the association between flanker P300 and depressive symptoms was moderated by biological sex. To this end, P300 amplitude, depression, anxiety, and sex were assessed in a large sample of 619 adolescents aged 11 to 14. Participants completed a speeded response flanker task while EEG was recorded, as well as self-reported measures of current depression and anxiety symptoms. Reduced P300 amplitude was related to both heightened depression and anxiety symptoms in zero-order correlations. Regression-based analyses suggest that reduced P300 was uniquely related to depressive symptoms. Furthermore, this negative association between P300 and depression was apparent in female adolescents, but not male adolescents. In sum, the current study suggests that flanker P300 amplitude may potentially serve as a neural marker specific to depression in females during adolescence.

Reduced flanker P300 prospectively predicts increases in depression in female adolescents.

Past research has found that P300 is smaller in depressed adults. Research examining P300 in relation to adolescent depression is more inconsistent; most studies fail to find P300 differences between currently depressed adolescents and controls. Previous studies have not examined the potential predictive utility of P300 in regard to adolescent depression. Therefore, the current study investigated the relationship between P300 amplitude and depression symptoms at baseline and two years later in a sample of 199 female adolescents. At baseline, participants completed measures of depression, followed by a speeded response task (flanker) while EEG was recorded. Two years later, participants completed the same depression measures. Reduced baseline P300 predicted increases in depression at two-year follow-up. Baseline P300 related particularly to two-year anhedonia and negative self-esteem symptoms. Our study suggest that reduced P300 amplitude can be utilized as a potential risk marker for adolescents at risk for developing increases in depressive symptoms.

Cross-sectional and prospective associations of P300, RewP, and ADHD symptoms in female adolescents.

Attention-deficit/hyperactivity disorder (ADHD), a neurodevelopmental syndrome characterized by impulsivity and distractibility, has been linked to blunted neural indicators of executive function and motivational processing. In the current study, we examined cross-sectional and prospective associations between P300 to feedback stimuli, the reward positivity (RewP), and interview-based and parent-reported ADHD symptoms in a sample of 300 female adolescents aged 8 to 14 who were re-assessed two years later. Cross-sectional analyses indicated that a smaller P300, but not RewP, was associated with greater interview-based and parent-reported ADHD symptoms. Moreover, both the P300 and RewP predicted interview-based symptom exacerbation among participants with some ADHD symptoms at baseline. These effects were found to be independent, supporting the notion of equifinal neurodevelopmental pathways to ADHD: one related to executive function (P300) and the other to motivational processing (RewP). Our results suggest that incorporating psychophysiological measures into early assessment could be valuable for identifying youths likely to have a persistent course of ADHD.