Is (poly-) substance use associated with impaired inhibitory control? A mega-analysis controlling for confounders.

Many studies have reported that heavy substance use is associated with impaired response inhibition. Studies typically focused on associations with a single substance, while polysubstance use is common. Further, most studies compared heavy users with light/non-users, though substance use occurs along a continuum. The current mega-analysis accounted for these issues by aggregating individual data from 43 studies (3610 adult participants) that used the Go/No-Go (GNG) or Stop-signal task (SST) to assess inhibition among mostly "recreational" substance users (i.e., the rate of substance use disorders was low). Main and interaction effects of substance use, demographics, and task-characteristics were entered in a linear mixed model. Contrary to many studies and reviews in the field, we found that only lifetime cannabis use was associated with impaired response inhibition in the SST. An interaction effect was also observed: the relationship between tobacco use and response inhibition (in the SST) differed between cannabis users and non-users, with a negative association between tobacco use and inhibition in the cannabis non-users. In addition, participants' age, education level, and some task characteristics influenced inhibition outcomes. Overall, we found limited support for impaired inhibition among substance users when controlling for demographics and task-characteristics.

Patterns and predictors of family environment among adolescents at high and low risk for familial bipolar disorder.

Children's perceptions are important to understanding family environment in the bipolar disorder (BD) high-risk context. Our objectives were to empirically derive patterns of offspring-perceived family environment, and to test the association of family environment with maternal or paternal BD accounting for offspring BD and demographic characteristics. Participants aged 12-21 years (266 offspring of a parent with BD, 175 offspring of a parent with no psychiatric history) were recruited in the US and Australia. We modeled family environment using latent profile analysis based on offspring reports on the Conflict Behavior Questionnaire, Family Adaptability and Cohesion Evaluation Scales, and Home Environment Interview for Children. Parent diagnoses were based on the Diagnostic Interview for Genetic Studies and offspring diagnoses were based on the Schedule for Affective Disorders and Schizophrenia for School-Aged Children. Latent class regression was used to test associations of diagnosis and family environment. Two-thirds of all offspring perceived well-functioning family environment, characterized by nurturance, flexibility, and low conflict. Two 'conflict classes' perceived family environments low in flexibility and cohesion, with substantial separation based on high conflict with the father (High Paternal Conflict), or very high conflict and rigidity and low warmth with the mother (High Maternal Conflict). Maternal BD was associated with offspring perceiving High Maternal Conflict (OR 2.8, p = 0.025). Clinical care and psychosocial supports for mothers with BD should address family functioning, with attention to offspring perceptions of their wellbeing. More research is needed on the effect of paternal BD on offspring and family dynamics.

Salivary melatonin onset in youth at familial risk for bipolar disorder.

Melatonin secretion and polysomnography (PSG) were compared among a group of healthy adolescents who were at high familial risk for bipolar disorder (HR) and a second group at low familial risk (LR). Adolescent participants (n = 12) were a mean age 14 ± 2.3 years and included 8 females and 4 males. Saliva samples were collected under standardized condition light (red light) and following a 200 lux light exposure over two consecutive nights in a sleep laboratory. Red Light Melatonin onset (RLMO) was defined as saliva melatonin level exceeding the mean of the first 3 readings plus 2 standard deviations. Polysomnography was also completed during each night. HR youth, relative to LR, experienced a significantly earlier melatonin onset following 200 lux light exposure. Polysomnography revealed that LR youth, relative to HR, spent significantly more time in combined stages 3 and 4 (deep sleep) following red light exposure. Additionally, regardless of the group status (HR or LR), there was no significant difference in Red Light Melatonin Onset recorded at home or in the laboratory, implying its feasibility and reliability.

Traumatic Stress Interacts With Bipolar Disorder Genetic Risk to Increase Risk for Suicide Attempts.

OBJECTIVE: Bipolar disorder (BD) is one of the most heritable psychiatric conditions and is associated with high suicide risk. To explore the reasons for this link, this study examined the interaction between traumatic stress and BD polygenic risk score in relation to suicidal ideation, suicide attempt, and nonsuicidal self-injury (NSSI) in adolescent and young adult offspring and relatives of persons with BD (BD-relatives) compared with adolescent and young adult offspring of individuals without psychiatric disorders (controls). METHOD: Data were collected from 4 sites in the United States and 1 site in Australia from 2006 through 2012. Generalized estimating equation models were used to compare rates of ideation, attempts, and NSSI between BD-relatives (n = 307) and controls (n = 166) and to determine the contribution of demographic factors, traumatic stress exposure, lifetime mood or substance (alcohol/drug) use disorders, and BD polygenic risk score. RESULTS: After adjusting for demographic characteristics and mood and substance use disorders, BD-relatives were at increased risk for suicidal ideation and attempts but not for NSSI. Independent of BD-relative versus control status, demographic factors, or mood and substance use disorders, exposure to trauma within the past year (including bullying, sexual abuse, and domestic violence) was associated with suicide attempts (p = .014), and BD polygenic risk score was marginally associated with attempts (p = .061). Importantly, the interaction between BD polygenic risk score and traumatic event exposures was significantly associated with attempts, independent of demographics, relative versus control status, and mood and substance use disorders (p = .041). CONCLUSION: BD-relatives are at increased risk for suicide attempts and ideation, especially if they are exposed to trauma and have evidence of increased genetic vulnerability.

Substance use disorders in adolescent and young adult relatives of probands with bipolar disorder: What drives the increased risk?

BACKGROUND: Adults with bipolar disorder (BD) have higher rates of substance use disorders (SUDs) compared to the general population. SUD rates in young offspring/relatives of BD probands, as well as factors which drive those rates, are not as well-characterized. METHODS: We aimed to examine SUD prevalence among adolescent/young adult offspring and relatives of probands with and without BD. Data were collected from five sites in the US and Australia during 2006-2011. Youth offspring/relatives ("Relatives of BD probands;" n=267; mean age=16.8years; ±2.9S.D.), identified through a proband family member with DSM-IV BD (Type I or II), were compared to offspring/relatives of control probands ("relatives of control probands;" n=149; mean age=17.4years; ±2.9S.D.). Logistic regression with generalized estimating equations was used to compare the groups across a range of substance use and SUD variables. Odds ratios were calculated for lifetime prevalence of substance outcomes. RESULTS: Bivariate analyses showed DSM-IV SUDs were more prevalent among relatives of BD probands than among relatives of control probands (29% vs. 18%; p=0.01). Generalized estimating equation models showed BD mood and childhood-onset externalizing disorders in adolescent and young adult relatives to each significantly increase the odds (OR=2.80-3.17; p<0.02) for the development of several substance variables among all relatives, whereas the risk of SUDs in relatives was not increased when the relatives had no mood or externalizing disorders themselves. CONCLUSION: Relatives of BD probands with lifetime mood and externalizing disorders report more substance use/SUDs than relatives of control probands. In contrast, SUD outcomes in relatives of BD probands without mood or externalizing disorders were no different from control relatives without psychopathology. Early recognition and treatment of psychiatric disorders may lead to less substance use in this highly vulnerable population.

Neural mechanisms underlying ecstasy-related attentional bias.

Conditioned responses to cues associated with drug taking play a pivotal role in a number of theories of drug addiction. This study examined whether attentional biases towards drug-related cues exist in recreational drug users who predominantly used ecstasy (3,4-methylenedioxymethamphetamine). Experiment 1 compared 30 ecstasy users, 25 cannabis users, and 30 controls in an attentional distraction task in which neutral, evocative, and ecstasy-related pictures were presented within a coloured border, requiring participants to respond as quickly as possible to the border colour. Experiment 2 employed functional magnetic resonance imaging (fMRI) and the attentional distraction task and tested 20 ecstasy users and 20 controls. Experiment 1 revealed significant response speed interference by the ecstasy-related pictures in the ecstasy users only. Experiment 2 revealed increased prefrontal and occipital activity in ecstasy users in all conditions. Activations in response to the ecstasy stimuli in these regions showed an apparent antagonism whereby ecstasy users, relative to controls, showed increased occipital but decreased right prefrontal activation. These results are interpreted to reflect increased visual processing of, and decreased prefrontal control over, the irrelevant but salient ecstasy-related stimuli. These results suggest that right inferior frontal cortex may play an important role in controlling drug-related attentional biases and may thus play an important role in mediating control over drug usage.

Evidence of increased activation underlying cognitive control in ecstasy and cannabis users.

Evidence suggests that users of ecstasy (3,4-methylenedioxymethamphetamine) have behavioural and cognitive deficits and show increased impulsivity. Impulse control impairments have been shown to be common to a number of addictive behaviours and may constitute a risk factor for drug abuse and dependence. The aim of this study was to investigate brain activation during response inhibition and performance monitoring in current recreational drug users who predominantly used ecstasy. Twenty drug users (ten female) and twenty healthy controls were scanned during performance of a response-inhibition GO/NOGO task using functional magnetic resonance imaging. No performance deficits were evident. However, the drug user group revealed elevated frontal and parietal BOLD response during successful inhibitions, and temporal, frontal, and cingulate hyperactivity during commission errors. In addition, the users showed reduced deactivation in the default-mode network during task performance. Whether contributing to or arising from drug use, these results reveal dysregulation in brain regions subserving cognitive control and default-mode processes in current recreational drug users mirroring effects previously observed for "harder" drugs of abuse.

Learning and memory deficits in ecstasy users and their neural correlates during a face-learning task.

It has been consistently shown that ecstasy users display impairments in learning and memory performance. In addition, working memory processing in ecstasy users has been shown to be associated with neural alterations in hippocampal and/or cortical regions as measured by functional magnetic resonance imaging (fMRI). Using functional imaging and a face-learning task, we investigated neural correlates of encoding and recalling face-name associations in 20 recreational drug users whose predominant drug use was ecstasy and 20 controls. To address the potential confounding effects of the cannabis use of the ecstasy using group, a second analysis included 14 previously tested cannabis users (Nestor, L., Roberts, G., Garavan, H., Hester, R., 2008. Deficits in learning and memory: parahippocampal hyperactivity and frontocortical hypoactivity in cannabis users. Neuroimage 40, 1328-1339). Ecstasy users performed significantly worse in learning and memory compared to controls and cannabis users. A conjunction analysis of the encode and recall phases of the task revealed ecstasy-specific hyperactivity in bilateral frontal regions, left temporal, right parietal, bilateral temporal, and bilateral occipital brain regions. Ecstasy-specific hypoactivity was evident in the right dorsal anterior cingulated cortex (ACC) and left posterior cingulated cortex. In both ecstasy and cannabis groups brain activation was decreased in the right medial frontal gyrus, left parahippocampal gyrus, left dorsal cingulate gyrus, and left caudate. These results elucidated ecstasy-related deficits, only some of which might be attributed to cannabis use. These ecstasy-specific effects may be related to the vulnerability of isocortical and allocortical regions to the neurotoxic effects of ecstasy.

Menstrual cycle phase modulates cognitive control over male but not female stimuli.

Evolutionary selection pressures have been one of the factors proposed to underlie sex differences in inhibitory control. Consequently, inhibitory control may vary as a function of the menstrual cycle and may be modulated by the stimuli being processed if these stimuli are related to reproductive success. We used functional MRI to study women's brain activation across the menstrual cycle on a GO/NOGO response inhibition task using attractive male and female faces as stimuli. We detected brain activity changes for both successful inhibitions and errors of commission that were unique to the male stimuli during the follicular phase of the menstrual cycle. That is, when pregnancy was possible women had superior inhibitory brain function and heightened detection of inhibitory failures when processing male stimuli. Moreover, we show that individual differences between females in sexual desire and social risk taking negatively correlate with error-related brain activity to the male stimuli during the follicular phase of the menstrual cycle. These results suggest an interaction between hormonal influences and stimulus-specific effects in producing an endophenotypic outcome predicted by evolutionary psychology, and suggest that the functioning of the brain's monitoring system can predict individual differences in both traits and real-world risk-taking behaviours.