To date, the genetic and environmental architecture of the dimensions of psychological well-being (PWB) remains unexplored.

PWB of 742 twins aged 23–24 years and enrolled in the Italian Twin Registry was assessed with the three-item version of Ryff's Scales of Psychological Well-Being (SPWB). These scales include items for evaluating the PWB dimensions of self-acceptance, positive relations with others, autonomy, environmental mastery, purpose in life, and personal growth. A twin design was used to obtain correlations in the PWB dimensions for monozygotic (MZ) and dizygotic (DZ) twins and to estimate the contribution of genetic and environmental factors to variation and covariation in the dimensions.

Genetic factors explained moderate to substantial proportions of variance in the six SPWB dimensions, with heritability estimates between 37% and 64%. The estimates of genetic correlations were very high (range 0.77–0.99), indicating that genetic factors that influence the expression of the different dimensions of PWB may be shared to a large extent. Non-shared environmental correlations ranged from substantial to high, with the exception of the correlation between autonomy and the dimensions of purpose in life, self-acceptance and personal growth.

This study presents a twin analysis of PWB measured by the SPWB dimensions; it was found that both genes and non-shared environment play a role in individual differences. The genetic and non-shared environmental correlations between SPWB dimensions suggest that common underlying genetic and non-shared environmental factors influence the expression of the different facets of PWB.

It is well known that the hypothalamic–pituitary–adrenal (HPA) axis is compromised in major depression and bipolar disorder. There is increasing evidence that subtle HPA abnormalities, such as elevated cortisol levels, precede the development of an affective disorder. Interpersonal stress is also associated with the development of affective disorders. The present study sought to determine whether interpersonal chronic and episodic stress moderated the relationship between cortisol levels in the natural environment and risk status, defined as having a parent with bipolar disorder.

Sixty-two offspring of parents with bipolar disorder (OBD) and 60 offspring with no family history of affective disorders (OFH−), aged 19.48 years (s.d.=3.38, range 14–28), completed interviews assessing mental disorders and chronic and episodic stress, and provided saliva samples over 3 days.

Regression analyses revealed that the OBD who experienced high interpersonal chronic stress displayed a larger cortisol rise following awakening than the OBD reporting low interpersonal chronic stress. The same relationship was also found for levels of non-interpersonal chronic stress. The OBD who reported experiencing severe interpersonal episodic stress exhibited higher levels of daytime cortisol than the OBD reporting interpersonal episodic stress of mild severity. Importantly, none of the above relationships were detected in the OFH−. Each of the interactions between family history of affective disorders and stress remained after controlling for age, gender and offspring lifetime affective disorders and current non-affective disorders.

A biological sensitivity to stress may underlie the susceptibility to affective disorders among the OBD.

Twin and sibling studies have identified specific cognitive phenotypes that may mediate the association between genes and the clinical symptoms of attention deficit hyperactivity disorder (ADHD). ADHD is also associated with lower IQ scores. We aimed to investigate whether the familial association between measures of cognitive performance and the clinical diagnosis of ADHD is mediated through shared familial influences with IQ.

Multivariate familial models were run on data from 1265 individuals aged 6–18 years, comprising 920 participants from ADHD sibling pairs and 345 control participants. Cognitive assessments included a four-choice reaction time (RT) task, a go/no-go task, a choice–delay task and an IQ assessment. The analyses focused on the cognitive variables of mean RT (MRT), RT variability (RTV), commission errors (CE), omission errors (OE) and choice impulsivity (CI).

Significant familial association (rF) was confirmed between cognitive performance and both ADHD (rF=0.41–0.71) and IQ (rF=−0.25 to −0.49). The association between ADHD and cognitive performance was largely independent (80–87%) of any contribution from etiological factors shared with IQ. The exception was for CI, where 49% of the overlap could be accounted for by the familial variance underlying IQ.

The aetiological factors underlying lower IQ in ADHD seem to be distinct from those between ADHD and RT/error measures. This suggests that lower IQ does not account for the key cognitive impairments observed in ADHD. The results have implications for molecular genetic studies designed to identify genes involved in ADHD.

Childhood sexual abuse (CSA) has been shown to be a risk factor for personality disorder (PD). However, no previous studies have examined whether associations exist between sexual abuse and abnormal personality as measured both categorically and dimensionally. Such enquiry would more fully illuminate the impact of CSA on adult personality.

Using a large nationally representative sample, we set out to examine associations between CSA and categorically defined PD. We also examined associations between CSA and the five dimensions of personality (openness to experience, conscientiousness, extraversion, agreeableness and neuroticism). A total of 1520 young adults were interviewed to determine the prevalence of sexual abuse occurring before age 16 years. A dimensional measure of personality was completed by 1469 participants, and 1145 had an informant-based PD assessment.

PD was independently associated with repeated CSA [fully adjusted odds ratio (OR) 1.9, 95% confidence interval (CI) 1.1–3.4]. Repeated sexual abuse was also associated with higher neuroticism and lower agreeableness (p values for both <0.001). Adjusting for the effects of potential confounders and mediators, including earlier symptoms of anxiety and depression, had little impact on the strength of associations.

We conclude that repeated CSA is independently associated with categorically defined PD, and also with higher neuroticism and lower agreeableness. Our findings suggest that if a dimensional classification of PDs is adopted in future classification systems, there might be meaningful continuity with previous aetiological research conducted using the current categorical system.

Non-suicidal self-injury (NSSI) has received increased attention in the mental health literature and has been proposed as a diagnostic entity for DSM-5. However, data on NSSI in the United States adult population are lacking.

The prevalence and nature of NSSI were examined in a random-digit dialing sample of 439 adults in the United States. Participants were recruited during July and August of 2008.

Lifetime prevalence of NSSI was 5.9%, including 2.7% who had self-injured five or more times. The 12-month prevalence was 0.9%. Methods of NSSI reported included cutting/carving, burning, biting, scraping/scratching skin, hitting, interfering with wound healing and skin picking. Half of self-injurers reported multiple methods. The average age of onset was 16 years (median 14 years). Instances of NSSI infrequently co-occurred with suicidal thoughts and with use of alcohol or drugs and rarely required medical treatment. Most injurers reported that NSSI functioned to alleviate negative emotions. Fewer reported that they self-injured to punish themselves, to communicate with others/get attention or to escape a situation or responsibility. NSSI was associated with younger age, being unmarried and a history of mental health treatment, but not with gender, ethnicity, educational history or household income.

Results are largely consistent with previous research in adolescent and young adult samples. Study limitations notwithstanding, this study provides the most definitive and detailed information to date regarding the prevalence and characteristics of NSSI in US adults. In the future, it will be important for large-scale epidemiological studies of psychopathology to include questions about NSSI.

The current longitudinal study examined the developmental patterns of marijuana use and their relationship with subsequent psychological adjustment in a community-based sample of urban African American and Puerto Rican women.

Participants were interviewed five times over a period ranging from adolescence (mean age 14.0 years) to adulthood (mean age 32.5 years). Outcome measures included depressive symptoms, anger/hostility and the presence of a substance use disorder (abuse/dependence).

Three distinct trajectories of marijuana use were identified: non-users, increasers and quitters. Increasers reported higher levels of depressive symptoms and anger/hostility than did non-users and were more likely to meet criteria for a substance use disorder at age 32.5 years.

Our findings indicate that early-starting long-term use of marijuana is associated with psychological maladjustment among women. Prevention efforts should emphasize the long-term cost associated with marijuana use, and that the best psychological health is reported by those who abstain from the drug.

Cognitive deficits in alcohol dependence (AD) have been observed, poorer verbal ability being among the most consistent findings. Genetic factors influence both cognitive ability and AD, but whether these influences overlap is not known.

A subset of 602 monozygotic (MZ) and dizygotic (DZ) twins from FinnTwin16, a population-based study of Finnish twins, was used to study the associations of verbal ability with DSM-III-R diagnosis and symptoms of AD, the maximum number of drinks consumed in a 24-h period, and the Rutgers Alcohol Problem Index (RAPI) scores. These twins, most of them selected for within-pair discordance or concordance for their RAPI scores at age 18.5 years, were studied with neuropsychological tests and interviewed with the Semi-Structured Assessment for the Genetics of Alcoholism (SSAGA) in young adulthood (mean age 26.2 years, range 23–30 years).

All alcohol problem measures were associated with lower scores on the Vocabulary subtest of the Wechsler Adult Intelligence Scale – Revised (WAIS-R), a measure of verbal ability. In bivariate genetic models, Vocabulary and the alcohol problem measures had moderate heritabilities (0.54–0.72), and their covariation could be explained by correlated genetic influences (genetic correlations −0.20 to −0.31).

Poorer verbal ability and AD have partly overlapping biological etiology. The genetic and environmental influences on the development of cognitive abilities, alcohol problems and risk factors for AD should be studied further with prospective longitudinal designs.

The methodology commonly used to estimate disease burden, featuring ratings of severity of individual conditions, has been criticized for ignoring co-morbidity. A methodology that addresses this problem is proposed and illustrated here with data from the World Health Organization World Mental Health Surveys. Although the analysis is based on self-reports about one's own conditions in a community survey, the logic applies equally well to analysis of hypothetical vignettes describing co-morbid condition profiles.

Face-to-face interviews in 13 countries (six developing, nine developed; n=31 067; response rate=69.6%) assessed 10 classes of chronic physical and nine of mental conditions. A visual analog scale (VAS) was used to assess overall perceived health. Multiple regression analysis with interactions for co-morbidity was used to estimate associations of conditions with VAS. Simulation was used to estimate condition-specific effects.

The best-fitting model included condition main effects and interactions of types by numbers of conditions. Neurological conditions, insomnia and major depression were rated most severe. Adjustment for co-morbidity reduced condition-specific estimates with substantial between-condition variation (0.24–0.70 ratios of condition-specific estimates with and without adjustment for co-morbidity). The societal-level burden rankings were quite different from the individual-level rankings, with the highest societal-level rankings associated with conditions having high prevalence rather than high individual-level severity.

Plausible estimates of disorder-specific effects on VAS can be obtained using methods that adjust for co-morbidity. These adjustments substantially influence condition-specific ratings.

For the emerging DSM-V, it has been recommended that dimensional and categorical methods be used simultaneously in diagnostic classification; however, little is known about this combined approach for abuse and dependence.

Using data (n=37 708) from the 2007 National Survey on Drug Use and Health (NSDUH), DSM-IV criteria for prescription opioid abuse and dependence among non-prescribed opioid users (n=3037) were examined using factor analysis (FA), latent class analysis (LCA, categorical), item response theory (IRT, dimensional), and factor mixture (hybrid) approaches.

A two-class factor mixture model (FMM) combining features of categorical latent classes and dimensional IRT estimates empirically fitted more parsimoniously to abuse and dependence criteria data than models from FA, LCA and IRT procedures respectively. This mixture model included a severely affected group (7%) with a comparatively moderate to high probability (0.32−0.88) of endorsing all abuse and dependence criteria items, and a less severely affected group (93%) with a low probability (0.003−0.16) of endorsing all criteria. The two empirically defined groups differed significantly in the pattern of non-prescribed opioid use, co-morbid major depression, and substance abuse treatment use.

A factor mixture model integrating categorical and dimensional features of classification fits better to DSM-IV criteria for prescription opioid abuse and dependence in adults than a categorical or dimensional approach. Research is needed to examine the utility of this mixture classification for substance use disorders and treatment response.

To explore the genetic and environmental factors underlying the co-occurrence of lifetime diagnoses of DSM-IV phobia.

Female twins (n=1430) from the population-based Norwegian Institute of Public Health Twin Panel were assessed at personal interview for DSM-IV lifetime specific phobia, social phobia and agoraphobia. Comorbidity between the phobias were assessed by odds ratios (ORs) and polychoric correlations and multivariate twin models were fitted in Mx.

Phenotypic correlations of lifetime phobia diagnoses ranged from 0.55 (agoraphobia and social phobia, OR 10.95) to 0.06 (animal phobia and social phobia, OR 1.21). In the best fitting twin model, which did not include shared environmental factors, heritability estimates for the phobias ranged from 0.43 to 0.63. Comorbidity between the phobias was accounted for by two common liability factors. The first loaded principally on animal phobia and did not influence the complex phobias (agoraphobia and social phobia). The second liability factor strongly influenced the complex phobias, but also loaded weak to moderate on all the other phobias. Blood phobia was mainly influenced by a specific genetic factor, which accounted for 51% of the total and 81% of the genetic variance.

Phobias are highly co-morbid and heritable. Our results suggest that the co-morbidity between phobias is best explained by two distinct liability factors rather than a single factor, as has been assumed in most previous multivariate twin analyses. One of these factors was specific to the simple phobias, while the other was more general. Blood phobia was mainly influenced by disorder specific genetic factors.

The P300 (P3) event-related potential (ERP) component, a possible endophenotype for attention deficit hyperactivity disorder (ADHD), has been widely examined in children, but received little attention in adults. Our objective was to conduct a meta-analysis of P3 studies in adults with ADHD.

We searched the Medline and PsycINFO databases for controlled studies examining both adult ADHD and matched healthy controls. Six relevant publications were identified for the meta-analysis, which had comparable data across studies with regard to the amplitude of ERP components related to target detection (P3, P3b). Pooled effect size (ES) for P3 amplitude as well as the association of the ES with age and gender were investigated using meta-regression.

Comparing the ADHD group versus controls, the pooled effect size for a decrease in P3 amplitude was in the medium range (Cohen's d=−0.55, p=0.0006). Additionally, meta-regression revealed that decrease in P3 amplitude significantly varied with the mean age of ADHD patients (p=0.0087), with a gradual increasing of the difference at higher ages. Results also showed a significant association between the ES and gender, indicating a more pronounced reduction of P3 amplitude in the ADHD group versus controls when females were predominantly represented in the sample.

To our knowledge, this is the first meta-analysis of P3 characteristics in adults with ADHD. It reveals a significantly decreased P3 amplitude during target detection. Our result that the reduction in P3 amplitude increases with age is interpreted in a neurodevelopmental context.

Diagnostic errors can have tremendous consequences because they can result in a fatal chain of wrong decisions. Experts assume that physicians' desire to confirm a preliminary diagnosis while failing to seek contradictory evidence is an important reason for wrong diagnoses. This tendency is called ‘confirmation bias’.

To study whether psychiatrists and medical students are prone to confirmation bias and whether confirmation bias leads to poor diagnostic accuracy in psychiatry, we presented an experimental decision task to 75 psychiatrists and 75 medical students.

A total of 13% of psychiatrists and 25% of students showed confirmation bias when searching for new information after having made a preliminary diagnosis. Participants conducting a confirmatory information search were significantly less likely to make the correct diagnosis compared to participants searching in a disconfirmatory or balanced way [multiple logistic regression: odds ratio (OR) 7.3, 95% confidence interval (CI) 2.53–21.22, p<0.001; OR 3.2, 95% CI 1.23–8.56, p=0.02]. Psychiatrists conducting a confirmatory search made a wrong diagnosis in 70% of the cases compared to 27% or 47% for a disconfirmatory or balanced information search (students: 63, 26 and 27%). Participants choosing the wrong diagnosis also prescribed different treatment options compared with participants choosing the correct diagnosis.

Confirmatory information search harbors the risk of wrong diagnostic decisions. Psychiatrists should be aware of confirmation bias and instructed in techniques to reduce bias.

Longitudinal data from the 1970 British Cohort Study were used to examine the long-term adult outcomes of those who, as children, were placed in public care.

Multivariate logistic estimation models were used to determine whether public care and placement patterns were associated with adult psychosocial outcomes. Seven emotional and behavioural outcomes measured at age 30 years were considered: depression, life dissatisfaction, self-efficacy, alcohol problems, smoking, drug abuse, and criminal convictions.

The analyses revealed a significant association between public care status and adult maladjustment on depression [odds ratio (OR) 1.74], life dissatisfaction (OR 1.45), low self-efficacy (OR 1.95), smoking (OR 1.70) and criminal convictions (OR 2.13).

Overall, the present study findings suggest that there are enduring influences of a childhood admission to public care on emotional and behavioural adjustment from birth to adulthood. Some of the associations with childhood public care were relatively strong, particularly with respect to depression, self-efficacy and criminal convictions.

Previous efforts to derive empirically based eating disorder (ED) typologies through latent structure modeling have been limited by the ethnic and cultural homogeneity of their study populations and their reliance on DSM-IV ED signs and symptoms as indicator variables.

Ethnic Fijian schoolgirls (n=523) responded to a self-report battery assessing ED symptoms, herbal purgative use, co-morbid psychopathology, clinical impairment, cultural orientation, and peer influences. Participants who endorsed self-induced vomiting or herbal purgative use in the past 28 days (n=222) were included in a latent profile analysis (LPA) to identify unique subgroups of bulimic symptomatology.

LPA identified a bulimia nervosa (BN)-like class (n=86) characterized by high rates of binge eating and self-induced vomiting, and a herbal purgative class (n=136) characterized primarily by the use of indigenous Fijian herbal purgatives. Both ED classes endorsed greater eating pathology and general psychopathology than non-purging participants, and the herbal purgative class endorsed greater clinical impairment than either the BN-like or non-purging participants. Cultural orientation did not differ between the two ED classes.

Including study populations typically under-represented in mental health research and broadening the scope of relevant signs and symptoms in latent structure models may increase the generalizability of ED nosological schemes to encompass greater cultural diversity.

The main aim of this study was to compare a large population of patients with bipolar disorder (BD) types I and II strictly defined as euthymic with healthy controls on measures of decision making. An additional aim was to compare performance on a decision-making task between patients with and without a history of suicide attempt.

Eighty-five euthymic patients with BD-I or BD-II and 34 healthy controls were included. All subjects completed tests to assess verbal memory, attention and executive functions, and a decision-making paradigm (the Iowa Gambling Task, IGT).

Both groups of patients had worse performance than healthy controls on measures of verbal memory, attention and executive function. No significant differences were found between BD-I, BD-II and healthy controls on measures of decision making. By contrast, patients with a history of suicide attempt had lower performance in the IGT than patients without a history of suicide attempt.

Patients with euthymic BD-I and BD-II had intact decision-making abilities, suggesting that this does not represent a reliable trait marker of the disorder. In addition, our results provide further evidence of an association between impairments in decision making and vulnerability to suicidal behavior.