Feeding the addiction: Narrowing of goals to habits.

Whilst the initiation of cocaine use is typically goal-directed and motivated by the rewarding effects of the drug, drug-taking can become habitual over time, rendering the user less sensitive to cocaine's hedonic value. Experimental studies suggest that patients with cocaine use disorder (CUD) are particularly prone to develop habits, even in non-drug related contexts. CUD patients have previously been shown to consume higher levels of high-calorie foods and report more uncontrolled eating, suggesting a tendency towards habitual or dysregulated food-related behaviours. We investigated this in CUD patients compared with healthy controls. Participants were presented with a series of food images and asked to rate their willingness to pay for, and their motivation to consume the foods. Self-reported motivations for food choices were collected using a validated questionnaire. Our data suggests CUD patients display goal-narrowing towards cocaine, as well as habitual tendencies towards both cocaine and food. These findings stress the importance of addressing non-drug related behaviours when treating CUD patients. Further, they suggest that habits may provide a novel and additional target for psychological interventions, for example, through the retraining of maladaptive habits. Whilst research into the feasibility and efficacy of habit retraining is certainly required, the potential for a new avenue of treatment should not be ignored.

Embracing the positive: an examination of how well resilience factors at age 14 can predict distress at age 17.

One-in-two people suffering from mental health problems develop such distress before or during adolescence. Research has shown that distress can predict itself well over time. Yet, little is known about how well resilience factors (RFs), i.e. those factors that decrease mental health problems, predict subsequent distress. Therefore, we investigated which RFs are the best indicators for subsequent distress and with what accuracy RFs predict subsequent distress. We examined three interpersonal (e.g. friendships) and seven intrapersonal RFs (e.g. self-esteem) and distress in 1130 adolescents, at age 14 and 17. We estimated the RFs and a continuous distress-index using factor analyses, and ordinal distress-classes using factor mixture models. We then examined how well age-14 RFs and age-14 distress predict age-17 distress, using stepwise linear regressions, relative importance analyses, as well as ordinal and linear prediction models. Low brooding, low negative and high positive self-esteem RFs were the most important indicators for age-17 distress. RFs and age-14 distress predicted age-17 distress similarly. The accuracy was acceptable for ordinal (low/moderate/high age-17 distress-classes: 62-64%), but low for linear models (37-41%). Crucially, the accuracy remained similar when only self-esteem and brooding RFs were used instead of all ten RFs (ordinal = 62%; linear = 37%); correctly predicting for about two-in-three adolescents whether they have low, moderate or high distress 3 years later. RFs, and particularly brooding and self-esteem, seem to predict subsequent distress similarly well as distress can predict itself. As assessing brooding and self-esteem can be strength-focussed and is time-efficient, those RFs may be promising for risk-detection and translational intervention research.

Unravelling the complex nature of resilience factors and their changes between early and later adolescence.

BACKGROUND: Childhood adversity (CA) is strongly associated with mental health problems. Resilience factors (RFs) reduce mental health problems following CA. Yet, knowledge on the nature of RFs is scarce. Therefore, we examined RF mean levels, RF interrelations, RF-distress pathways, and their changes between early (age 14) and later adolescence (age 17). METHODS: We studied 10 empirically supported RFs in adolescents with (CA+; n = 631) and without CA (CA-; n = 499), using network psychometrics. RESULTS: All inter-personal RFs (e.g. friendships) showed stable mean levels between age 14 and 17, and three of seven intra-personal RFs (e.g. distress tolerance) changed in a similar manner in the two groups. The CA+ group had lower RFs and higher distress at both ages. Thus, CA does not seem to inhibit RF changes, but to increase the risk of persistently lower RFs. At age 14, but not 17, the RF network of the CA+ group was less positively connected, suggesting that RFs are less likely to enhance each other than in the CA- group. Those findings underpin the notion that CA has a predominantly strong proximal effect. RF-distress pathways did not differ in strength between the CA+ and the CA- group, which suggests that RFs have a similarly protective strength in the two groups. Yet, as RFs are lower and distress is higher, RF-distress pathways may overall be less advantageous in the CA+ group. Most RF interrelations and RF-distress pathways were stable between age 14 and 17, which may help explain why exposure to CA is frequently found to have a lasting impact on mental health. CONCLUSIONS: Our findings not only shed light on the nature and changes of RFs between early and later adolescence, but also offer some accounts for why exposure to CA has stronger proximal effects and is often found to have a lasting impact on mental health.

Identifying key targets for interventions to improve psychological wellbeing: replicable results from four UK cohorts.

BACKGROUND: An increasing importance is being placed on mental health and wellbeing at individual and population levels. While there are several interventions that have been proposed to improve wellbeing, more evidence is needed to understand which aspects of wellbeing are most influential. This study aimed to identify key items that signal improvement of mental health and wellbeing. METHODS: Using network analysis, we identified the most central items in the graph network estimated from the well-established Warwick-Edinburgh Mental Well-being Scale (WEMWBS). Results were compared across four major UK cohorts comprising a total of 47,578 individuals: the Neuroscience in Psychiatry Network, the Scottish Schools Adolescent Lifestyle and Substance Use Survey, the Northern Ireland Health Survey, and the National Child Development Study. RESULTS: Regardless of gender, the three items most central in the network were related to positive self-perception and mood: 'I have been feeling good about myself'; 'I have been feeling confident'; and 'I have been feeling cheerful'. Results were consistent across all four cohorts. CONCLUSIONS: Positive self-perception and positive mood are central to psychological wellbeing. Psychotherapeutic and public mental health interventions might best promote psychological wellbeing by prioritising the improvement of self-esteem, self-confidence and cheerfulness. However, empirical testing of interventions using these key targets is needed.

Childhood inflammatory markers and intelligence as predictors of subsequent persistent depressive symptoms: a longitudinal cohort study.

BACKGROUND: To identify developmental sub-groups of depressive symptoms during the second decade of life, a critical period of brain development, using data from a prospective birth cohort. To test whether childhood intelligence and inflammatory markers are associated with subsequent persistent depressive symptoms. METHODS: IQ, a proxy for neurodevelopment, was measured at age 8 years. Interleukin 6 (IL-6) and C-reactive protein, typical inflammatory markers, were measured at age 9 years. Depressive symptoms were measured six times between 10 and 19 years using the short mood and feelings questionnaire (SMFQ), which were coded as binary variable and then used in latent class analysis to identify developmental sub-groups of depressive symptoms. RESULTS: Longitudinal SMFQ data from 9156 participants yielded three distinct population sub-groups of depressive symptoms: no symptoms (81.2%); adolescent-onset symptoms (13.2%); persistent symptoms (5.6%). Lower IQ and higher IL-6 levels in childhood were independently associated with subsequent persistent depressive symptoms in a linear, dose-response fashion, but not with adolescent-onset symptoms. Compared with the group with no symptoms the adjusted odds ratio for persistent depressive symptoms per s.d. increase in IQ was 0.80 (95% CI, 0.68-0.95); that for IL-6 was 1.20 (95% CI, 1.03-1.39). Evidence for an association with IL-6 remained after controlling for initial severity of depressive symptoms at 10 years. There was no evidence that IL-6 moderated or mediated the IQ-persistent depressive symptom relationship. CONCLUSIONS: The results indicate potentially important roles for two distinct biological processes, neurodevelopment and inflammation, in the aetiology of persistent depressive symptoms in young people.

Latent traits of impulsivity and compulsivity: toward dimensional psychiatry.

BACKGROUND: The concepts of impulsivity and compulsivity are commonly used in psychiatry. Little is known about whether different manifest measures of impulsivity and compulsivity (behavior, personality, and cognition) map onto underlying latent traits; and if so, their inter-relationship. METHODS: A total of 576 adults were recruited using media advertisements. Psychopathological, personality, and cognitive measures of impulsivity and compulsivity were completed. Confirmatory factor analysis was used to identify the optimal model. RESULTS: The data were best explained by a two-factor model, corresponding to latent traits of impulsivity and compulsivity, respectively, which were positively correlated with each other. This model was statistically superior to the alternative models of their being one underlying factor ('disinhibition') or two anticorrelated factors. Higher scores on the impulsive and compulsive latent factors were each significantly associated with worse quality of life (both p < 0.0001). CONCLUSIONS: This study supports the existence of latent functionally impairing dimensional forms of impulsivity and compulsivity, which are positively correlated. Future work should examine the neurobiological and neurochemical underpinnings of these latent traits; and explore whether they can be used as candidate treatment targets. The findings have implications for diagnostic classification systems, suggesting that combining categorical and dimensional approaches may be valuable and clinically relevant.

First-rank symptoms and premorbid adjustment in young individuals at increased risk of developing psychosis.

BACKGROUND: Individuals at clinical high risk (CHR) for psychosis represent a heterogeneous group with a high rate of comorbid psychiatric disorders. There is little information on whether certain qualitative aspects of psychotic symptoms among CHR individuals may be predictive of future psychosis. This study focused on describing the prevalence of first-rank symptoms (FRS) among a sample of CHR individuals and its association with future transition to psychosis and, from a neurodevelopmental perspective, the level of adjustment of individuals at CHR during their childhood was also analysed. SAMPLING AND METHODS: Participants comprised 60 individuals at CHR (according to the Comprehensive Assessment of At-Risk Mental States, CAARMS) at the time of their referral to an early intervention service and 60 healthy volunteers (HVs). All subjects were assessed by senior research clinicians using the Mini International Neuropsychiatric Interview (MINI), and the Positive and Negative Syndrome Scale (PANSS). FRS were defined according to Kurt Schneider's original classification, and information was collected from PANSS, CAARMS and clinical reports. Early premorbid functioning was measured using the Premorbid Adjustment Scale (PAS). We grouped individuals by number and type of FRS and analysed transitions to full-blown psychosis over a 2-year follow-up period. We also correlated the general social and functional adjustment of these individuals during their childhood (6-11 years of age) with the future development of mental states at CHR and FRS. RESULTS: Over 69% of CHR individuals had more than one DSM-IV psychiatric diagnosis, mainly within the affective and anxiety diagnostic spectra. At least one FRS was present in 43.3% of CHR individuals, and 21.6% of these had more than one. Auditory hallucinations and passivity experiences were the most commonly reported. Only 10% of individuals at CHR made a transition to first-episode psychosis (FEP) over 2 years and, except for passivity experiences, the presence of one or more FRS was not significantly associated with the transition to FEP. CHR individuals, especially those with FRS, had poorer premorbid functioning and adjustment as children across educational, social and peer relationship domains than HVs. However, this was not associated with FEP 2 years later. CONCLUSIONS: FRS might not be indicators of psychosis alone but of different psychiatric disorders. In line with the neurodevelopmental model of psychosis, individuals at CHR might be exhibiting several vulnerability traits and manifestations of abnormal developmental processes that might predict a future psychiatric disorder and/or long-term impairment.

Social and spatial heterogeneity in psychosis proneness in a multilevel case-prodrome-control study.

OBJECTIVE: To test whether spatial and social neighbourhood patterning of people at ultra-high risk (UHR) of psychosis differs from first-episode psychosis (FEP) participants or controls and to determine whether exposure to different social environments is evident before disorder onset. METHOD: We tested differences in the spatial distributions of representative samples of FEP, UHR and control participants and fitted two-level multinomial logistic regression models, adjusted for individual-level covariates, to examine group differences in neighbourhood-level characteristics. RESULTS: The spatial distribution of controls (n = 41) differed from UHR (n = 48; P = 0.04) and FEP participants (n = 159; P = 0.01), whose distribution was similar (P = 0.17). Risk in FEP and UHR groups was associated with the same neighbourhood-level exposures: proportion of single-parent households [FEP adjusted odds ratio (aOR): 1.56 95% CI: 1.00-2.45; UHR aOR: 1.59; 95% CI: 0.99-2.57], ethnic diversity (FEP aOR: 1.27; 95% CI: 1.02-1.58; UHR aOR: 1.28; 95% CI: 1.00-1.63) and multiple deprivation (FEP aOR: 0.88; 95% CI: 0.78-1.00; UHR aOR: 0.86; 95% CI: 0.76-0.99). CONCLUSION: Similar neighbourhood-level exposures predicted UHR and FEP risk, whose residential patterning was closer to each other's than controls. Adverse social environments are associated with psychosis before FEP onset.

Mood, anxiety and psychotic phenomena measure a common psychopathological factor.

BACKGROUND: Psychotic phenomena are common in the general population but are excluded from diagnostic criteria for mild to moderate depression and anxiety despite their co-occurrence and shared risk factors. We used item response theory modelling to examine whether the co-occurrence of depressive, anxiety and psychotic phenomena is best explained by: (1) a single underlying factor; (2) two separate, uncorrelated factors; (3) two separate yet linked factors; or (4) two separate domains along with an underlying 'common mental distress' (CMD) factor. We defined where, along any latent continuum, the psychopathological items contributed most information. METHOD: We performed a secondary analysis of cross-sectional, item-level information from measures of depression, anxiety and psychotic experiences in 6617 participants aged 13 years from the Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort and 977 participants aged 18 years from the ROOTS schools-based sample. We replicated results from one sample in the other and validated the latent factors against an earlier parental measure of mental state. RESULTS: In both cohorts depression, anxiety and psychotic items were best represented as a bi-factor model with a single, unitary CMD factor on which psychotic items conveyed information about the more severe end (model 4); residual variation remained for psychotic items. The CMD factor was significantly associated with the prior parental measure. CONCLUSIONS: Psychotic phenomena co-occur with depression and anxiety in teenagers and may be a marker of severity in a single, unitary dimension of CMD. Psychotic phenomena should be routinely included in epidemiological assessments of psychiatric morbidity, otherwise the most severe symptomatology remains unmeasured.

A population-based longitudinal study of childhood neurodevelopmental disorders, IQ and subsequent risk of psychotic experiences in adolescence.

BACKGROUND: Schizophrenia has a neurodevelopmental component to its origin, and may share overlapping pathogenic mechanisms with childhood neurodevelopmental disorders (NDs). Nevertheless, longitudinal studies of psychotic outcomes among individuals with NDs are limited. We report a population-based prospective study of six common childhood NDs, subsequent neurocognitive performance and the risk of psychotic experiences (PEs) in early adolescence. METHOD: PEs were assessed by semi-structured interviews at age 13 years. IQ and working memory were measured between ages 9 and 11 years. The presence of six NDs (autism spectrum, dyslexia, dyspraxia, dysgraphia, dysorthographia, dyscalculia) was determined from parent-completed questionnaires at age 9 years. Linear regression calculated the mean difference in cognitive scores between children with and without NDs. Associations between NDs and PEs were expressed as odds ratios (ORs) with 95% confidence intervals (CIs); effects of cognitive deficits were examined. Potential confounders included age, gender, father's social class, ethnicity and maternal education. RESULTS: Out of 8220 children, 487 (5.9%) were reported to have NDs at age 9 years. Children with, compared with those without, NDs performed worse on all cognitive measures; the adjusted mean difference in total IQ was 6.84 (95% CI 5.00-8.69). The association between total IQ and NDs was linear (p < 0.0001). The risk of PEs was higher in those with, compared with those without, NDs; the adjusted OR for definite PEs was 1.76 (95% CI 1.11-2.79). IQ (but not working memory) deficit partly explained this association. CONCLUSIONS: Higher risk of PEs in early adolescence among individuals with childhood ND is consistent with the neurodevelopmental hypothesis of schizophrenia.

Common versus psychopathology-specific risk factors for psychotic experiences and depression during adolescence.

BACKGROUND: An argument often used to support the view that psychotic experiences (PEs) in general population samples are a valid phenotype for studying the aetiology of schizophrenia is that risk factors for schizophrenia show similar patterns of association with PEs. However, PEs often co-occur with depression, and no study has explicitly tested whether risk factors for schizophrenia are shared between PEs and depression, or are psychopathology specific, while jointly modelling both outcomes. METHOD: We used data from 7030 subjects from a birth cohort study. Depression and PEs at age 18 years were assessed using self-report questionnaires and semi-structured interviews. We compared the extent to which risk factors for schizophrenia across sociodemographic, familial, neurodevelopmental, stress-adversity, emotional-behavioural and substance use domains showed different associations with PEs and depression within bivariate models that allowed for their correlation. RESULTS: Most of the exposures examined were associated, to a similar degree, with an increased risk of both outcomes. However, whereas female sex and family history of depression showed some discrimination as potential risk factors for depression and PEs, with stronger associations in the former, markers of abnormal neurodevelopment showed stronger associations with PEs. CONCLUSIONS: The argument that PEs are valid markers for studying the aetiology of schizophrenia, made simply on the basis that they share risk factors in common, is not well supported. PEs seem to be a weak index of genetic and environmental risk for schizophrenia; however, studies disentangling aetiological pathways to PEs from those impacting upon co-morbid psychopathology might provide important insights into the aetiology of psychotic disorders.

Clinical and sociodemographic comparison of people at high-risk for psychosis and with first-episode psychosis.

OBJECTIVE: To compare clinical and sociodemographic characteristics previously associated with psychosis, between individuals at high-risk for psychosis (HR) and patients experiencing a first episode psychosis (FEP), to achieve a better understanding of factors associated with psychosis. METHOD: Cross-sectional comparison of 30 individuals at HR with 30 age-gender matched FEP, presenting to an early intervention service for psychosis. Participants were followed-up for 2 years to establish the proportion of HR who made the transition into FEP. RESULTS: Both groups showed similar socio-clinical characteristics, including immigration status, employment history, marital status, family history of psychotic illness, self-harm and alcohol and drug use. The HR group had a lower level of education, higher burden of trauma, earlier onset of psychiatric symptoms and a longer delay in accessing specialised services. A younger onset of symptoms was associated with a longer delay in accessing services in both groups. After a 2 year follow-up, only three (10%) of the HR group made a transition into FEP. CONCLUSION: The similarities observed between individuals at HR and those with FEP suggest that known variables associated with psychosis may be equally prevalent in people at HR who do not develop a psychotic disorder.

Usefulness of EQ-5D for evaluation of health-related quality of life in young adults with first-episode psychosis.

PURPOSE: To evaluate the psychometric properties of the EQ-5D and the usefulness of this instrument in psychiatric practice as a measure of health-related quality of life (HRQoL) in a sample of young adults with first-episode psychosis. METHODS: The validity of individual questionnaire items is studied using an Item Response/Latent Trait Theory modeling approach. Sensitivity of response patterns on EQ-5D items to particular diagnostic subtypes of psychosis is investigated using a finite mixture modeling approach through latent class analysis. Finally, a structural equation modeling framework is used to study differential item functioning via a multigroup approach. RESULTS: Results suggest that the data closely correspond to the Rasch Rating Scale Model, and therefore that EQ-5D latent scores are equal interval measures. Despite comprising relatively few items, the instrument yields reliable measures of HRQoL for group comparisons and cost-effectiveness evaluation, but EQ-5D score is too imprecise for the assessment of HRQoL for clinical purposes at the individual level. A significant relationship was found between EQ-5D responses and type of psychosis due to inclusion of item anxiety/depression in EQ-5D. Two items (anxiety/depression, functioning in usual activities) showed an ethnicity bias. CONCLUSIONS: Psychometric evidence confirmed the EQ-5D to be a valid, interval measure that is scalable according to Rasch principles.