James E. Houston

Patterns of polydrug use in Great Britain: Findings from a national household population survey

BACKGROUND Polydrug use potentially increases the likelihood of harm. As little is known about polydrug use patterns in the general population, it is difficult to determine patterns associated with highest likelihood. METHODS Latent class analysis was performed on nine illicit substance groups indicating past year use of cannabis, cocaine, amphetamines, ecstasy, LSD, mushrooms, amyl nitrate, tranquillisers and heroin or crack. Analyses were based on data from a large multi-stage probability sample of the population of Great Britain (n=8538) collected in 2000. Multinomial logistic regression was performed highlighting associations between classes, and demographic and mental health variables. RESULTS A three class solution best described patterns of polydrug use; wide range, moderate range, and no polydrug use. For males and young people, there was a significantly increased chance of being in the wide and moderate range polydrug use groups compared to the no polydrug use class. Hazardous drinking was more likely in the wide and moderate polydrug classes with odds ratios of 9.99 and 2.38 (respectively) compared to the no polydrug use class. Current smokers were more likely to be wide and moderate range polydrug users compared to the no polydrug use class with odds ratios of 4.53 and 5.85 respectively. A range of mental health variables were also related to class membership. CONCLUSIONS Polydrug use in Great Britain can be expressed as three distinct classes. Hazardous alcohol use and tobacco use were strongly associated with illicit polydrug use, polydrug use appeared to be significantly associated with mental health, particularly lifetime suicide attempts.

A Population Based Analysis of Subclinical Psychosis and Help-Seeking Behavior

Clinically defined psychosis is recognizable and distinguishable from nonclinical or subclinical psychosis by virtue of its clinical relevance (ie, its associated distress and its need for care and/or treatment). According to the continuum hypothesis, subclinical psychosis is merely quantitatively different from more extreme phenotypic expressions and as such should also be indicative of distress and help-seeking behavior but to a lesser extent. Using data from the Adult Psychiatric Morbidity Survey, the current study focused on self-reported psychosis and help-seeking experiences in a general population sample free from clinically defined psychosis (N = 7266). After statistically controlling for the effects of a series of potential help-seeking correlates the findings showed that subclinical psychosis symptom experience was significantly associated with various forms of help-seeking behavior. Individuals who reported subclinical experiences of thought control, paranoia, and strange experiences were on average 2 times more likely to attend their general practitioner for emotional problems compared with those individuals who reported no psychosis. Individuals who reported subclinical experiences of paranoia were 3 times more likely to be in receipt of counseling/therapy compared with those with no experience of paranoia. Multiple subclinical psychotic experiences also predicted elevated help-seeking behavior. These findings may have a positive impact on the detection of individuals who are at increased risk of psychological distress and aid in the design and implementation of more effective treatments at both clinical and subclinical levels.

Childhood adversity and hallucinations: a community-based study using the National Comorbidity Survey Replication.

ObjectiveNumerous studies of both clinical and large-scale population based samples have demonstrated that adverse childhood events are risk factors for subsequent psychosis. This study assessed the relationships between adverse childhood events and auditory and visual hallucinatory experiences.MethodThe study analysed data from the National Comorbidity Survey Replication conducted in the US that assessed (all before age 16) rape, sexual assault and physical assault. Psychosis symptomatology was represented by lifetime experience of auditory and visual hallucinations. Control variables included gender, age, urbanity, ethnicity, marital status, education, employment status, alcohol dependence and drug dependence.ResultsAll three adverse events were significantly related to both types of hallucinations. Those who had been raped as children were 3.3 times more likely to have experienced visual hallucinations and 3.5 times more likely to have experienced auditory hallucinations compared to those who had not been raped in childhood. Both rape and physical assault significantly predicted visual and auditory hallucinations. A significant dose–response relationship was also found.ConclusionsPrevious findings indicating that adverse events in childhood may be causally related to subsequent psychosis are supported. The psychological and biological mechanisms underlying the relationship are already the subject of investigation. Repeated recommendations concerning routine enquiry about adverse experiences in childhood in order to facilitate comprehensive formulations and appropriate treatment, also receive support from these findings.

Cannabis use and psychosis: re-visiting the role of childhood trauma

BACKGROUND Cannabis consumption continues to be identified as a causal agent in the onset and development of psychosis. However, recent findings have shown that the effect of cannabis on psychosis may be moderated by childhood traumatic experiences. METHOD Using hierarchical multivariate logistic analyses the current study examined both the independent effect of cannabis consumption on psychosis diagnosis and the combined effect of cannabis consumption and childhood sexual abuse on psychosis diagnosis using data from the Adult Psychiatric Morbidity Survey 2007 (n=7403). RESULTS Findings suggested that cannabis consumption was predictive of psychosis diagnosis in a bivariate model; however, when estimated within a multivariate model that included childhood sexual abuse, the effect of cannabis use was attenuated and was not statistically significant. The multivariate analysis revealed that those who had experienced non-consensual sex in childhood were over six times [odds ratio (OR) 6.10] more likely to have had a diagnosis of psychosis compared with those who had not experienced this trauma. There was also a significant interaction. Individuals with a history of non-consensual sexual experience and cannabis consumption were over seven times more likely (OR 7.84) to have been diagnosed with psychosis compared with those without these experiences; however, this finding must be interpreted with caution as it emerged within an overall analytical step which was non-significant. CONCLUSIONS Future studies examining the effect of cannabis consumption on psychosis should adjust analyses for childhood trauma. Childhood trauma may advance existing gene-environment conceptualisations of the cannabis-psychosis link.

Excessive eating and compulsive buying behaviours in women: an empirical pilot study examining reward sensitivity, anxiety, impulsivity, self-esteem and social desirability

Abstract‘Mall disorders’ such as excessive eating and compulsive buying appear to be increasing, particularly among women. A battery of questionnaires was used in an attempt to determine this association between specific personality traits (i.e., reward sensitivity, impulsivity, cognitive and somatic anxiety, self-esteem, and social desirability) and excessive eating and compulsive buying in 134 women. Reward sensitivity and cognitive anxiety were positively related to excessive eating and compulsive buying, as was impulsivity to compulsive buying. Somatic anxiety and social desirability were negatively related to compulsive buying. These preliminary findings indicate that excessive behaviours are not necessarily interrelated. The behaviours examined in this study appear to act as an outlet for anxiety via the behaviours’ reinforcing properties (e.g., pleasure, attention, praise, etc.). As a consequence, this may boost self-esteem. The findings also appear to indicate a number of risk factors that could be used as ‘warning signs’ that the behaviour may develop into an addiction.

Evidence for a psychotic posttraumatic stress disorder subtype based on the National Comorbidity Survey.

PurposeThis study assessed the distribution of posttraumatic stress disorder (PTSD) symptoms and psychosis indicators among a large sample of individuals with a lifetime diagnosis of PTSD. The identification of a psychotic PTSD subtype was also predicted.MethodUsing data from the National Comorbidity Survey a latent class analysis was conducted on the PTSD symptoms of intrusion, avoidance, and hyperarousal and the psychosis hallucination and delusion indicators.ResultsResults indicated four latent classes, two of which had relatively high probabilities of endorsing the hallucination and delusion indicators. These classes were associated with a broad range of traumatic experiences. One particular class had high probabilities of endorsing both the psychosis indicators and the PTSD symptoms and was associated with a broad range of comorbid psychiatric disorders.ConclusionThere was a candidate class that met the characteristics expected to be evident in a psychotic PTSD subtype.

A person-centred approach to modelling population experiences of trauma and mental illness

BackgroundExposure to traumatic events has been implicated in the onset and development of a range of psychiatric disorders. People can be exposed to multiple traumatic events and previous research suggests that traumatic experiences may cluster at the individual level.MethodsThis study aimed to examine the distribution of traumatic experiences in a large nationally representative sample using latent class analysis, and estimate the relationship between these classes and a number of demographic and clinical variables. Data from the National Comorbidity Survey was used.ResultsFour latent classes, each representative of a range of traumatic experiences were identified. The classes were labelled ‘high risk’ (class 1), ‘exposure to non-sexual adult interpersonal/non-interpersonal trauma’ (class 2), ‘intermediate risk/sexual abuse’ (class 3), and ‘low risk’ (class 4). Each of the latent classes was predicted by several of the demographic variables. In addition, membership of classes 1, 2, and 3 increased the risk of each of the clinical variables.ConclusionsThe findings have clinical implications for the assessment of trauma histories across a range of psychiatric diagnoses.

Childhood sexual abuse, early cannabis use, and psychosis: Testing the effects of different temporal orderings based on the National Comorbidity Survey

Research has shown that childhood sexual abuse and cannabis use below the age of 16 significantly increased the risk of psychosis. The aim of this study was to estimate the effects of the different temporal ordering of exposure to cannabis and sexual trauma on psychosis. Data from the National Comorbidity Survey were used to construct a variable representing different exposures (no sexual trauma or cannabis use, sexual trauma only, cannabis use only, sexual trauma preceded cannabis use, cannabis use preceded sexual trauma). A hierarchical binary logistic regression model was specified with a diagnosis of psychosis as the dependent variable, background variables entered in the first block and the sexual trauma and cannabis use variable entered in the second block. The results indicated that sexual trauma with no cannabis use increased the risk of psychosis (OR=2.45, p<.05), and the risk increased for cannabis use before (OR=4.39, p<.05) or after (OR=4.25, p<.05) sexual trauma. The findings are discussed with reference to the existing research literature on the development of psychosis symptoms.

Positive psychosis symptom structure in the general population: Assessing dimensional consistency and continuity from 'pathology' to 'normalty'

The current study assessed the dimensionality of positive psychosis symptoms. Data from the National Comorbidity Survey (1990–1992) was used to examine the underlying factor structure of positive psychosis symptoms based on participants’ responses to the 13 Composite International Diagnostic Interview (CIDI) psychosis screening items. Confirmatory factor analysis (CFA) was used to compare four theoretically based competing factor analytic models of positive psychosis. Fit statistics indicated that the best fitting model was comprised of three correlated factors: a hallucinations factor, a Schneiderian delusions factor, and a paranoid delusions factor. There were no significant differences between the sexes on scores for the Schneiderian Delusions and Paranoid dimensions; however, females scored significantly higher on the Hallucinations dimension. At an item level, male respondents were significantly more likely to report experiences of paranoia; being controlled by an external force; and having their thoughts stolen by another. Females, on the other hand, were significantly more likely to experience auditory, olfactory, and tactile hallucinations. They were also more likely to believe that others were reading their mind. The three underlying factors were consistent with existing clinical models of positive psychosis symptom dimensionality and provide further evidence of a continuum of psychosis.

Development of the Multidimensional Peer Victimization Scale–Revised (MPVS-R) and the Multidimensional Peer Bullying Scale (MPVS-RB)

ABSTRACT Peer victimization is a frequent occurrence for many adolescents; however, some of the psychometric properties of self-report scales assessing these experiences remain unclear. Furthermore, with an increase in access to technology, electronic aggression should also be considered. The authors examined the psychometric properties of the Multidimensional Peer Victimization Scale (MPVS; Mynard & Joseph, 2000), and developed versions to include the assessment of electronic aggression according to whether the adolescent was the target or perpetrator of peer victimization. A total of 371 (191 girls and 180 boys; Mage = 13 years 4 months, SDage = 1 year 2 months) adolescents in the United Kingdom completed the MPVS including five newly developed items assessing electronic aggression, a version of the MPVS designed to assess victimization perpetration, and a measure of self-esteem. Confirmatory factor analyses yielded a five-factor structure comprising: Physical, social manipulation, verbal, attacks on property, and electronic for both scales. Convergent validity was established through negative associations between the victimization scales and self-esteem. Sex differences also emerged. One revised scale and one new scale are subsequently proposed: The MPVS–Revised and the Multidimensional Peer Bullying Scale.