An examination of substance use profiles and mental health in private households of Great Britain

1. The latent structure of polysubstance use: An examination of substance use profiles and mental health in private households of Great Britain Gillian Smith, Mark Shevlin & Brendan Bunting Psychology Research Institute University of Ulster Northern Ireland Smith-g2@ulster.ac.uk

2. Overview • Introduction • Why need to study polysubstance use? • Data set and methods • Patterns of polysubstance use • Demographic variables and Mental Health conditions • Conclusions and Implications

3. Why look at patterns of drug use? • Polydrug use increases the likelihood of physical or psychological damage (Forsyth, 1996; Feigelman, Gorman & Lee, 1998; Riley et al., 2001). • Understanding polysubstance use is necessary before finding out the effect of a single drug (Topp, Hando, Dillon, Roche & Solowij, 1999; Grob, 2000) • All Ecstasy users who use other drugs confound interpretation of drugs effect (Cole & Sumnall, 2003)

4. Most likely profile for psychological disorders • Green et al. (2003) “risk profiles” and substance use Literature suggests that • Females • Urban dwellers • Lower educational attainment and unemployed ….are more likely to have a mental health condition. (e.g. Kessler et al, 2003; Kovess-Masfety, Lecoutour and Delavelle, 2005; Fryers, Meltzer and Jenkins, 2003)

5. Data from the Psychiatric Morbidity among adults living in private households (Singleton et al, 2001) 8541 participants aged 16-74 in England, Scotland and Wales (39 missing or endorsed fictional drug ‘semeron’) Used Mplus v3.01 (Muthen & Muthen, 2004) Latent class analysis can be used to discover subgroups or classes of observations similar to each other on various observed categorical variables Relations between the classes and demographic/mental health variables will be assessed using multinomial logistic regression Optimum model selection using 2 times loglikelihood difference testing. Data & Analysis

6. Graph 1: Profile of the latent classes in terms of their endorsement of each of the substances.

7. Demographic variables Sex Education Area type Employment Age and Currently Smoking AUDIT score Mental Health variables Generalised anxiety disorder Mixed anxiety and depression Depressive ideas Suicide attempt Psychosis Multinomial logistic regression Comparing the wide and moderate range classes to baseline little/no range class

8. Table 1: Odds ratios and 95% confidence intervals (CI) for the latent class model with covariates.

9. Conclusions • Strong relationship between hazardous alcohol use, smoking and wide or moderate substance use • Given that alcohol use initiation is earlier than drug use initiation, perhaps an intervention around time of alcohol use developmental stage • Application of the Latent Class Analysis technique to accounting for substance use heterogeneity • Use of cannabis, cocaine, ecstasy and amphetamines appear to cluster together • Use of LSD, magic mushrooms, tranquillisers and amyl nitrate appear to cluster together

10. Conclusions • Profiles derived from the data demonstrated that neither “wide” nor “moderate” polydrug users had the most likely demographic profile for mental health disorders compared to “little/no” range users • As their risk was significantly elevated in comparison to the baseline class to have a mental health condition, it can be suggested that any substance use increases the risk • Further research will determine whether there are quantitative differences between substance use within profiles