Substance use and their consequences account for substantial publicspending in Great Britain and Europe. However, alcohol and drug policy changeis often based on the harms attributed to a single drug, when polydrug use (theuse of more than one drug) is common and may increase associated harm. Thisresearch has employed advances in statistical analysis to createtypologies of polydrug use including alcohol and illicit drugs at a generalpopulation level in the 2000 National Psychiatric Morbidity Survey to better inform risks associated with these substances. Alcohol and drug use patterns were determined separately and then in an integrated model using latent class analysis. The relationship between the classes, demographic, and psychological status was assessed through multinomial logistic regression. Three drug classes, wide range, moderate range and no drug use represented illicit polydrug use. Sixalcohol classes were found, most of which followed a continuum of increasedconsumption relating to increased related problems, with one exception who experienced problems with low alcohol consumption. Any drug use elevated therisk for psychological conditions compared with the no drug use class, andincreased levels of alcohol consumption were related to increased risk ofgeneralised anxiety disorder and lifetime suicide attempts. Two integratedalcohol and illicit drug polydrug use models were proposed, one with eight andone with 18 classes. Further investigation of these models found two mainconclusions. First, illicit polydrug classes change when measured with alcoholuse, and the three classes were now ‘no drug’ use, ‘cannabis only’ and‘polydrug users’. This in turn affected relationship with demographic variablesand psychological status. Second, whilst alcohol use patterns do not changedramatically when measured in the presence of illicit drug use, there werechanges in relationships of alcohol with current psychological status as a consequence accounting for illicit drug use. Risk of poorer psychological healthis elevated in heavier patterns of alcohol use who also consume illicit drugscompared to the same alcohol pattern without illicit drug use.In conclusion, latent class analysis is a useful way in which to model populationlevel polydrug use. Through this methodology the consequences of separatingalcohol and illicit drug use in research have been shown. Research intoeither alcohol or illicit drug use should consider modelling both in the samemodel. The presentation of polydrug use in this context may be able toshow some of the ambiguities in the literature regarding demographicdifferences and risk relating to poorer psychological health.
- polydrug use
- substance use
- alcohol
- drug use
- mental health
- statistical modelling
- epidemiology
- latent class analysis
- latent variable analysis
- population data
Modelling patterns of polydrug use in the population of Great Britain: a latent class approach
Smith, G. W. (Author). Jul 2009
Student thesis: Doctoral Thesis