Perceived risk associated with tobacco, alcohol and cannabis use among people with and without psychotic disorders.

BACKGROUND: Perceived harmfulness of substances is a key concept of behavioural theories that have been used to explain substance use behaviours. However, perceptions of risk associated with substance use have rarely been examined among people with psychotic disorders. This study examined the relationship between perceived harm and patterns of substance use among people with and without psychotic disorders. It also aimed to identify the factors that may be associated with perceived harmfulness of tobacco, alcohol and cannabis use among these populations.

METHODS: Participants were recruited via first year psychology courses, research databases and the social networking service 'Facebook'. Participants completed a self-report questionnaire either online or on paper which assessed substance use, perceived harmfulness of substance use, history of mental illness, current psychological distress, and exposure to and acceptance of anti-substance use campaigns. A series of linear regressions were conducted to examine key predictors of the perceived harmfulness of tobacco, alcohol and cannabis use.

RESULTS: 1046 participants were recruited. Participants were aged 18 to 86years and 53.2% were female. For tobacco and cannabis, substance use was found to be inversely and significantly related to perceived harm of these substances. In addition, higher risk perceptions for tobacco and cannabis were associated with: being female, perceived effectiveness of anti-substance use campaigns, and less hazardous substance use. Increased age and negative psychosis status were also associated with higher risk perceptions for tobacco, while positive psychosis status was associated with higher risk perceptions for cannabis. Only perceived effectiveness of anti-drinking campaigns was found to be significantly related to perceived harmfulness of alcohol.

CONCLUSIONS: These results suggest that demographic, substance use, mental health and public health campaign variables are associated with perceptions of the harmfulness of tobacco, cannabis, and to a lesser extent alcohol, among people with and without mental disorders. While messages regarding the negative consequences associated with cannabis use among people with psychotic disorders may be accepted, there is a continued need to highlight the negative consequences of smoking among people with psychotic disorders.