The effectiveness of an indicated prevention programme for substance use in individuals with mild intellectual disabilities and borderline intellectual functioning: results of a quasi‐experimental study

AIMS: To assess the effectiveness of Take it personal!, a prevention programme for individuals with mild intellectual disabilities and borderline intellectual functioning (MID‐BIF) and substance use (SU). The prevention programme aims to reduce SU (alcohol, cannabis and illicit drugs) among experimental to problematic substance users. DESIGN: A quasi‐experimental design with two arms and a 3‐month follow‐up. SETTING: Adolescents were recruited from 14 treatment centres in the Netherlands specialized in offering intra‐ and extramural care for people with MID‐BIF and behavioural problems. PARTICIPANTS: Data were collected from 66 individuals with MID‐BIF assigned either to the intervention condition (n = 34) or to the control condition (n = 32). INTERVENTIONS: Take it personal! was designed to target four personality traits: sensation‐seeking, impulsive behaviour, anxiety sensitivity and negative thinking. For each of these profiles, interventions were developed that were structurally the same but contained different personality‐specific materials, games and exercises. The control group received care as usual. MEASUREMENTS: Primary outcomes at 3‐month follow‐up were frequency of SU, severity of SU and binge drinking. RESULTS: Results showed intervention effects for SU frequency (F ((1, 50.43)) = 9.27, P = 0.004) and binge drinking (F ((1, 48.02)) = 8.63, P = 0.005), but not for severity of SU (F ((1, 42.09)) = 2.20, P = 0.145). CONCLUSIONS: A prevention programme to reduce substance use among experimental to problematic users with mild intellectual disabilities and borderline intellectual functioning helped participants to decrease substance use frequency and binge drinking.