School-based online combined intervention reduces anxiety, alcohol use in adolescents

A school-based combined online intervention focusing on prevention of substance use, depression, and anxiety reduced alcohol consumption and anxiety symptoms in adolescents, a study from Australia showed.

“These findings provide the first evidence of the effectiveness of an online universal school-based preventive intervention targeting substance use, depression, and anxiety in adolescence,” said the authors led by Professor Maree Teesson from the University of Sydney, New South Wales, Australia.

The results were based on an analysis of 6,386 year 8 or 9 students (mean age 13.5 years, 54.8 percent female) from 71 secondary schools in Australia. The schools were randomized to receive one of four online interventions: Climate Schools–Substance Use (substance use-focus only, delivered through twelve 40-minute lessons); Climate Schools–Mental Health (depression and anxiety-focus only, delivered via six 40-minute lessons); Climate Schools–Combined (prevention of substance use, depression, and anxiety); or an active control (regular health education classes including mandatory lessons on mental health, alcohol, and drugs) for 2 years. The lessons were delivered during health education classes, with students in the schools randomized to the Combined intervention receiving the substance use course for 1 year and the mental health course the next year. Questionnaires were used to assess outcomes of the different interventions.

The Combined intervention led to greater knowledge of alcohol and cannabis compared with the control group at 12, 24, and 30 months (standardized mean difference [SMD], 0.57, 0.40, and 0.26, respectively; p<0.0001 for all [alcohol] and SMD, 0.59; p<0.0001, SMD, 0.33; p<0.0001, and SMD, 0.17; p=0.0021, respectively [cannabis]). [Lancet Digital Health 2020;doi:10.1016/S2589-7500(19)30213-4]

The Combined intervention was also associated with greater knowledge of mental health at 24 months vs the control group (SMD, 0.17; p=0.0003).

The Combined intervention was associated with a smaller increase in likelihood of drinking at 12, 24, and 30 months vs the control group (odds ratio [OR], 0.52; p=0.042, OR, 0.36; p=0.0031, and OR, 0.25; p=0.00013, respectively) or heavy episodic drinking (≥5 standard drinks on a single occasion; OR, 0.26; p=0.036, OR, 0.18; p=0.012, and OR, 0.15; p=0.0062, respectively).

There was a smaller increase in anxiety symptoms* at 12 and 30 months with the Combined intervention vs control (SMD, -0.11; p=0.010 and SMD, -0.12; p=0.029, respectively), while there was no difference in depression symptoms.

The Combined intervention was also better than the Substance Use intervention at increasing knowledge of cannabis at 12 and 24 months and knowledge of mental health at all three time points, and reducing likelihood of drinking at 24 and 30 months. It was also greater than the Mental Health Intervention at improving mental health knowledge at 12 months, and improving knowledge of alcohol and cannabis and reducing likelihood of drinking at all time points, as well as a reduced likelihood of a probable depression diagnosis** at 12 months and in anxiety symptoms at 12 and 30 months.

The apparent lack of superiority of the Combined vs other interventions pertaining to depression diagnosis points to the importance of long-term follow-up, up to early adulthood, when the onset of the condition often occurs and when there is increased exposure to substance use, said the authors.

“[P]revention programmes traditionally ignore co-occurrence of [alcohol use, anxiety, and depression],” said the authors. “Substance use, depression, and anxiety often share common risk factors. If we wish to address the major public health priority of substance use and mental ill health, continued research into novel and efficient programmes that target these problems together is crucial.”

“The Climate Schools–Combined intervention offers an interactive, scalable, and efficient approach to preventing the substantial burden of disease attributed to substance use and related disorders, and mental ill health,” they added.