The link between substance use, mental health, and other lifestyle behaviours

Alcohol use is associated with later sleep times, oversleeping, and poor-quality sleep. Restless or poor-quality sleep has also been shown to predict early onset of alcohol use. People with moderate to heavy alcohol use are also more likely to have unhealthy lifestyles overall, characterised by a poor diet and cigarette use. Additionally, consumption of foods high in fat and sugar has been linked with regular alcohol use.

Avoiding alcohol use in adolescence has been associated with better physical health, reduced aggression, improved self-regulation, and lower rates of depression and anxiety.

Research suggests that abstaining from cigarette smoking in adolescence decreases the odds of having mental health symptoms and other substance use disorders. Adolescent tobacco smoking increases the likelihood of early adult tobacco use, the initiation of alcohol use, and the subsequent development of alcohol related problems. Also, cigarette smoking and sleep have a bi-directional relationship in youth.

Young people who do not smoke tend to have more consistency between their weekend and weekday bedtime and an earlier wake-up time on weekends. Young people who do not smoke are also less likely to develop alcohol use disorders, and are less likely to meet criteria for mood disorders, anxiety disorders, and psychosis, when compared to smokers.

A healthy diet that limits consumption of sugar sweetened beverages leads to better adherence to screen time guidelines and longer sleep duration in adolescents. High fat snacking also tends to co-occur with TV viewing. A healthy diet may also protect adolescents from problematic alcohol use, as diets high in fat and sugar during childhood have been shown to predict regular use of alcohol in adolescence.

A healthy diet high in fruits and vegetables, and low in added sugar and fats, have been shown to improve mental health. Specifically, a healthy diet can protect adolescents from emotional and behavioural problems and is critical for learning and memory.

Physical activity has been found to be positively related to diet, sleep, and non-smoking. For example, young people who achieve the recommended amounts of physical activity are more likely to eat healthily, abstain from smoking, and report falling asleep earlier and feeling less tired throughout their day.

In contrast, regular physical activity has been associated with a decreased risk of sadness, low self-esteem, and depressive symptoms in adolescence. Physical activity also helps to improve sleep quality which in turn helps maintain mood and reduces fatigue.

Healthy sleep duration has been associated with a higher likelihood of fruit consumption, vegetable consumption, water consumption, physical activity, and muscle-strengthening physical activity, and with a reduced likelihood of cigarette use, alcohol use, and intake of sugary drinks and treats.

Achieving the recommended amount of sleep has been associated with improved mood and better academic performance.

Excessive screen time has been associated with delayed bedtimes and reduced total sleep duration. Additionally, TV viewing is associated with lower intake of protein, minerals, vitamins, and total dietary fibre, and an increase in high-fat snacking.

Limiting recreational screen time has been shown to predict higher levels of physical activity.