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

Icons of physcial activity, diet, sleep, screen time, alcohol and smoking
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This resource has undergone expert review.

Year 3–4, Year 5–6, Year 7–8, Year 9–10, Year 11–12




Lifestyle risk behaviours and chronic disease

During adolescence, many habits and routines are formed which often continue into adulthood. This is especially true for lifestyle risk behaviours. Lifestyle risk behaviours have been identified as major causes of chronic diseases (e.g., obesity, type 2 diabetes, and cardiovascular disease) and mental health problems, such as depression and anxiety. The Big 6 lifestyle risk behaviours that often emerge during adolescence are:

  • Alcohol use
  • Smoking
  • Poor diet
  • Physical inactivity
  • Poor sleep (long or short duration and/or poor quality)
  • Sedentary recreational screen time

A recent study investigated the prevalence of the Big 6 lifestyle risk behaviours among a sample of 6,640 Australian 11-14 year olds (12.7 years on average). The prevalence of these behaviours among this group is shown below.

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

Lifestyle risk behaviours commonly co-occur. For example, adolescents who use alcohol or other drugs are also more likely to eat poorly. In fact, research shows that 63% of Australian teenagers engage in three or more risk behaviours, and 26% engage in four or more at a given time. Additionally, the strongest associations are often seen between substance use and other risk behaviours, where adolescents who initiate alcohol or other drug use at an earlier age are more likely to concurrently engage in other lifestyle risk behaviours.

Helping young people improve one health behaviour can motivate them to improve another health behaviour, this is known as multiple health behaviour change. See below for examples of how the Big 6 lifestyle risk behaviours affect  one another and how engaging in healthy behaviours can improve both physical and mental health.

Alcohol use

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

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.


Screen time

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.

Promoting healthy behaviours

Engaging in healthy behaviours can not only improve physical health, but is also important for promoting good mental health. Below are some recommended guidelines for the different health behaviours and how you, as a teacher, can encourage healthy habits among young people.

Alcohol use

  • In Australia, alcohol guidelines are outlined by the National Health and Medical Research Council (NHMRC).
  • For children under 18 years of age the guidelines state:
  • People under 18 are particularly vulnerable to the harmful effects of alcohol as the body and brain are still developing. Therefore, it’s important to encourage the delay of alcohol consumption for as long as possible.
  • Schools play an important role in alcohol and other drug prevention. Multi-component school based programs that have been developed and tested in Australia have been shown to prevent and reduce alcohol consumption among young people. View our library of recommended programs you can implement at your school.
  • Read more about school-based drug and alcohol prevention: What works?


  • Cigarette smoking is linked to numerous immediate and long-term effects. Therefore, it is recommended that young people stay smoke free.
  • Similar to preventing alcohol use, school-based programs have proven effectiveness in preventing smoking. One specific smoking prevention program is Aspire.
  • If you think a student or someone else is smoking or using another substance see our factsheet on Talking to a young person about alcohol and other drugs for tips on communicating effectively and supporting students.


  • The Australian Dietary Guidelines provide up-to-date research based recommendations for eating healthy and promoting wellbeing.
  • The five dietary guidelines include:
    • Guideline 1: To achieve and maintain a healthy weight, be physically active and choose amounts of nutritious food and drinks to meet your energy needs.
    • Guideline 2: Enjoy a wide variety of nutritious foods from these five food groups every day:
      • Plenty of vegetables, including different types and colours, and legumes/beans.
      • Grain (cereal) foods, mostly wholegrain and/or high cereal fibre varieties, such as breads, cereals, rice, pasta, noodles, polenta, couscous, oats, quinoa, and barley.
      • Lean meats and poultry, fish, eggs, tofu, nuts and seeds, and legumes/beans.
      • Milk, yoghurt, cheese and/or their alternatives, mostly reduced fat.
      • And drink plenty of water.
    • Guideline 3: Limit intake of foods containing saturated fat, added salt, added sugars and alcohol.
    • Guideline 4: Encourage, support, and promote breastfeeding.
    • Guideline 5: Care for your food; prepare and store it safely.
  • Teachers can help encourage good nutritional habits in a variety of ways both in the classroom and in the school environment more broadly. Some ideas include:
    • Develop a school vegetable garden.
    • Display dietary guidelines posters or brochures in the classroom.
    • Make celebrations or school fundraisers healthier.
    • Use non-food rewards (pencils, skipping ropes) instead of lollies and sweets.
    • Allow students to bring their water bottle into the classroom with them.
    • Offer healthy foods in the school canteen.

Physical activity

  • Physical activity guidelines recommend children and young people aged 5-17 should aim for 60 minutes per day of moderate to vigorous physical activity.
  • It doesn’t have to be the full 60 minutes at once, multiple shorter sessions can be accumulated throughout the day.
  • Vigorous activity doesn’t have to be organised team sport or structured activities. It can include activities such as: dancing, martial arts, bike riding over to a friend’s house, playing soccer with friends during lunch time, surfing or swimming.
  • The guidelines also recommend incorporating muscle strengthening activities a few times a week. Examples of muscle strengthening activities include running, climbing, yoga, and weight lifting.
  • It’s also important for young people to limit sedentary behaviour (i.e., time sitting down especially on screens) and include several hours of light physical activity each day including walking to school, helping around the house, or playing with friends outdoors.  


  • Getting enough good-quality sleep is vital for rest, recovery, and healthy development.
  • Sleep recommendations differ across age groups. Each night it is recommended that:
    • Children aged 5 to 13 years get 9 to 11 hours of uninterrupted sleep.
    • Young people aged 14 to 17 years get 8 to 10 hours of uninterrupted sleep.
  • Good sleep hygiene practices can assist with falling asleep and getting an uninterrupted sleep. Encourage young people to follow these good sleep hygiene behaviours.
    • Maintain a consistent sleep schedule with a similar bedtime and wake-up time each day.
    • Limit screen time before bed e.g., from phones, laptops, TVs etc.
    • Avoid caffeine from the late afternoon onwards.

Recreational screen time

Evidence Base

This factsheet was developed following expert review by researchers at the Matilda Centre for Research in Mental Health and Substance Use including Senior Research Fellow Dr Katrina Champion. 

Page last reviewed: 30/08/2023

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