The use of substances of addiction has been on the rise in Australia. from 2016-2019, increases were seen in the use of addictive substances such as:
- cannabis (from 10.4% to 11.6%)
- cocaine (from 2.5% to 4.2%)
- ecstasy (from 2.2% to 3.0%)
- hallucinogens (from 1.0% to 1.6%)
- ketamine (from 0.4% to 0.9%) (Figure 1) (AIHW 2020).
Other substances, such as caffeine are consumed by approximately 9/10 Australians (88%). The consequence of this is long-lasting changes in brain neurochemistry and anatomy, due to the hijacking of the brains reward system, causing increased levels of dopamine in the nucleus accumbens, a key region for reward neurocircuitry in the brain. In sleep, the most common drugs of addiction (alcohol, opioids, cannabis, caffeine) significantly effect sleep latency, quality and duration. Alcohol has been shown to initially act as a sedative (reduced sleep latency), though effects slow wave sleep, REM latency + reduced REM sleep in first half of night and exacerbates OSA. Caffeine, an adenosine antagonist, leads to attenuated sleep pressure and worsening sleep quality due to increased pituitary gland action (dilated pupils, vasoconstriction, increased heart rate). Opioids affect processes in the locus coeruleus, which control the release of noradrenaline (reduced respiratory drive, muscle tone, wakefulness). This can cause reduced REM sleep, poor sleep quality & an exacerbation of sleep-disordered breathing. Finally, cannabis has been shown to have both both beneficial & adverse effects on low doses of CBD oil or THC oil. There seems to be some short-term benefit to cannabis, however long term use can lead to acute bronchitis, chronic coughing, wheezing, reduced sleep efficiency, reduced SWS and increased sleep latency.
