Why Can't I Sleep? The Most Common Causes of Insomnia
Reviewed by the Kamagra AUS Pharmacy Team on 19 November 2025 · Next review June 2027
Summary
Insomnia has a genuinely wide range of possible causes — stress, habits, physical conditions, medicines and more — which is why 'just take a sleeping tablet' is rarely the complete answer.
On this page
Insomnia is difficulty falling asleep, staying asleep, or waking too early and not being able to get back to sleep, and it has a genuinely wide range of possible causes — which is exactly why "just take a sleeping tablet" is rarely the complete answer.
Stress and an overactive mind
Stress, anxiety and an active mind at bedtime are among the most common contributors to short-term insomnia. A racing mind reviewing the day's events, tomorrow's tasks, or a specific worry is a very ordinary experience, and for many people it resolves as the underlying stressor eases.
Poor sleep habits (sleep hygiene)
Irregular sleep and wake times, screens right before bed, caffeine later in the day, and an inconsistent bedtime routine can all independently make falling and staying asleep harder — and these habits can compound with other causes, making an existing sleep problem worse than it needs to be.
Physical health conditions
A number of physical conditions disrupt sleep directly: pain of any kind, an overactive bladder or the need to urinate frequently overnight, hormonal changes, and breathing-related issues like sleep apnea (see our guide on snoring vs sleep apnea) can all fragment sleep even when the mind is calm.
Mental health conditions
Depression and anxiety disorders have a well-documented, bidirectional relationship with sleep — poor sleep can worsen mood, and mood conditions can worsen sleep, which is one reason ongoing insomnia is worth mentioning to a doctor rather than treating in isolation.
Medicines and substances
Some prescription medicines, along with caffeine, nicotine, alcohol (which can help you fall asleep but fragments sleep later in the night) and recreational substances, can all interfere with normal sleep architecture.
Where medicine like zopiclone fits in
Zopiclone and other sleep aids are generally intended for short-term use while the underlying cause is identified and addressed, rather than as a standalone long-term fix — because if the actual driver isn't dealt with, the sleep problem tends to persist once the medicine stops. A doctor can help work out which of the causes above is most likely driving your specific insomnia.
This article is general information, not medical advice. If insomnia is persistent or significantly affecting your daily life, speak with a doctor to identify the underlying cause and the most appropriate approach.
Frequently asked questions
What's the most common cause of short-term insomnia?+
Stress and an overactive mind at bedtime are among the most common contributors to short-term insomnia, though poor sleep habits and physical health conditions are also frequent causes.
Can insomnia be caused by a physical health condition?+
Yes — pain, an overactive bladder, hormonal changes and breathing-related conditions like sleep apnea can all disrupt sleep, sometimes even when stress isn't a major factor.
Is it fine to rely on sleep medicine long-term?+
Sleep medicines like zopiclone are generally intended for short-term use while the underlying cause is identified, since the sleep problem often returns once the medicine stops if the actual cause isn't addressed. Speak with a doctor about a longer-term approach.
When should insomnia be checked by a doctor?+
If it's persistent, significantly affecting your daily functioning, or you suspect an underlying physical or mental health cause, it's worth a doctor's assessment rather than managing it indefinitely on your own.
Kamagra AUS Health Editorial Team
Plain-English health writing from our in-house editorial team — sourced to the TGA, healthdirect and each medicine's product information, and focused on how Australians actually access and use medicines safely.
How our content is written & reviewedSources for the medical information in this guide
- Sleep Health Foundation — Australian sleep-health charity — search the topic for evidence-based guidance on insomnia and sleep disorders.
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