Researchers have found treating insomnia can also help reduce symptoms of depression, with participants in a new study reporting improvements in both conditions.

Led by Vanika Lall, Clinical Associate Professor Melissa Ree and Emeritus Professor Romola Bucks, from The University of Western Australia’s School of Psychological Science, the study published in Behaviour Research and Therapy found insomnia therapy may hold the key to lasting depression recovery.

“As many as nine in 10 people with depression also have disturbed sleep,” Ms Lall said. “Insomnia can make depression worse or last longer and also blunt people’s response to depression treatment.

“Leaving insomnia untreated increases the risk of depression returning and while depression treatments can help improve insomnia, they are usually not completely effective.”

The Sleep Well for Mood study recruited people experiencing both depression and poor sleep to receive cognitive behavioural therapy for insomnia (CBT-I) – a structured, short-term treatment known to improve sleep by addressing unhelpful thoughts and behaviours, often combining cognitive therapy, behavioural strategies and sleep education.

The study collected data from 88 participants enrolled in a four-week CBT‑I program who were assessed before treatment, after treatment and at three‑month follow‑up.

After the treatment, individuals showed improvements in insomnia symptoms and also reported engaging in less negative thinking about day-to-day issues, having fewer worries about sleep and spending more time participating in meaningful activities, such as physical and social activities.

“Negative thinking and an inactive lifestyle fuel depression,” Ms Lall said. “Our results suggest CBT‑I is a time- and cost-effective way to treat insomnia and depression together as it improves core drivers of depression within real-world settings.”

The results suggest a greater uptake of CBT‑I could transform depression care, helping more people achieve long-term recovery while easing the burden of recurring depression on our healthcare system.