Sleep reactivity predicts insomnia in patients diagnosed with breast cancer

Study Objectives: To examine the role of sleep reactivity as a predictor of insomnia in patients diagnosed with breast cancer.
Methods: One hundred and seventy three women with breast cancer participated and were followed up over a period of 9 months. At baseline participants were assigned to a high (n=114) or low (n=59) sleep reactivity group, based on their responses to the Ford Insomnia Response to Stress Test (FIRST). We assessed whether these FIRST groupings (high/low sleep reactivity) predicted changes in insomnia over time using the Insomnia Severity Index (ISI). We also tested if these FIRST groupings predicted insomnia disorder (using ISI index cut-offs) at three different time points (T3, T6 and T9).
Results: Individuals with high sleep reactivity were more likely to experience a worsening of insomnia. Using logistic regression we also found that FIRST grouping predicted insomnia disorder. Results remained significant after controlling for estimated pre-morbid sleep, age and whether someone had chemotherapy.
Conclusions: Our study shows that sleep reactivity may be a robust predictor of insomnia within breast cancer populations. Sleep reactivity should be considered in routine clinical assessments as a reliable way to identify patients at risk of developing insomnia. This would facilitate early sleep intervention for those patients who are considered high risk.