This study demonstrated that item 3 of the PHQ-9 is a potentially effective screener to identify sleep disturbance in VA primary care settings. Specifically, our results show that a cut score of 1 on the PHQ item-3 (indicating sleep problems several days in the last 2 weeks) provides the best balance of sensitivity and specificity, such that 82.5% of patients with sleep disturbance were correctly identified while 84.5% of patients without sleep difficulty were correctly ruled out using the PHQ item-3.
These results are particularly promising given the current recommended use of the PHQ-9 in primary care settings.26
The implication of these results is that PCPs may screen for sleep disturbances without implementing a separate, sleep-specific measure. Instead, should a patient endorse a 1 or higher on item 3 on the PHQ-9, it could signal to the provider to further assess the patient’s sleep and intervene if necessary. Sleep interventions are effective in both improving sleep in primary insomnia patients,3,13,45
as well as in patients who are experiencing insomnia and other sleep disturbances comorbid with other disorders.46–50
Furthermore, preliminary studies suggest that improving sleep quality may also improve symptoms of other physical and mental health disorders associated with insomnia,51–53
further emphasizing the importance of identifying and treating this, and potentially other common sleep disturbances.
It is of note that while the ISI has been found to adequately assess the diagnostic criteria for insomnia,27
it does not provide a valid diagnosis for insomnia or any other sleep problem. Additionally, the established ISI cutoff score of 8 includes insomnia symptoms that may be considered ‘mild’ or subthreshold.27
However, it was important to capture those patients with mild/subthreshold sleep problems with the ISI to test the PHQ item-3’s efficacy at identifying patients with subthreshold symptoms as well as a potential sleep disorder. The PHQ item-3 performed well in this capacity, as evidenced by its high level of sensitivity (82.5%), which is particularly important in a screening measure.54
Although this study is an important first step in the validation of the PHQ item-3 as an effective screening tool in primary care, our results should be interpreted in the context of some important limitations. Our sample consisted of male veterans from two Upstate New York VA clinics, where the majority of the sample was between 44 and 78 years of age, and drank regularly, which could reduce the generalizability of our findings. Future work in this area should include studies conducted in non-VA primary care clinics, in samples diverse enough to address generalizability across gender, age, race, and health care settings. Future studies should also include both drinkers and non-drinkers given the known relationship between alcohol and sleep.55
An additional important limitation is that PHQ item-3 assesses both insomnia and hypersomnia and we only validated it against an insomnia instrument. It remains to be seen to what extent false positives are related to endorsing the PHQ sleep item due to hypersomnia and whether these may represent true cases of hypersomnia requiring treatment. The latter is particularly important given that the most common sleep disorder with hypersomnia as a feature, sleep apnea, is a significant concern in primary care and associated with multiple health risks.56–58
If the PHQ item performs reasonably well in detecting cases of sleep apnea, it could prove to be a very efficient tool for identifying the two most common forms of sleep disorders (insomnia and sleep apnea).
Though not the focus of the paper, the significant negative relationship between age and sleep in this sample warrants further discussion. This finding is in contrast with a wealth of literature stating that, as people age, their sleep worsens.42,43
Alcohol intake did not account for this relationship in this sample, which is unexpected, given the close relationship between alcohol and sleep,55
and the fact that most people in our sample were regular drinkers. Rather, our post hoc analyses revealed that, once PTSD symptoms were added to the regression model, the significant relationship between age and sleep went away. This finding is not surprising given the significant correlation between PTSD symptoms and age in our sample and the literature demonstrating that PTSD symptoms disrupt normal sleep 44
Overall, this study is an important first step in the validation of the PHQ item-3 as an effective sleep screen for primary care. The PHQ item-3 is brief, and does not require an additional screen to primary care providers, who are already burdened with many annual screens. Particularly in settings already using the PHQ-9, this can be an incredibly efficient use of resources. Pulling out and focusing on the PHQ item-3 could help providers to more readily identify insomnia and potentially other sleep disturbances in their patients. Ultimately, identifying sleep disturbance is the gateway to interventions with demonstrated efficacy and to the common goal of improving their overall health and quality of life.