One in three intensive care survivors develop depression that typically manifests as physical symptoms

The study suggests that intensive care unit (ICU) survivors could be three times more likely to experience depression than the general population, and that depression is four times more common than post-traumatic stress disorder (PTSD) after critical illness.

"Considering that each year, at least 5 million individuals are admitted to ICU in North America alone -- more than are diagnosed with cancer -- and about 80% survive, it's a significant public health issue", explains study leader Dr James Jackson, psychologist and assistant professor of medicine at Vanderbilt University Medical Center in the USA.

"We need to pay more attention to preventing and treating the physical rather than psychological symptoms of depression in ICU survivors," says Dr Jackson. "The physical symptoms of depression are often resistant to standard treatment with antidepressant drugs and we need to determine how best to enhance recovery with a new focus on physical and occupational rehabilitation."

The Bringing to Light the Risk Factors And Incidence of Neuropsychological dysfunction in ICU survivors (BRAIN-ICU) study prospectively observed 821 critically ill patients with respiratory failure or severe sepsis (blood poisoning) admitted to medical or surgical ICUs in Nashville, USA. The researchers used a battery of neuropsychological tests to assess survivors at 3 months (448 participants) and 12 months (382) for depression, PTSD, functional disability, and impact on quality of life.

The researchers found that 149 of the 406 patients (37%) assessed at 3 months had at least mild depression -- two-thirds due largely to physical rather than psychological symptoms. A third of the survivors who developed depression still had depressive symptoms at their 12 month assessment.

While depressive symptoms were more likely to occur in patients with pre-existing depression, it was also found to be common in those without any psychiatric history, occurring in 76 of 255 patients (30%) at 3 months and 62 of 217 individuals (29%) at 12 months. In contrast, only 7% of patients experienced symptoms of PTSD.

The authors also noted that patients of all ages had high rates of disability in basic activities of daily living (eg, the inability to eat, bath, and dress without assistance) -- 32% at 3 months and 27% at 12 months. High rates of disability in instrumental activities of daily living (eg, the ability to manage money, make travel plans, make a complex shopping list, or follow a recipe) were also observed -- 26% at 3 months and 23% at 12 months. "These rates are worse than those seen in people with mild dementia", says Dr Jackson.

According to Dr Jackson, "Substantial time and energy has been invested in addressing PTSD in survivors of critical illness, but our findings suggest that it is less pervasive than depression. Patients of all ages are at risk of developing post-ICU mental health and functional disabilities and more needs to be done to ensure that these impairments don't become permanent."

Commenting on the study, Hallie C Prescott from the University of Michigan and Theodore J Iwashyna from the Center for Clinical Management Research, VA Ann Arbor Health System in the USA write, "These findings have important implications. When depression manifests as physical symptoms, patients are less likely to receive a diagnosis. If they are diagnosed, they are less likely to respond to treatment…Traditional pharmacological therapies for depression might be less likely to provide significant benefit alone (or at all). Instead, doctors might need to address the many diagnoses that contribute to poor sleep, impaired concentration, weakness, and fatigue."

They add, "By differentiation of depression into cognitive and physical components, Jackson and colleagues have provided an important step towards tailoring of future interventions to specific symptoms subsets, and not the generic diagnosis of depression."