Johnny Pellas: Assessment and psychological treatment of depression in older adults

Abstract

Depression is one of the leading causes of disability in older adults worldwide. Many older adults with depression are undetected, and there is a need for brief, scalable psychological treatments for depression that can be delivered remotely.

The aims of this thesis were 1) to investigate the diagnostic accuracy of two rating scales (PHQ-9 and GDS-15) for the detection of depression in older adults, and 2) to investigate the feasibility, preliminary efficacy and patients’ experiences of a telephone-based psychological intervention, Behavioral activation with mental imagery (BA-MI), for the treatment of depression in older adults in the context of the covid-19 pandemic. 

Study I showed that a cutoff of ≥6 on the GDS-15 and ≥5 on the PHQ-9 were optimal to identify major depressive disorder. When identifying both major depressive disorder and subthreshold depression, the optimal cutoff on the GDS-15 was ≥5. Study II was a randomized clinical pilot trial, CoviDep, with a treatment group receiving the BA-MI intervention, and a control group. The drop-out rate was low. Compared to the control group, the treatment group reported a decrease in depressive symptoms throughout the treatment, with a large effect-size at posttreatment. Study III was a long-term follow-up of participants in CoviDep that received the BA-MI intervention. The drop-out rate over time was low, and compared to baseline, decreases in depressive symptoms were observed with a medium effect-size at posttreatment that was maintained 1- and 3 months post-treatment but lower after 6 months. Study IV was a qualitative study. The BA-MI intervention in CoviDep was described as increasing activities and improving mood. Telephone-delivery reduced barriers due to pandemic restrictions but felt less personal and lacking non-verbal communication. Being recognized and talking to a therapist every week was healing, but the manualized mode of treatment seemed to impair the relationship.

In sum, this thesis shows that both the GDS-15 and the PHQ-9 are useful tools for the detection of depression in older adults, and adds to the support for telephone-delivered BA for the treatment of depression and indicates that MI-interventions are feasible as an augmentation of BA in older adults.