Self-guided Depression Treatment on Long-duration Space Flights: A Continuation Study

Objective: Depression could present a threat to the success and safety of long-duration space missions, and crews need the ability to manage it effectively. The primary objective of this study was to develop a self-guided interactive multimedia program that is capable of facilitating clinical improvement in persons with depression, when used in an entirely self-help format. Software developed through this study enables evidence-based treatment for depression to be made available to astronauts at any time in any location. It could be used autonomously or in combination with other medical resources.

(1) Original aims of the project:

1. Complete the development of a training module to recognize and prevent depression.

2. Develop a module to implement computer-based Problem-Solving Treatment (PST), an evidence-based treatment for depression.

3. Evaluate the efficacy of the computer-delivered PST module for depression in a randomized controlled trial.

(2) Key findings of the project: To address Aim 1, we produced a brief training video, in which Dr. Mark Hegel discusses the signs and symptoms of depression, how it can affect performance, and how it can be treated. A self-assessment of depression was created in a previous study, and already exists in the system. There is evidence from other studies that going through a course of PST can help prevent the future onset of depression in at-risk populations. Therefore, Aim 1 was addressed via the training video and the PST program, itself.

Addressing Aim 2 was the most challenging and time-consuming part of this project: designing and producing a fully-automated self-treatment program for depression. The end product was a 6-session interactive media program in which users are guided step-by-step through a full course of PST, an evidence-based treatment for depression. Each session involves a coach (Dr. Mark Hegel, a psychologist who is an expert in PST) who appears in numerous video and audio clips to help users/patients proceed through the stages of the treatment. The program was designed to exercise a form of "clinical judgment," by helping users/patients troubleshoot ways to improve their work on particular problems. The program also tracks 9 variables which are utilized to analyze the user's/patient's work across sessions and problems, and give suggestions on how to improve their problem-solving success, in general. This work has resulted in what appears to be the most sophisticated self-help program ever developed, in terms of media usage and data handling. It includes 247 audio and 160 video files to tailor the PST session to the individual.

Aim 3 was addressed via a randomized clinical trial pilot study, comparing the PST program to a 7-week waitlist control condition. We had originally planned to include 68 persons with minor depression in the study; however, the time required to complete development of the PST intervention program precluded enrolling this number. Therefore, we enrolled 14 persons in a pilot study (7 in the experimental group and 7 in the control group). The mean age of participants was 50 years, and all had completed at least 4 years of college, making them somewhat analogous to the astronaut population. The primary outcome was depression, as measured via the Hamilton Depression Inventory (HDI). No differences were found between groups on the HDI at pre-test.

We partnered with another NSBRI (National Space Biomedical Research Institute) study (PI: Dr. Gary Strangman), by sharing some participants. Participants were to be evaluated via magnetic resonance imaging (MRI) and near-infrared spectroscopy at 3 points: pre-treatment, mid-treatment (between sessions 3 and 4), and post-treatment. Unfortunately, MRI malfunctions and scheduling problems caused 2 of the 7 participants assigned to the experimental group to have a 4- and a 9-week lapse between sessions 3 and 4. Because our a-priori study procedures called for participants who lapse for more than 3 weeks between sessions to be removed from the study, data from these 2 participants were not included in the final analysis. We did, however, allow them to complete the final 3 sessions, since they wished to continue and had not caused the lapse of time. Also, one control group participant dropped out, leaving 6 in that group.

Percent change was compared using Kruskal-Wallis Chi Square at pre- and post-treatment for the experimental group and pre- and post- a no-treatment period of 7 weeks for the control group. A 52.65% reduction in depression was found for the 5 experimental group participants, whereas an 11.12% reduction was found for the control group. The difference in percent change was significant (p<.04), and an extremely high effect size was found (Cohen's d=1.73).

It is notable that if data from the 2 persons who lapsed longer than 2 weeks is included, the percent change is not significant, which suggests that if the treatment is used as recommended (i.e., with no more than a 3-week lapse between sessions), it is likely to help, but if not used as recommended, it is unlikely to help. It is also notable that no subjects ever "no-showed" for a scheduled PST session with the software.

(3) Impact of findings on specific aims of the original proposal. The specific aims were addressed, although the final number of participants enrolled was fewer than originally planned. The program shows strong promise as a new intervention, but requires further validation in a larger sample.

(4) Proposed research plan for coming year. We plan to apply for funding from other sources to conduct a large-scale randomized trial of the PST program's efficacy. We anticipate that these pilot data and the novelty of the treatment will provide strong support for such an application. If it is found to be efficacious in a larger trial, the program could be validated in a space analogue setting and ultimately used on long-duration missions. Additionally, it could provide an immediate public health benefit across the United States.

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