The Big Picture on Depression
Kelly M. Goedert, Seton Hall University
Susan A. Nolan, Seton Hall University
Kaylise D. Algrim, Seton Hall University
Depression can be an isolating condition, but it is also a widespread disorder, affecting 350 million people worldwide. On an individual level, people experience depression differently, but some researchers hoped that looking at depression in a large sample could help clinicians to see its patterns more clearly. A study used the National Survey of Midlife Development (MIDUS) to assess the patterns of depression symptoms in a group of 6223 Americans (Tomitaka et al., 2017). The survey included a standard depression measure, the Kessler Screening Scale for Psychological Distress (K6), which was completed by a representative sample of U.S. adults, ages 25–74. The K6, as its name implies, includes six items that are associated with depression. For each item, survey respondents were asked to indicate how often they felt that way over the past month on a scale of 0 to 4.
On the K6, higher numbers contribute to a higher overall depression score. Let’s get a sense of what contributes to a high depression score.
Participants in the study completed the K6, rating how often they felt each of the six depression-related emotions in the last 30 days. The researchers then summed those scores to create a total score for each participant. Based on the 0–4 scale for each item, the total scores could range from 0 to 24. The graph here shows the histogram for the total scores.
Here’s the same histogram from the previous screen, which shows the frequency for each total score on the K6.
Another option for displaying data is a grouped frequency table, which uses intervals to show data within certain ranges. This is helpful for large data sets or for scores with decimal places.
As we noted previously, these data are positively skewed.
|Symptom||The number and, in parentheses, percentage of the 6,223 participants who gave each rating.|
|Everything was an effort||3632 (58.4)||1664 (26.7)||637 (10.2)||214 (3.4)||76 (1.2)|
|Restless or fidgety||2951 (47.4)||2042 (32.8)||997 (16.0)||184 (3.0)||49 (0.8)|
|Nervous||2718 (43.7)||2253 (36.2)||1011 (16.2)||199 (3.2)||42 (0.7)|
|Worthless||5004 (80.4)||765 (12.3)||326 (5.2)||89 (1.4)||39 (0.6)|
|Hopeless||5000 (80.3)||768 (12.3)||330 (5.3)||91 (1.5)||34 (0.5)|
|Sad||4383 (70.4)||1260 (20.2)||462 (7.4)||97 (1.6)||21 (0.3)|
This shows the number of participants who endorsed each rating choice for each of the six symptoms, as well as the percentage of all participants who endorsed each rating choice.
The bottom line: Expanding our scope helps us to understand the details more clearly. So when trying to understand depression, it can help to take a step back and look at the big picture.
Tomitaka, S., Kawasaki, Y., Ide, K., Akutagawa, M., Yamada, H., Ono, Y., & Furukawa, T. A. (2017). Characteristic distribution of the total and individual item scores on the Kessler Screening Scale for Psychological Distress (K6) in US adults. BMC Psychiatry, 17 (1). https://doi.org/10.1186/s12888-017-1449-1