This study investigated whether the resilience of males with probable bipolar depression (PBD) can be strengthened and compared it to that of males with probable unipolar depression (PUD).
Prospective data for 198 participants (PBD: 66, PUD: 66, normal control: 66) were analyzed. The participants' resilience, bipolarity and severity of depressive symptoms were evaluated at baseline and after 5 weeks. Analysis of variance (ANOVA) and repeated measure ANOVA was performed for comparing resilience between three groups through a basic military training.
The PBD group demonstrated more resilience than the PUD group at baseline. Participants with PBD became significantly more resilient than participants with PUD after 5 weeks (p<0.01, F=6.967, η2p=0.052).
The study indicates that interventions that strengthen resilience need to be developed for males with PBD and that such interventions are more effective for males with PBD than PUD.
Resilience has been defined as an individual's ability to more effectively cope with stress and adapt in the face of adversity or trauma than other individuals.
Over the past several years, training programs aimed at promoting resilience have been developed. A recent study on the US army suggested that such programs could improve resilience.
In several countries, young healthy males are required to serve in the military, typically beginning in late adolescence to early adulthood. Conscripts could experience reduced stress levels, as a positive psychological reward, after successfully completing basic military training.
Previous studies have not sufficiently explained how resilience can be altered. Especially, it is not known whether the alternation of resilience is different among people with other mood disorders. Previous studies suggested the positive aspects of individuals with bipolar disorder, such as positive response in life stress, and lower risk for posttraumatic stress disorder (PTSD) in patients with history which had overcome the PTSD than in patients without a history of PTSD.
The aim of this study was to investigate whether the resilience of males with probable bipolar depression (PBD) can be strengthened and to compare it with that of males with probable unipolar depression throughout basic military training after controlling for depressive symptoms.
This study examined Korean conscripts admitted to a basic military training camp in 2015. The absence of marked medical and psychiatric diseases among subjects was confirmed through the national draft examination. Conscripts were informed of the survey and methods and signed written consent forms before beginning their training. Basic military training in Korea consists of the content, including regular basic physical training, mental training, religious activities, military manners and basic military skills training, for 5 weeks. This study was prospectively designed, and the survey was administered before the start of basic training and repeated 5 weeks later. At baseline, participants completed self-report questionnaires, including a survey of socio-demographic characteristics, the Connors-Davidson Resilience Scale (CDRISC), the Korean version of Mood Disorder Questionnaire (K-MDQ), the Center for Epidemiological Studies-Depression Scale (CES-D), and the Barratt Impulsiveness Scale-11-Revised (BIS-11-R). After 5 weeks, participants completed self-report questionnaires, including the CDRISC and CES-D. A total of 227 subjects participated in this study, and the data of 198 participants were analyzed. This study was approved by the Clinical Medical Research Ethics Committee of the Korean Armed Forces Medical Command.
The CDRISC is a measure used to assess resilience. Connor and Davidson developed the scale, which consists of 25 items, in 2003.
The MDQ is a self-report scale that screens for lifetime bipolar disorder. It comprises 3 sections and consists of 15 items. The K-MDQ was translated and validated in 2009.
The CES-D is a self-report scale that assesses depressive symptoms in the past 1 week. This scale consists of twenty questions that are rating on a four-point Likert scale ranging from 0 (rarely or none of the time) to 3 (most or all of the time). The Korean version of the CES-D was translated and validated in 1998 in a test of the general population. A cutoff value of 16 or higher indicates clinical significance in the screening of depression.
The BIS-11-R was used to evaluate trait impulsivity.
The sample (n=227) was divided into three groups according to the following criteria: PBD group (n=77): greater than 16 points on the CES-D and greater than 7 points on the K-MDQ; PUD group (n=66): greater than 16 points on the CES-D and less than 7 points on the K-MDQ; Normal Control group (NC; n=84): less than 16 points on the CES-D and less than 7 points on the K-MDQ. The NC and PBD groups were matched to the PUD group on age, education level, and BIS-11-R scores using propensity score matching analysis. High levels of trait impulsivity reciprocally affect low levels of resilience among people with bipolar disorder.
All participants were male. The mean age, education level and BIS-11-R scores did not significantly differ across groups (
This study investigated whether the resilience of males with PBD would be strengthened following the basic military training. To the best of our knowledge, the present study is the first to identify that basic military training could strengthen the resilience of males with PBD. The main findings of this study were that males with PBD had greater resilience than males with PUD at baseline, and that of males with PBD was more strengthened than that of males with PUD and that the former group experienced euthymia after military training. The effect size was moderate. Differences in resilience between those with PBD and PUD may be related to affective temperament or character traits.
Resilience was defined as positive adaptation to adversities and difficulties.
Individuals with an affective temperament or character traits such as hyperthymic temperament, extroversion and high sociability have more characteristics that protect against stress.
Differences in neurocognition might inform differences in the strengthening of the resilience of people with PBD and PUD. Patients with bipolar disorder display greater ventral striatal activation and reduced activation in the dorsolateral prefrontal cortex, explaining their preference for immediate gratification over achieving long-term goals.
This study has several limitations. First, because self-report questionnaires were used to screen for bipolar disorder in this study, participants had only PBD rather than diagnosed bipolar disorder. Therefore, the results of the present study cannot be generalized to people with bipolar disorder. However, the MDQ has good sensitivity for bipolar disorder, and previous studies suggested that subjects scoring above the cut-off value had PBD or bipolarity.
Despite these limitations, this study was the first to prospectively investigate the positive aspect of strengthening the resilience of males with PBD and to comparing it with that of males with PUD. Temperaments, characteristics and neurocognitions, which people with PBD is a more resilience than PUB, might have more improved resilience on males with PBD than PUD, after the training. The resilience of people with PBD could be more strengthened than that of people with PUD exposed to the same environment after training even after confounding factors such as impulsivity, age and level of education are controlled. Resilience is associated with prognosis, including number of depressive episodes and quality of life on psychiatry.
This work was supported by the Korean Military Medical Research Project funded by the ROK Ministry of National Defense (ROK-MND-2015-KMMRP-02).
*mean±SD, †N (%), ‡Fisher's exact test was done. PBD: Probable Bipolar Disorder, PUD: Probable Unipolar Depression, NC: normal control, BIS-11-R: the Barratt Impulsiveness Scale-11-Revised
*p<0.01, †the interaction of group and time, ‡Greenhouse-Geisser, §Covariate: CES-D scores at baseline. PBD: Probable Bipolar Disorder, PUD: Probable Unipolar Depression, NC: normal control, CDRISC: Connors-Davidson Resilience Scale, CES-D: Center for Epidemiological Studies-Depression scale