Hoyoung An

A Structural Model of Stress, Motivation, and Academic Performance in Medical Students

Objective The purpose of the present study was 1) to identify factors that may influence academic stress in medical students and 2) to investigate the causal relationships among these variables with path analysis. Methods One hundred sixty medical students participated in the present study. Psychological parameters were assessed with the Medical Stress Scale, Minnesota Multiphasic Personality Inventory, Hamilton Depression Scale, Beck Depression Inventory, and Academic Motivation Scale. Linear regression and path analysis were used to examine the relationships among variables. Results Significant correlations were noted between several factors and Medical Stress scores. Specifically, Hamilton Depression Scale scores (β=0.26, p=0.03) and amotivation (β=0.20, p=0.01) and extrinsically identified regulation (β=0.27, p<0.01) response categories on the Academic Motivation Scale had independent and significant influences on Medical Stress Scale scores. A path analysis model indicated that stress, motivation, and academic performance formed a triangular feedback loop. Moreover, depression was associated with both stress and motivation, and personality was associated with motivation. Conclusion The triangular feedback-loop structure in the present study indicated that actions that promote motivation benefit from interventions against stress and depression. Moreover, stress management increases motivation in students. Therefore, strategies designed to reduce academic pressures in medical students should consider these factors. Additional studies should focus on the relationship between motivation and depression.

Novelty-seeking and avoidant coping strategies are associated with academic stress in Korean medical students

High levels of stress and depression in medical students is raising concern. In this study, we sought to identify coping strategies and other factors influencing academic stress in medical students. We enrolled 157 students from the University of Ulsan College of Medicine, Korea, in November, 2010. We used the Medical Stress Scale, Temperament and Character Inventory, Hamilton Depression Scale, Beck Depression Inventory, and Coping Response Inventory to assess psychological parameters. We used Pearsons correlation and linear regression analyses to analyze the data. Novelty-seeking, self-directedness, cooperativeness, coping strategy, and depression scale scores all correlated significantly with stress level. Linear regression analysis indicated that students who are novelty-seeking, likely to use avoidant coping strategies, and unlikely to use active-cognitive and active-behavioral strategies tend to have higher stress levels. Reduction of stress in medical students may be achieved through evaluation of coping strategies and personality features and use of interventions to promote active coping strategies.

The impact of temperament and character on the efficacy of nonpharmacologic treatment of primary insomnia

Nonpharmacologic treatment, also known as cognitive behavioral treatment, is a first-line treatment of primary insomnia. We aimed to assess factors, including temperament and character, that were associated with responses to nonpharmacologic treatments of primary insomnia, that may assist physicians to recommend appropriate treatment. Outpatients diagnosed with psychophysiological insomnia (n = 99) were recruited between May 2009 and January 2010. Among 69 patients who consented to participate, 44 completed treatment and all assessment measures. In addition, 37 normal control subjects were also recruited. Baseline characteristics were assessed using the Temperament and Character Inventory, the Insomnia Severity Index, the Pittsburgh Sleep Quality Index, the Epworth Sleepiness Scale, the Dysfunctional Beliefs and Attitudes about Sleep scale, and the Hospital Anxiety and Depression Scale. After treatment, all assessment scales excluding the Temperament and Character Inventory were repeated. All patients received nonpharmacologic treatments, including sleep restriction, cognitive therapy, and sleep hygiene education. Novelty seeking, harm avoidance, reward dependence, cooperativeness, and self-transcendence scores were significantly different between normal controls and study subjects. Participants were divided into treatment responders (n = 23) and nonresponders (n = 21). Responders were significantly younger (50.3 ± 12.8 vs 58.7 ± 9.6 years, P = .02) and had significantly higher reward dependence scores (51.7 ± 5.9 vs 42.9 ± 6.9, P < .01) compared with nonresponders. The difference in reward dependence scores remained significant after controlling for other factors (odds ratio, 1.23; 95% confidence interval, 1.08-1.40; P = .01). Among personality dimensions, reward dependence was significantly associated with response to nonpharmacologic treatment in patients with primary insomnia.

A Case of Obstructive Sleep Apnea Syndrome Presenting as Paradoxical Insomnia

A 63-year-old female with obstructive sleep apnea syndrome (OSAS) presented with clinical features indistinguishable from paradoxical insomnia (PI). Her main complaint was chronic insomnia. Her subjective sleep latency was 2-3 h, subjective sleep time was less than 3 h, despite spending 8 h in bed, and she reported near constant awareness of her surroundings while lying in bed. Her body mass index (BMI) was 22.67 kg/m2, and her neck circumference was 34.5 cm. Nocturnal polysomnography (NPSG) findings indicated severe OSAS. Her total sleep time (TST) was 359 min, sleep latency 13 min, and her apnea/hypopnea index (AHI) was 74.6/h. The aim of this report is to evaluate the association between PI and OSAS cases confirmed by NPSG.

Orexin Impairs the Phagocytosis and Degradation of Amyloid-β Fibrils by Microglial Cells

BACKGROUND Intracranial accumulation of amyloid-β (Aβ) is a characteristic finding of Alzheimers disease (AD). It is thought to be the result of Aβ overproduction by neurons and impaired clearance by several systems, including degradation by microglia. Sleep disturbance is now considered a risk factor for AD, but studies focusing on how sleep modulates microglial handling of Aβ have been scarce. OBJECTIVE To determine whether phagocytosis and degradation of extracellular Aβ fibrils by BV2 microglial cells were impaired by treatment with orexin-A/B, a major modulator of the sleep-wake cycle, which may mimic sleep deprivation conditions. METHODS BV2 cells were treated with orexin and Aβ for various durations and phagocytic and autophagic processes for degradation of extracellular Aβ were examined. RESULTS After treatment with orexin, the formation of actin filaments around Aβ fibrils, which is needed for phagocytosis, was impaired, and phagocytosis regulating molecules such as PI3K, Akt, and p38-MAPK were downregulated in BV2 cells. Orexin also suppressed autophagic flux, through disruption of the autophagosome-lysosome fusion process, resulting in impaired Aβ degradation in BV2 cells. CONCLUSIONS Our results demonstrate that orexin can hinder clearance of Aβ through the suppression of phagocytosis and autophagic flux in microglia. This is a novel mechanism linking AD and sleep, and suggests that attenuated microglial function, due to sleep deprivation, may increase Aβ accumulation in the brain.

Phentermine, Sibutramine and Affective Disorders

A safe and effective way to control weight in patients with affective disorders is needed, and phentermine is a possible candidate. We performed a PubMed search of articles pertaining to phentermine, sibutramine, and affective disorders. We compared the studies of phentermine with those of sibutramine. The search yielded a small number of reports. Reports concerning phentermine and affective disorders reported that i) its potency in the central nervous system may be comparatively low, and ii) it may induce depression in some patients. We were unable to find more studies on the subject; thus, it is unclear presently whether phentermine use is safe in affective disorder patients. Reports regarding the association of sibutramine and affective disorders were slightly more abundant. A recent study that suggested that sibutramine may have deleterious effects in patients with a psychiatric history may provide a clue for future phentermine research. Three explanations are possible concerning the association between phentermine and affective disorders: i) phentermine, like sibutramine, may have a depression-inducing effect that affects a specific subgroup of patients, ii) phentermine may have a dose-dependent depression-inducing effect, or iii) phentermine may simply not be associated with depression. Large-scale studies with affective disorder patients focusing on these questions are needed to clarify this matter before investigation of its efficacy may be carried out and it can be used in patients with affective disorders.

Large intracranial volume accelerates conversion to dementia in males and APOE4 non-carriers with mild cognitive impairment.

BACKGROUND It is unclear how brain reserve interacts with gender and apolipoprotein E4 (APOE4) genotype, and how this influences the progression of Alzheimers disease (AD). The association between intracranial volume (ICV) and progression to AD in subjects with mild cognitive impairment (MCI), and differences according to gender and APOE4 genotype, was investigated. METHODS Data from subjects initially diagnosed with MCI and at least two visits were downloaded from the ADNI database. Those who progressed to AD were defined as converters. The longitudinal influence of ICV was determined by survival analysis. The time of conversion from MCI to AD was set as a fiducial point, as all converters would be at a similar disease stage then, and longitudinal trajectories of brain atrophy and cognitive decline around that point were compared using linear mixed models. RESULTS Large ICV increased the risk of conversion to AD in males (HR: 4.24, 95% confidence interval (CI): 1.17-15.40) and APOE4 non-carriers (HR: 10.00, 95% CI: 1.34-74.53), but not in females or APOE4 carriers. Cognitive decline and brain atrophy progressed at a faster rate in males with large ICV than in those with small ICV during the two years before and after the time of conversion. CONCLUSIONS Large ICV increased the risk of conversion to AD in males and APOE4 non-carriers with MCI. This may be due to its influence on disease trajectory, which shortens the duration of the MCI stage. A longitudinal model of progression trajectory is proposed.

Acute pontine infarction presenting with depressive mood only

A 65-year-old male patient presented to Chosun University hospital in Gwangju, South Korea, complaining of sudden mood swings for 4 days. He was bright and diligent before the visit. He had become suddenly curt, unfriendly and lethargic, and then 2 days after, had more progressive mood swings. Four days earlier, his usual bright and hard-working demeanor had suddenly been replaced with a curt and unfriendly attitude. He had a history of hypertension and type II diabetes for 10 years and 4 years, respectively. The patient did not drink or smoke. Brain magnetic resonance imaging, taken 4 days after symptom onset, showed a small lesion in the right pontine tegmentum. It showed high signal intensity in the diffusion weighted image and low signal intensity in the apparent diffusion coefficient image. These results suggested an acute cerebral infarction (Fig. 1a,b). High signal intensities were observed in the right corona radiate, and no abnormal findings were detected in other sites, such as the periventricular area, deep white matter and subcortical gray matter in T2-weighted images (Fig. 1c). Magnetic resonance angiography showed occlusion of the right proximal carotid artery and left proximal middle cerebral artery (Fig. 1d). The

Treatment response and duration of maintenance treatment with adjunctive antidepressants in bipolar depression: A retrospective chart review

Objective. The aim of this study was to investigate the treatment response and optimal maintenance period of antidepressants to minimize the risk of switching in bipolar depression in clinical practice. Methods. In a retrospective chart review, 78 bipolar patients, treated for a depressive episode by adding antidepressant to ongoing mood-stabilizing medications and had been followed for at least 6 months were identified. We determined recovery to euthymia and/or switching into mania during the 6-month follow-up period and estimated the time from antidepressant initiation to mood change. Results. Antidepressants treatment responses were classified into four groups. In one group, depression was sustained for 6 months despite continuous antidepressant treatment (poor-response group, 10.3%). In the second, abrupt switch into mania occurred during antidepressant treatment (acute-switch group, 19.2%). In the third, the depression improved to euthymia without manic switching (good-response group, 50%). In the fourth, the depression improved to euthymia but manic switching occurred during maintenance with antidepressants (delayed-switch group, 20.5%), and the mean duration of antidepressants maintenance was 54.6±38.9 days. Conclusions. Bipolar depression has heterogeneous treatment responses to adjunctive antidepressant. Antidepressants should be discontinued within 8 weeks after improvement to euthymia to minimize the risk of manic switching.