Impact of major depressive disorder, distinct subtypes, and symptom severity on lifestyle in the BiDirect Study.

The aim of this study was to examine associations of major depressive disorder (MDD), its distinct subtypes, and symptom severity with the individual lifestyle factors smoking, diet quality, physical activity, and body mass index as well as with a combined lifestyle index measuring the co-occurrence of these lifestyle factors. A sample of 823 patients with MDD and 597 non-depressed controls was examined. The psychiatric assessment was based on a clinical interview including the Mini International Neuropsychiatric Interview and the Hamilton Depression Rating Scale. Each lifestyle factor was scored as either healthy or unhealthy, and the number of unhealthy lifestyle factors was added up in a combined lifestyle index. Cross-sectional analyses were performed using alternating logistic regression and ordinal logistic regression, adjusted for socio-demographic characteristics. After adjustment, MDD was significantly associated with smoking, low physical activity, and overweight. Likewise, MDD was significantly related to the overall lifestyle index. When stratifying for subtypes, all subtypes showed higher odds for an overall unhealthier lifestyle than controls, but the associations with the individual lifestyle factors were partly different. Symptom severity was associated with the lifestyle index in a dose-response manner. In conclusion, patients with MDD represent an important target group for lifestyle interventions.

Association between major depressive disorder and odor identification impairment.

BACKGROUND: There is evidence of olfactory deficits in patients with major depressive disorder (MDD) but causes and mechanisms are largely unknown. METHODS: We compared 728 patients with current MDD and 555 non-depressed controls regarding odor identification impairment taking into account the severity of acute symptoms and of the disease course. We assessed current symptom severity with the Hamilton Depression Rating Scale, and disease course severity based on admission diagnosis (ICD-10, F32/F33) and self-reported hospitalization frequency, defined as infrequent (<2) and frequent (≥2) depression-related hospitalizations under constant disease duration. A score of <10 on the Sniffin' Sticks-Screen-12 test determined the presence of odor identification impairment. RESULTS: Compared to non-depressed controls patients with frequent (rapidly recurring) hospitalizations had an elevated chance of odor identification impairment, even after adjustment for smell-influencing factors, such as age and smoking, (OR=1.7; 95% CI 1.0-2.9). Patients with recurrent MDD (F33) also had an elevated odds of odor identification impairment compared to those with a first-time episode (F32, OR=1.5; 95% CI 1.0-2.4). In patients with a first-time episode the chance of odor identification impairment increased by 7% with each point increase in the Hamilton Score. LIMITATIONS: Cross-sectional study. Variation in the use of psychotropic medication is a potential bias. CONCLUSION: Odor identification impairment was evident in MDD patients with first-time high symptom severity and in patients with a severe disease course. Whether odor identification impairment is a marker or mediator of structural and functional brain changes associated with acute or active MDD requires further investigations in longitudinal studies.