Sub-type Determines Sleep

Depressive disorder linked to sleep schedule

(RxWiki News) In everyday life it is easy to notice the differences between individual human beings. New research sheds light on the unique effects of depression between each individual.

A study available through the journal PLoS One examines the biological differences between variant subgroups of major depressive disorder patients. Findings conclude different endocrine and metabolic features occur in consequence to a woman’s sub-type of depression.

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Giovanni Cizza, M.D., Ph.D., an investigator for the National Institute of Health, led the study. Dr. Cizza and his fellow researchers discovered, “Pre-menopausal women with various features of major depressive disorder exhibit metabolic, endocrine, and bone mineral density features that may be associated with different health consequences.”

Patients with major depressive disorder tend to also be susceptible to cardiovascular disease and osteoporosis.  They often exhibit melancholic, atypical, or undifferentiated symptoms. 

Typical features associated with melancholic depression include numbness to pleasure, weight loss, insomnia, and guilt.

On the other hand, atypical depressive patients feel a bit more positive emotion and are able to rejoice in happy moments, while their symptoms follow opposite extremes, such as overeating or oversleeping.

Undifferentiated MDD patients do not fall into either of these categories. 

With this wide-range yet consistent set of typologies, study authors wondered whether clinical sub-types of depression also differentiate in their biological features and medical treatment outcomes.

Researchers analyzed bone turnover, the natural process of bone breakdown and reformation, in 133 pre-menopausal women (ages 21 to 45) either with major depressive disorder (MDD) or acting as healthy controls. The team studied the women’s metabolic features as well as body composition, bone mineral density, stress response, and circadian rhythm.

The study classified individuals into subgroups, with 51 patients with melancholic symptoms, 16 atypical, and 22 undifferentiated, classified using the Structured Clinical Interview for DSM-IV for Axis I Disorders.

Dr. Cizza and his team analyzed the medical variance amongst these subgroups, finding that women with undifferentiated or atypical symptoms of MDD showed significantly higher body mass index accompanied by higher proportions of fat mass.

Undifferentiated patients tolerated additional hardships with higher levels of fasting glucose and lipids—associated with diabetes—as well as a greater prevalence of low bone mineral density.

“In summary, we found that different clinical sub-types of depression were associated with specific bone, metabolic, and endocrine features,” Cizza concludes.

“Our findings lend support to the idea that depressive subtypes are not mere clinical entities but are rather distinct nosological entities,” or subgroups aiding in the classification of disease.

The future implications of this study may open the doors to further tailor treatment to the individual.

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Review Date: 
January 5, 2012