A new study published in the July 2013 issue of the Journal of Psychiatric Practice shows that a very high percentage of psychiatric inpatients suffers from vitamin D deficiency. The study, led by Melanie Ryland, MD, and Steven Verhulst, PhD, found that 75 percent of the patients in an Illinois community hospital\u2019s psychiatric ward had insufficient vitamin D in their systems. This new study is consistent with prior research showing a link between mental illness and low vitamin D. Between December 2010 and June 2011, the researchers reviewed the charts of 544 psychiatric patients admitted to the community hospital after each patient\u2019s stay had ended. They found that the average level of vitamin D in these patients was 22.3 nanograms per milliliter (ng\/mL) and that 75 percent of the patients had vitamin D levels below 30 ng\/mL. Anything lower than 30 ng\/mL is considered to be insufficient. This percentage of people with insufficient levels of vitamin D is higher than the percentage of the overall population that suffers from vitamin D insufficiency. Cause or Effect? Whenever connections like this are identified, the question becomes how the two elements relate to one another. Is there a cause and effect connection? And if so, which element is the cause, and which the effect? Dr. Ryland, lead author of the study, concluded that low levels of vitamin D are most likely an effect of long-term mental illness rather than a cause of mental illness. The fact that low vitamin D levels appear in so many different kinds of mental illness decreases the likelihood that vitamin deficiency is playing a major role in causing these illnesses to form. Dr. Ryland and her fellow researchers wrote that it seems more probable that vitamin D deficiency is the result of behaviors commonly seen in many forms of mental illness. Patients suffering from mental illness generally struggle with self-care. They tend to spend more time indoors and have poor nutrition. Sunlight and food are the primary ways that people acquire vitamin D, so these common behaviors could explain low levels of vitamin D in patients who exhibit them. Vitamin D and Health The research does not rule out the possibility that vitamin D insufficiency may play some causative role in the development of mental illness. The authors of the study encourage medical professionals to help maintain vitamin D levels in well patients, and to treat vitamin D insufficiencies in mentally ill patients. Too often, low vitamin D is not addressed in patients receiving care for a mental disorder. The vitamin deficiency is seen as a lesser problem\u2014if it is recognized at all\u2014and often ignored in favor of treating the more significant medical problem. The possibility, however unproven, that vitamin D has a causative role in mental illness, combined with its role in maintaining overall wellness in other ways, makes it worthy of attention. Vitamin D is particularly important in maintaining bone health. The vitamin helps prevent bone breakdown, and plays a critical role in bone growth and remodeling. Vitamin D also plays a part in cell growth, immune system response, inflammation reduction and neuromuscular function. Until further research is done that shows a definite causal role for vitamin D in mental illness, or strong evidence of therapeutic benefits for psychiatric patients, medical professionals will not begin prescribing vitamin D as a mental illness-specific treatment. At the same time, the importance of vitamin D for overall health means that psychiatric patients can and should be treated for deficiencies as any other patient would be. When patients are not getting enough vitamin D from the sun or their diet, levels can be raised quickly through supplements. During this study, the researchers found that only 63 percent of the patients with low levels of vitamin D were treated for the condition with supplements. Dr. Ryland and the authors of this study recommended that this failure be addressed, since treating vitamin D deficiency is easy and inexpensive.