Where several different objects produce the same effect, it must be by means of some quality, which we discover to be common amongst them. For as like effects imply like causes, we must always ascribe the causation to the circumstance, wherein we discover the resemblance. David Hume, A Treatise of Human Nature The present findings suggest that even if everyone was treated in the best possible fashion, about 60% of the burden of mental disorders appears to be unavertable in the light of current knowledge…even with perfect coverage and treatment, half the burden of anxiety disorders would remain unavertable. Andrews G, Issakidis C, Sanderson K, Corry J, Lapsley H: Utilising survey data to inform public policy: comparison of the cost-effectiveness of treatment of ten mental disorders. Br J Psychiatry 2004; 184:526–533

Bacterial infections are associated with many autoimmune diseases involving chronic inflammation and demyelination. The possible mechanisms of bacterial involvement as aetiological agents or in the exacerbation of these diseases have been investigated intensively. This review focuses the role of bacterial infections in the pathogenesis of autoimmune, inflammatory and demyelinating diseases. Possible modes of pathogenic action of bacteria are discussed, viz. the role of cytokines, Toll-like receptor signaling, the interaction of heat shock proteins with the immune system, and the role of nitric oxide. An auto-regulatory loop might exist in the interaction of bacteria with the host and in pathogenic signal processing. These studies reveal potential therapeutic targets. Abbreviations: AQP4 Aquaporin-4; AS ankylosing spondylitis; CSF cerebrospinal fluid; EAE autoimmune encephalomyelitis; GB Guillain-Barre syndrome; HLA human leukocyte antigens; HSP heat shock protein; IL interleukin; LPS lipopolysaccharides; MAM Mycoplasma arthritidis antigen; MHC [proteins encoded by] major histocompatibility gene complex; MS multiple sclerosis; NK natural killer cells; NMO neuromyelitis optica; NO nitric oxide; NOS nitirc oxide synthase; PCR polymerase chain reaction; RA rheumatoid arthritis; SLE systemic lupus erythematosus; TLR Toll-like receptors; TNF tumour necrosis factor.

Over the last several decades, our understanding of the causes of low back pain has been challenged. With a sensitivity up to 95%3, MRI has been used a gold standard for the diagnosis of spine disease such as lumbar disc herniation. With the “MRI evidence” of a disc herniation and nerve root compression, patients are more easily convinced surgery is their best and only option. However, the reliability of MRI as the evidence for surgical decision has been questioned. An early study found that in a group of asymptomatic volunteers at age of 60 years or older, about 57% had abnormal MRI findings including disc herniation and spinal stenosis4. Follow up studies have yielded similar results. Now it is widely accepted that degenerative disc disease, such as disc herniation is a common finding in asymptomatic adults. Even though at the age of 60 years or older, 57% or more may have abnormal MRI findings in the lumbar spine, however, only less than 20% of this group of people have chronic low back pain. A recent study also suggested a lack of correlation between imaging findings of spine degenerative change and back pain5. Simply, degenerative change in the lumbar spine, such as a herniated disc, is not necessarily painful.