Placebo effects factors affecting

One of the factors that determine the effectiveness of a placebo is the nature of the condition being treated. Conditions that have a strong psychological component - such as pain, anxiety and depression - are particularly prone to placebo influence, whereas conditions like bone fractures, diabetes and infertility are less likely to be affected by placebo treatment. But this does not mean that placebo effects are all in the mind . Placebos affect physiology as well as psychology. 

The evidence I have reviewed in this chapter indicates that placebos work for a wide variety of conditions. They can produce both positive and negative effects. They affect the body as well as the mind. They can be as strong as potent medications, and their effects can be lasting. We have also seen that placebos can produce negative effects. Furthermore, the nocebo effect maybe an important factor in clinical depression - at least for some depressed people. For this reason, understanding the placebo effect is essential to understanding how to treat depression effectively. How do inert substances produce both therapeutic and detrimental effects Chapter 6 provides an answer to this question. 

Erectile impotence is particularly common in men with diabetes (16), who are likely to have difficulties because of autonomic dysfunction. It is unclear whether younger men and women are similarly affected and whether nor-motensive men have fewer such problems (124). Most investigations of the effects of diuretics on sexual function have been characterized by poor study design (125) the majority had no placebo control and relied on comparisons with baseline. The best studies have suggested an increase in erectile dysfunction in thiazides users compared with placebo. Bearing in mind all the confounding factors, it can be concluded that diuretics will sometimes cause impotence, but that in the population as a whole the effect is slight compared with other causes (SEDA-11, 197) (SEDA-11,198). 

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