Hypochondriasis is an excessive preoccupation or worry about having a serious illness that persists even after a doctor has examined a patient and told them that they have nothing to worry about. It is thought to affect around 3% of the population and is often characterized by fears that minor bodily symptoms may indicate a serious illness, constant self-examination and self-diagnosis and a preoccupation with ones body. Cognitive-behavioural treatments (CBT) have been shown to be effective in treating hypochondriasis and so has CBT-based, short-term psycho-educational group treatment. A Dutch study of 140 people with health anxiety looked at how different people benefited, or failed to benefit from CBT. The study found that participants with high scores for health anxiety at the start of the study tended to continue to have high scores after treatment and at follow-up tests one and six months later. People with higher "background" levels of anxiety and who were older benefited least from CBT treatment.
Buwalde, Femke M. and Bouman, Theo K. - Predicting the effect of psychoeducational group treatment for hypochondriasis Clinical Psychology and Psychotherapy, December 2008, 15(6), 396-403