Specific characteristics of the pain/depression association in the general population.

OBJECTIVE: To evaluate how the presence of a chronic painful physical condition (CPPC) lasting 6 months or more influences the frequency and severity of depressive symptoms in subjects with major depressive disorder (MDD).
METHOD: Random samples of 18,980 subjects aged between 15 and 100 years who were representative of the general population of 5 European countries (the United Kingdom, Germany, Italy, Portugal, and Spain) were interviewed by telephone between 1994 and 1999. Subjects answered a series of questions that allowed positive and differential diagnosis of DSM-IV mental disorders. The questionnaire also included a series of questions about painful physical conditions, medical treatment, consultations, and hospitalizations for medical conditions and a list of diseases.
RESULTS: A total of 4% (95% CI = 3.7% to 4.3%) of the sample had MDD at the time of the interview. Nearly half of subjects with MDD (43.4%) also reported having a CPPC. Compared with MDD subjects without chronic pain, MDD subjects with a CPPC had a longer duration of depressive symptoms (7 months longer) and were more likely to report severe fatigue (OR = 5.4), insomnia nearly every night (OR = 3.3), severe psychomotor retardation (OR = 3.3), weight gain (OR = 2.3), severe difficulty concentrating (OR = 1.7), and severe feelings of sadness or depressed mood (OR = 1.8).
CONCLUSION: A CPPC was present in nearly half of subjects with MDD. CPPCs increased the severity of physical symptoms of depression (fatigue, insomnia, psychomotor retardation, weight gain). Moreover, CPPCs affected the duration of depressive episodes and their recurrence. Physicians should consider CPPCs as a major factor in the expression and evolution of MDD. They must remember that MDD patients tend to amplify physical symptoms, to the detriment of their depressive symptomatology.