TEMPORAL RELATIONSHIPS BETWEEN PHYSICAL SYMPTOMS AND PSYCHIATRIC-DISORDER - RESULTS FROM A NATIONAL BIRTH COHORT

Background Physical symptoms and psychiatric disorder are associated. We aimed to investigate which comes first. Methods Data from the Medic al Research Council National Survey of Health and Development, a popul ation-based birth cohort study were used at two time points: 36 and 43 years. Six physical symptoms were reported at both time points. The P resent State: Examination and Psychiatric Symptom Frequency interviews were administered at 36 and 43 years respectively. Odds ratios correc ted for a variety of confounders were used to describe the association s between physical symptoms and psychiatric disorder across these two time points. Results Psychiatric disorder increased the odds of report ing symptoms 3-7-fold. The relationship strengthened when the outcome was defined as suffering from multiple symptoms. Population attributab le risk of psychiatric disorder and subsyndromal disorder in causing m ultiple somatic symptoms was 40.3%. Prospectively, psychiatric disorde r at 36 years was a predictor for five of the six physical symptoms. T hree physical symptoms at 36 years predicted new onset of psychiatric symptoms at 43 years. Conclusions Psychiatric disorder is strongly rel ated to physical symptoms. The direction of causality may operate in b oth directions. Assuming a causal relationship, psychiatric disorder ( including subthreshold disorders) could account for at most 40% of cas es of multiple physical symptoms.