Diagnostic conversion from depression to bipolar disorders: results of a long-term prospective study of hospital admissions.
ABSTRACT To analyse the time course and some risk factors for a diagnostic change from major depression to bipolar disorders (BP) over an average of 20 years from the onset of the disorders.
Patients (406) with major mood disorders hospitalised at some time between 1959 and 1963 were followed-up until 1985. The analysis also included the course prior to hospitalisation. Survival analyses and Cox regression models were applied.
A diagnostic change from depression to bipolar I occurred in about 1% of the patients per year and to bipolar II disorders in about 0.5% per year. Risk factors for a change from depression to BP-I disorder were male sex and an early onset of the disorder; risk factors for a change from depression to BP-II disorder were female sex, a later onset of the disorder and a positive family history of mania.
Across the entire lifetime, every new episode of depression brings a new risk for mania; more than half of our severe mood disorder cases became bipolars. The risk of depression developing into bipolar disorder remains constant lifelong.
The diagnostic classification of ICD-9 met RDC criteria for bipolar disorder in only 90% of cases. Part of the data collected in retrospect may be less reliable; the prospective data were only collected every 5 years from 1965 to 1985 using multiple sources; mild manifestations between the follow-ups may have been partially missed. The sample of subsequent hospital admissions for major depression and mania represents a severe group of patients and generalisations to ambulatory cases may not be possible. Not all risk factors for diagnostic conversion described in the literature could be assessed in this study.
- SourceAvailable from: scalesandmeasures.netArchives of General Psychiatry 02/1972; 26(1):57-63. · 13.77 Impact Factor
- Psychopharmacology bulletin 02/1987; 23(1):68-73. · 1.35 Impact Factor
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ABSTRACT: It is generally accepted that one of the most important predictors of recurrence in depressive and bipolar disorders is the number of previous episodes. However, very few studies have considered the individual tendency toward recurrence in analyses of the effect of the number of episodes on the risk of subsequent recurrence in affective disorder. Frailty models were used to estimate the effect of the number of episodes on the rate of recurrence taking into account the individual frailty toward recurrence. The study base consisted of 406 patients, 186 patients with depressive disorder and 220 patients with bipolar disorder, who were admitted between 1959 and 1963 to the Psychiatric Hospital University of Zurich with an affective episode and followed up to 1997. The individual rate of subsequent recurrence was found to increase with the number of episodes even when the effect was adjusted for the individual frailty toward recurrence. The effect of episodes was the same in depressive and bipolar disorders and for men and women. It seems increasingly valid that in depressive and bipolar disorders, the risk of subsequent recurrence increases with the number of episodes.Acta Psychiatrica Scandinavica 06/2004; 109(5):339-44. · 4.86 Impact Factor