Background: This paper explores whether individuals with a mood disorder can identify the nature and duration of depressive and manic prodromes.
Methods: Seventy-three publications of prodromal symptoms in bipolar and unipolar disorders were identified by computer searches of seven databases (including MEDLINE and PsycLIT) supplemented by hand searches of journals. Seventeen studies (total sample=1191 subjects) met criteria for inclusion in a systematic review.
Results: At least 80% of individuals with a mood disorder can identify one or more prodromal symptoms. There are limited data about unipolar disorders. In bipolar disorders, early symptoms of mania are identified more frequently than early symptoms of depression. The most robust early symptom of mania is sleep disturbance (median prevalence 77%). Early symptoms of depression are inconsistent. The mean length of manic prodromes (>20 days) was consistently reported to be longer than depressive prodromes (<19 days). However, depressive prodromes showed greater inter-individual variation (ranging from 2 to 365 days) in duration than manic prodromes (1-120 days).
Limitations: Few prospective studies of bipolar, and particularly unipolar disorders have been reported.
Conclusions: Early symptoms of relapse in affective disorders can be identified. Explanations of the apparent differences in the recognition and length of prodromes between mania and bipolar depression are explored. Further research on duration, sequence of symptom appearance and characteristics of prodromes is warranted to clarify the clinical usefulness of early symptom monitoring.