In half of patients who are diagnosed with bipolar disorder, onset episode is one of depression. The proportion is 2/3 in bipolar 2 disorder.Many may have multiple depressive episodes before manic or mixed episode appears facilitating a diagnosis of bipolar disorder. Predicting who will go on to develop bipolar , if possible, would be huge benefit.
Several factors have been identified previously as associated with a later diagnosis of bipolar disorder in some one presenting with depression. This include 1.family history of bipolar disorder, (2) cyclothymic or hyperthymic temperament, (3) illness-onset before age 25 years, (4) multiple shorter depressive episodes, (5) stressful precipitants at onset,( 6) presence of ADHD and (7) pathological mood-elevation during treatment with an antidepressant or other mood-elevating agent (stimulant, corticosteroid). Symptoms like prominent agitation, anxiety, psychotic features and atypical symptoms (hypersomnia, hyperphagia, psychomotor retardation) are also suggested as predictors in some studies.
Leonardo Todo and team from International Consortium for Bipolar Disorder Research ( USA & Italy) report the clinical characteristics that predict later bipolar diagnosis. Of the 2146 patients in an episode of depression , 30% met criteria for bipolar disorder later. Average time of observation was around 13 years.
Seven factors were found to be significantly predictive of bipolar disorder.
1. 4 or more depressive episodes before intake 2. suicidal acts (gestures or acts) 3. cyclothymic temperament 4. First degree family history of bipolar disorder 5. substance abuse 6. younger age of onset 7. male sex. First 4 factors were more strongly associated with later bipolar diagnosis.
if your patient has two factors, prediction has a sensitivity (71 %) and specificity (62%). i.e. 69% of diagnostic assumption of bipolar will be correct.
Limitations: all patients did not provide all information about predictive factors, recall of past events may be biased.
Questions like “are unipolar and bipolar two different disorders or two expressions of one disorder?” are still hotly debated. Is it that the potential for bipolarity is there at the start of expression of illness or is it a spontaneous change that occurs in the course of illness ( ? due to environmental factors or treatment factors)? The present study does not address these issues, but are relevant for future discussion.
Conclusions: Certain clinical factors can predict the possibility of a patient presenting with depression as eventually diagnosed as bipolar disorder. It is important that clinicians make such assessments to ensure optimum treatments.
Summary of the article:
Tondo L, Visioli C, Preti A, Baldessarini RJ.
J Affect Disord. 2014 Oct;167:44-9