Psychotic and mixed episodes linked in bipolar disorder

Nov 8 2012

By Mark Cowen, Senior medwireNews Reporter

Results from a large Danish study show that psychotic depression (PD), psychotic mania (PM), and mixed affective episodes (MAE) share significant associations in patients with bipolar disorder.

Søren Dinesen Østergaard (Aarhus University Hospital) and colleagues found that bipolar disorder patients with psychotic symptoms during episodes of mania or depression were at increased risk for MAE, and vice versa. And patients with PD were at increased risk for PM, and vice versa.

"We believe that the associations detected in our analysis have important clinical implications," the researchers comment.

"The apparent link between both PM and MAE and PD and MAE suggests that clinicians should be attentive of mixed symptomatology if a patient has experienced psychotic affective episodes, and vice versa. Similarly, the association between PM and PD encourages a focus on psychotic symptoms in manic or depressive episodes if the patient has suffered from psychotic symptoms during episodes involving the opposite mood pole."

The findings come from a study of 14,529 bipolar disorder patients from the Danish Psychiatric Central Research Register who were diagnosed with the condition between 1994 and 2010.

Overall, 19%, 15%, and 17% of participants had experienced PM, PD, and MAE, respectively.

After accounting for gender and age at diagnosis, logistic regression analysis revealed that PM and MAE were significantly associated, at an adjusted odds ratio (aOR) of 1.26; PD and MAE were significantly associated, at an aOR of 1.24; and PM and PD were significantly associated, at an aOR of 1.28.

When only patients with a history of severe depression were considered - in order to test for a potential severity bias in the results involving PD - the team found that the associations remained significant for both PD and MAE (aOR=1.17), and PM and PD (aOR=1.37).

The researchers note that PD preceded PM in 56% of the 383 patients who experienced both types of episodes, PM preceded MAE in 67% of 537 patients, and PD preceded MAE in 62% of 420 patients.

They also found that patients with PM, PD or MAE experienced more affective episodes, had more hospital admissions, and were hospitalized for longer periods than other bipolar patients.

Østergaard et al conclude: "According to this register-based study of 14,529 patients with ICD-10 bipolar disorder, PM, PD, and MAE are all associated with one another.

"This knowledge should be taken into consideration by clinicians when monitoring patients with bipolar disorder and by nosologists when defining the criteria and potential subtypes for mixed affective episodes for the upcoming DSM-5 and ICD [International Classification of Diseases]-11."

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