Transdiagnostic emotion regulation processes in bipolar disorder and insomnia.

Research and treatment have traditionally adopted a 'disorder-focused' approach by targeting one specific disorder, aiming to understanding its cause, maintenance and treatment. The aim of the present study was to contribute to the burgeoning interest in examining common, or 'transdiagnostic,' processes across disorders. Three candidate transdiagnostic processes involved in emotion regulation - rumination, worry, and automatic negative thoughts - were examined in euthymic bipolar I disorder (n=21) and insomnia (n=19), and a non-clinical control group (n=20). Rumination and worry were endorsed to a larger degree by the bipolar and insomnia groups compared to the control group. However, while the bipolar group had more negative automatic thoughts than the control group, there were no significant differences in negative automatic thoughts between the bipolar and insomnia groups or the insomnia and control groups. These results suggested that rumination and worry, but not negative automatic thoughts, might be common across bipolar disorder and insomnia. However, these findings no longer remained significant when current symptoms of anxiety and depression were controlled for. Prospective and experimental studies are needed to test the extent to which these processes contribute to the etiology or maintenance of insomnia and bipolar disorder.