Anxiety exacerbates bipolar disorder

Comorbid anxiety disorders appear to be common among people with bipolar disorder, contributing to greater illness severity and impairment, as well as suicide attempts, say researchers.

"It is important to determine whether effective treatment of anxiety symptoms can lessen bipolar disorder severity, improve response to treatment of manic or depressive symptoms, or reduce suicidality," they comment in the American Journal of Psychiatry.

For their study, Naomi Simon (Massachusetts General Hospital, Boston, USA) and colleagues examined the lifetime and current rates of anxiety in 500 patients with bipolar I or II disorder, who were participating in the Systematic Treatment Enhancement Program for Bipolar Disorder.

They found that lifetime comorbid anxiety disorders were common in the bipolar patients, with a lifetime prevalence of 51.2% and 30.5% for any current anxiety disorder. Greater overall anxiety comorbidity was seen among patients with bipolar I disorder relative to bipolar II disorder.

Patients with anxiety disorders, compared with those without, developed bipolar disorder at a younger age, had a decreased likelihood of recovery, poorer role functioning and quality of life, and spent less time euthymic.

Comorbid anxiety disorders were also associated with a greater risk of suicide, and individuals with anxiety were 2.45 times more likely to have attempted suicide than those without the condition.

The researchers note that, although patients with anxiety were also significantly more likely than their non-anxious counterparts to have substance abuse disorders, the effect of anxiety on functioning was independent of these substance abuse disorders

"Early anxiety may represent a prodromal symptom of bipolar disorder, or alternately, anxiety and bipolar disorders may share an associated biology or risk," comment Simon et al.

They note that further research examining the impact of anxiety on treatment response and course in bipolar disorder is currently ongoing.

"These efforts may further elucidate the... need for additional or alternative intervention for patients with bipolar disorder and anxiety comorbidity," the team adds.

Am J Psychiatry 2004; 161: 2222-2229