Unrecognised bipolar disorder among UK primary care patients prescribed antidepressants: an observational study

Background

Bipolar disorder is not uncommon, is associated with high disability and risk of suicide, often presents with depression, and can go unrecognised.

Aim

To determine the prevalence of unrecognised bipolar disorder among those prescribed antidepressants for depressive or anxiety disorder in UK primary care; whether those with unrecognised bipolar disorder have more severe depression than those who do not; and the accuracy of a screening questionnaire for bipolar disorder, the Mood Disorder Questionnaire (MDQ), in this setting.

Design and setting

Observational primary care study of patients on the lists of 21 general practices in West Yorkshire aged 16–40 years and prescribed antidepressant medication.

Method

Participants were recruited using primary care databases, interviewed using a diagnostic interview, and completed the screening questionnaire and rating scales of symptoms and quality of life.

Results

The prevalence of unrecognised bipolar disorder was 7.3%. Adjusting for differences between the sample and a national database gives a prevalence of 10.0%. Those with unrecognised bipolar disorder were younger and had greater lifetime depression. The predictive value of the MDQ was poor.

Conclusion

Among people aged 16–40 years prescribed antidepressants in primary care for depression or anxiety, there is a substantial proportion with unrecognised bipolar disorder. When seeing patients with depression or anxiety disorder, particularly when they are young or not doing well, clinicians should review the life history for evidence of unrecognised bipolar disorder. Some clinicians might find the MDQ to be a useful supplement to non-standardised questioning.