Extent and kind of cognitieve dysfunctions in patients suffering from bipolar disorder: their determinants and impact on clinical and functional outcome

Cognitive dysfunctions have increasingly become a focus of research in bipolar
disorders. It is estimated that one-third of patients with bipolar disorder
suffer from cognitive dysfunctions, even in a clinically asymptomatic phase.
However, due to relatively few studies and many methodological pitfalls, the
exact extent and kind of cognitive dysfunctions in bipolar disorders, as well
as information about the suspected clinical and biological determinants remains
unclear. Also, the relationship between cognitive dysfunctions and clinical and
functional outcome parameters are understudied. More knowledge could lead to an
addendum of the standard assessment in patients with bipolar disorder (like
schizophrenic patients), and may possible result in new therapeutic approaches
to improve quality of care, better treatment adherence and ultimately better
functional outcome.

The primary objective is the extent and kind of cognitive deficits in patients
suffering from bipolar disorders compared to healthy controls and patients with
a lifetime diagnosis of unipolar depressive disorder. Secondary objectives
specify the clinical possible determinants of cognitive dysfunctions (for
example illness and patient characteristics and HPA axis functioning) and the
(possible) consequences of cognitive dysfunctions (psychosocial functioning and
illness outcome).

Cross sectional design

This study is an enlargment of a previous approved study (METC 2005/236). This
project only requires one extra visit to the UMC Groningen. The total study
will be performed by patients in around 5 hours and by healthy controls in 3
hours, including the cognitive tests, evaluation of patient- and illness
characteristics and outcome measurements (partly by interview, partly by
questionnaires), venapuncture and saliva samples performance to perform
cortisol measurements. The participation in venapuncture of 1 tube of 10 cc. to
collect a reserve sample has minimum risks. Saliva sampling itself takes place
at home and only requires a minimum of time (maximum of 20 minutes) in 2
consecutive days. During saliva sampling patients are asked to ingest 0.5 mg
dexamethason, which is not a harmful drug that inhibits the release of cortisol
for a maximum of 24 hours and rarely causes the next morning a higher level of
alertness, comparable with the intake of one cup of coffee.