The impact of general intellectual ability and white matter volume on the functional outcome of patients with Bipolar Disorder and their relatives.
BACKGROUND
There is substantial evidence that cognitive deficits and brain structural abnormalities are present in patients with Bipolar Disorder (BD) and in their first-degree relatives. Previous studies have demonstrated associations between cognition and functional outcome in BD patients but have not examined the role of brain morphological changes. Similarly, the functional impact of either cognition or brain morphology in relatives remains unknown. Therefore we focused on delineating the relationship between psychosocial functioning, cognition and brain structure, in relation to disease expression and genetic risk for BD.


METHODS
Clinical, cognitive and brain structural measures were obtained from 41 euthymic BD patients and 50 of their unaffected first-degree relatives. Psychosocial function was evaluated using the General Assessment of Functioning (GAF) scale. We examined the relationship between level of functioning and general intellectual ability (IQ), memory, attention, executive functioning, symptomatology, illness course and total gray matter, white matter and cerebrospinal fluid volumes.


CONCLUSIONS
Cross-sectional design.


RESULTS
Multiple regression analyses revealed that IQ, total white matter volume and a predominantly depressive illness course were independently associated with functional outcome in BD patients, but not in their relatives, and accounted for a substantial proportion (53%) of the variance in patients' GAF scores. There were no significant domain-specific associations between cognition and outcome after consideration of IQ.


CONCLUSIONS
Our results emphasise the role of IQ and white matter integrity in relation to outcome in BD and carry significant implications for treatment interventions.
Institute of Psychiatry, King's College London, King's Health Partners, London, UK.
Irene
I
Forcada
Efstathios
E
Papachristou
Maria
M
Mur
Tessa
T
Christodoulou
Jigar
J
Jogia
Abraham
A
Reichenberg
Eduard
E
Vieta
Sophia
S
Frangou
D000293:Adolescent; D000328:Adult; D000368:Aged; D001288:Attention; D001714:Bipolar Disorder / Q000175:diagnosis* / Q000235:genetics / Q000473:pathology* / Q000523:psychology*; D001921:Brain / Q000473:pathology*; D003430:Cross-Sectional Studies; D056344:Executive Function; D005190:Family / Q000523:psychology*; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D007360:Intelligence; D007361:Intelligence Tests; D008279:Magnetic Resonance Imaging; D008297:Male; D008568:Memory; D008875:Middle Aged; D009483:Neuropsychological Tests; D009929:Organ Size; D055815:Young Adult