Gender differences in immediate memory in bipolar disorder

Background. Gender is known to modulate the clinical course and severity of bipolar disorder (BD). Although cognitive abnormalities are an established feature of BD, there is limited information regarding whether gender also influences the pattern and severity of cognitive impairment. Method. We evaluated the performance of 86 remitted patients with BD, type 1, (BD-I) (36 male and 50 female) and 46 healthy participants (21 male and 25 female) on tasks of general intellectual ability, memory encoding, recognition and retrieval, response inhibition and executive function (abstraction and perseveration). The impact of illness severity in patients was assessed using the global assessment of functioning (GAF). Results. We found a gender effect and an interaction between diagnosis and gender on immediate memory, implicating encoding and retrieval processes, both showing male BD-I patients being disadvantaged compared with female patients and healthy controls. Immediate memory correlated with GAF scores and this association was statistically significant for male BD-I patients. Conclusions. Our findings suggest that gender differences in BD-I are associated with memory function, particularly processes relating to encoding and retrieval, and may contribute to poor functional outcome particularly in men.