Background. While neuropsychological studies have consistently
reported impaired cognition in
elderly patients with unipolar depression, studies of cognitive function
in
younger patients with
depression have produced equivocal results. The aim of this study was to
examine the presence and
nature of cognitive deficits in young patients with depression.
Methods. Neuropsychological function was assessed in 20 young
patients
with unipolar depression,
in comparison to 20 age-, education- and IQ- matched controls. Subtests
from
the Cambridge
Neuropsychological Test Automated Battery (CANTAB) were employed, as this
battery has proved
sensitive to deficits in middle-aged and elderly patients with depression.
Results. The patients were not impaired for short-term memory
capacity,
spatial working memory,
planning ability, cognitive speed, delayed matching to sample or recognition
memory. Compared
to controls, the patients showed impaired subsequent movement latencies
on
the Tower of London
task, suggesting deficits in the ability to sustain motor responses in
depression. The depression
group were also impaired on the task of attentional set shifting, requiring
more trials to criterion
at the intradimensional stage of the task and being more likely to fail
the
task at the
extradimensional shift stage than controls. Further analysis indicated
that
half of the depression
group failed to complete all stages of the set shifting task. These patients
were more likely to have
required in-patient hospitalization at some time during their illness.
Conclusions. These results indicate that there are specific
cognitive
deficits in young patients with
depression and that their presence may be related to a history of hospitalization.