Relationship between anosognosia and depression in aphasic patients

Depression and reduced awareness of illness (anosognosia) can be frequent complications following a brain lesion
but the relationship between these two syndromes is still unclear. While some researchers suggested a protective
function of anosognosia from depression, others deny a functional relationship. We investigated anosognosia
and depression in a group of 30 left-brain-damaged patients using specialized methodology for aphasic patients.
We observed that anosognosic patients showed levels of depression comparable to those of aware patients and
that anosognosia was highly selective for specific deficits. Our findings suggest that reduced awareness for a deficit
does not play a crucial role in mood disorder, whereas “simply” suffering for a deficit can per se increase the likelihood
of depression. Moreover, whereas depressed and nondepressed patients did show a similar impairment
on the nonverbal executive function test, almost all patients showed anosognosia associated with impairment
on executive functions. Finally, depressed patients tend to deny or minimize their own mood disorder, confirming
that anosognosia can also concern mood status and that self-rating measures for depression could be quite
controversial.