A distinct pattern of memory and attention deficiency in patients with depression

Depression related cognitive deficits are frequently considered as simple epiphenomena of the disorder. However, whether or not the depression might directly bring about cognitive deficits is still under investigation. This study was to investigate the distinct pattern of cognitive deficits in patients with depression by comparing the cognitive function before and after anti-depressive drug therapy.

Sixty cases of patients, first-time diagnosed with depression, were assessed by 17-item Hamilton Rating Scale for Depression (HAMD17scale). The memory ability was tested by quantitatively clinical memory scale, while the attention ability by modified Ruff 2&7 Selective Attention Test. Forty-two healthy volunteers were recruited as controls. The depressive patients were treated with Venlafaxine (75 - 300 mg/d), Fluoxetine (20 - 40 mg/d), Paroxetine (20 - 40 mg/d), and Sertraline (50 - 150 mg/d). After 12 weeks treatment, patients were tested again by HAMD17scale, quantitatively clinical memory scale, and modified Ruff 2&7 selective attention test to assess the effect of anti-depressive drugs on cognitive deficits.

The memory quotient (MQ) was significantly lowered in depressive patients. The selection speed was also significantly decreased and the number of missing and error hits increased in the depression group as compared to control. However, there was no significant difference in clinical memory scale and Ruff 2&7 selective attention test between mild-to-moderate and severe depression group. Importantly, after anti-depressive drug therapy, the HAMD17 scale scores in depressive patients were significantly decreased, but the MQ, directional memory (DM), free recall (FR), associative learning (AL), and face recognition were comparable with those before the treatment. Furthermore, the selection speed and the number of missing and error hits were also not significantly different after anti-depressive drugs treatment.

Depressive patients suffer from short-term memory deficits, and attention extent, stability and rearrangement deficiency. Even though anti-depressive drugs sufficiently relieve the cardinal presentation of depression, they could not successfully alleviate the accompanying cognitive deficits. This might indicate a distinct pattern of cognitive deficits in patients with depression.