Cognitive impairment in depression could present as subjective and objective, but the intensity of subjective impairment is higher and is not correlated with the deficits measured by neuropsychological tests. Subjective cognitive impairment lowers quality of life and is associated with the severity of depression. Among depressive patients, negative emotional bias is present. It is better memory for negative or positive information than for neutral information. We hypothesized that rumination is associated with subjective cognitive impairment.

The study was performed through the online PsyToolkit platform. The study sample consisted of 168 healthy controls and 93 patients with depression were enrolled in the study. Participants completed questionnaires and performed a memory task that contained emotional words. The forty words were chosen from the Nencki Affective Word List. The list for memory test consists of 5 words from each Category: Happiness, Anger, Fear, Sad, Disgusting, and Neutral, and 10 words from category ‘Unclassified’ to balance the valence and arousal of the set. After 15 minutes, they recognized old words from the list of 80 words. Half of them were the same as in the first part, and other words were new, chosen with the same criteria. Depression symptoms were measured using the Beck Depression Inventory-II, subjective cognitive impairment with the Perceived Deficits Questionnaire-20, and intensity of rumination with the Polish Questionnaire of Rumination.

Subjective cognitive impairment and rumination were higher in patients with depression. They also had a higher error rate than healthy controls U = 6462.5; p = .021, especially in words from the neutral (U = 6292; p = .008) and happiness category (U = 6585; p = .031). However, there was no association between subjective cognitive impairment and performance in memory tasks. The regression analysis showed that depressive symptoms and intensity of rumination are better predictors of subjective cognitive deficits than objective performance on a memory task. The results of PDQ-20 were correlated with the error rate of words from categories: Happiness (r = -.162**), Sad (r = -.116*) and Neutral (r = -.145**). Words from categories Happiness, Disgust and Neutral were significantly better recognized than Unclassified, Fear or Sad group of words χ 2 F (6) = 132.685; p < .001. In MDD group recognition of Disgust words were statistically highest than Anger and Fear words χ 2 F (6) = 36.795; p < .001. The recognition of Happiness and Neutral word were not significantly different to other words.

Cognitive problems are common in depression and affect quality of life. Subjective cognitive impairment is more closely related to rumination than objective cognitive impairment among healthy participants and patients with major depressive disorder. Emotional bias among depressive patients has been partially confirmed. Emotional impact is important for memory of words and subjective perception of cognition.