A Comparative Study of Cognitive Impairment between Patients with Unipolar and Bipolar Depression

Introduction: Mood disorders fall into the basic groups of elevated mood, such as mania or hypomania; depressed mood, of which the best-known is major depressive disorder commonly called unipolar depression and moods which cycle between mania and depression, known as bipolar disorder. Cognitive impairment in unipolar and bipolar depression has been the focus of intensive investigation during the past decade. Aim:1) To access cognitive impairment in patients with unipolar depression and bipolar depression 2) To find out the difference in cognitive impairments between patients with unipolar and bipolar depression 3) To find out the correlation between severity of depression and cognitive impairment between patients of unipolar and bipolar depression. Methodology: Sample comprises of 100 patients of which 58 patients were of unipolar depression and 42 patients of bipolar depression. Patients were taken according to DSM-IV TR Criteria and those who were fulfilling our inclusion criteria. Tools: Tools used were Hamilton Depression Rating Scale and PGI Memory Scale and Cognitive Symptoms Checklist. Result and Discussion: Impairment in memory and cognitive symptoms was found in patients of unipolar and bipolar depression as compared to control group and results indicates that with the increase in depression memory decreases and cognitive impairment increases. The above shows the correlation between HAMD and cognitive symptoms of unipolar depressive patients on CSC. There was positive correlation ( 0.415, 0.480, 0.259, 0.443, 0.360) between depression and cognitive symptoms including attention/concentration, executive functioning, memory, visual processing and language. and bipolar group found to be more impaired than unipolar depressive patients on CSC including attention/concentration, executive functioning, memory, visual processing and language. These results were in consonance with other studies. Several studies have shown that MDD patients to show deficits on attention related tasks (Cohen et al., 2001; Landro et al, 2001; Kostsier et al, 2002; Liu et al, 2002; Ravnkilde et al., 2002; Hammer et al, 2008; Simons et al, 2009). There are reports of findings in different cognitive domains, attention, memory and psychomotor speed (Austinct et al; 2001, Castareda et al; 2008). Several other recent studies showed an association between memory impairment and Major Depressive Disorder (Egeland et al, 2003b., Porter et al., 2003; Airaksinen et al, 2004; Campbell and MacQueen, 2004; Vythilingam et al., 2004; Mathews et al., 2008). In acute phase of illness, the impairment in EF has been frequently reported (Harvey et al; 200). The findings are shown in different cognitive domains, such as executive functions, attention, memory and psychomotor speed (Asa Hammar and GuroArdal 2009). There is cognitive dysfunction in patients with bipolar or unipolar disorder. Further results of this study shows the correlation between HAMD scores and memory of unipolar depression group. Results showed that increase in depression scores leads to decrease in memory. This study also compares the correlation between HAMD scores and memory of bipolar depression patients and results indicates that increase in depression leads to decrease in memory. These results were supported by the studies conducted in the recent literature regarding depressive cognition it was also find consistently implicated working memory, attention and executive dysfunction and processing speed (Doumas et al. 2012, Elderkin Thomson et al. 2010, Rosenberg et al. 2010, Marazziti et al. 2010, Nakano et al. 2008, Weiland-Fiedler et al. 2004).