Cognitive Impairment in Psychiatric Illness

Bipolar disorder

Though originally bipolar disorder was considered to spare cognition, cognitive impairment relative to healthy controls has been increasingly recognized. This is to a lesser degree when compared to schizophrenia, and social cognition is generally spared (Bora 2016).

Schizophrenia

Schizophrenia was originally called dementia praecox by Kraepelin due to its recognized cognitive deficits across multiple domains (verbal and visual memory, working memory, social cognition, processing speed, attention, executive function) and is a major source of functional impairment. Compared to bipolar disorder, these deficits generally present earlier and deficits in social cognition (including emotion recognition, theory of mind) are more specific to schizophrenia (Bora 2016).

Depression

Inattention / poor concentration is a core diagnostic criteria for generalized anxiety disorder and major depressive disorder (DSM-V)

• i.e. 90% of patients with depression in mental health clinics report difficulty with concentration which often persist after remission of depressive episode

References

American Psychiatric Association. Diagnostic and statistical manual of mental disorders: DSM-5 (American Psychiatric Association).

Bora, E. Differences in cognitive impairment between schizophrenia and bipolar disorder: Considering the role of heterogeneity. Psychiatry Clin. Neurosci. 10 (2016). https://pubmed.ncbi.nlm.nih.gov/27233969/

Gaynes, B. N. et al. A direct comparison of presenting characteristics of depressed outpatients from primary vs. specialty care settings: preliminary findings from the STAR*D clinical trial. Gen. Hosp. Psychiatry 27, 87–96 (2005). https://pubmed.ncbi.nlm.nih.gov/15763119/