Depression 03 Mar, 2017 Read Time: 1 min

A constellation of symptoms

Depression – a constellation of symptoms

Depression is a common mental disorder affecting a large number of patients globally, and having a wider impact on their friends, families, carers and employers.1 It is a clinically heterogeneous condition, with a generally underestimated variety of symptoms spanning emotional, physical and cognitive domains.2,3 Despite becoming increasingly recognised as a significant component of depression in many patients, cognitive symptoms are often poorly understood in clinical practice.2,3

While a patient must present with either depressed mood or anhedonia to be diagnosed with depression, they may also be experiencing any number of the following symptoms to a greater or lesser extent:2

The Diagnostic and Statistical Manual of Mental Disorders covers only a limited range of cognitive symptoms that can be present in patients with depression. Additional cognitive deficits have been reported in depression, including:4–6

  • Difficulty in maintaining attention
  • Poor organisation/planning
  • Decline in mental sharpness
  • Difficulty learning new concepts
  • Reduced thinking speed
  • Poor judgement
  • Difficulty recalling words

Cognition in depression – the facts
Cognitive symptoms can have a devastating impact on patients’ day-to-day lives, and are implicated as a principal mediator of psychosocial impairment and functional disability, particularly with performance at work.7,8

Cognitive deficits in depression are a principal mediator of functional disability, notably impaired workplace performance.5,8

Cognitive symptoms can often persist beyond the cessation of emotional manifestations like sadness, anxiety and anhedonia:2

  • A review of studies in major depressive disorder found that pronounced deficits in executive function are seen in around 20–30% of patients7
  • In a meta-analysis of 644 patients experiencing their first episode of major depression, cognitive performance was significantly impaired across domains including psychomotor speed, attention, visual learning and memory, and executive function9
  • In a Dutch study of 267 patients with depression, cognitive symptoms were present 94% of the time during major depressive episodes10
  • In the same Dutch study, cognitive symptoms were shown to persist for an average of 44% of the time during periods of remission10

There is also a direct link between cognitive symptoms and risk of relapse, with one study showing that more than 75% of patients with residual cognitive symptoms relapsed within 10 months of achieving remission.11 This highlights the importance of recognising and monitoring the full constellation of emotional, physical and cognitive symptoms in your patients with depression.

References

  1. Depression Factsheet. WHO. Available at: http://www.who.int/mediacentre/factsheets/fs369/en/. Accessed July 2015.
  2. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Health Disorders. 5th Washington, DC: American Psychiatric Association; 2013.
  3. Jarema M et al. Psychiatr Pol 2014; 48(6): 1105–1116.
  4. Marazziti D et al. Eur J Pharmacol 2010; 626(1): 83–86.
  5. Hammar A, Ardal G. Front Human Neurosci 2009; 3: 26.
  6. Fehnel SE et al. CNS Spectr 2013; 25: 1–10.
  7. McIntyre RS et al. Depress Anxiety 2013; 30(6): 515–527.
  8. Lam RW et al. Can J Psychiatry 2014; 59(12): 649–654.
  9. Lee RSC et al. J Affect Disord 2012; 140: 113–124.
  10. Conradi HJ et al. Psychol Med 2011; 41(6): 1165–1174.
  11. Paykel ES et al. Dialogues Clin Neurosci 2008; 10: 431–437.