K. Uwajeh1, K.I Egbuchulem2, O.A Afolabi3

  1. Department of Clinical Psychology, University of California, Southern California, United States of America.
  2. Division of Paediatric Surgery, Department of Surgery, University College Hospital, Ibadan, Oyo State.
  3. Department of Psychiatry, University College Hospital, Ibadan, Oyo State.


Dr. K. Uwajeh
Department of Clinical Psychology,
University of California,
United States of America
Submission Date: 4th Dec., 2023
Date of Acceptance: 1st April, 2024
Publication Date: 30th April, 2024


Depression is a pandemic that has plagued the world since time immemorial, and it has many implications. According to the World Health Organization (WHO), depression is a leading cause of disability and affects 5% of the world’s population. The prevalence of depression has reportedly been on the rise since COVID-19 possibly due to the stress, loneliness, and reduced ability to work occasioned by the pandemic.1 Depression is not only a major contributor to the global burden of disease but also a major cause of suicide, which claims nearly one million lives annually and is the fourth leading cause of death in individuals aged 15 – 29 years.2, 3

Major Depressive Disorder (MDD) is the diagnostic term used to depict clinical depression in the Diagnostic and Statistical Manual of Disease 5th edition (DSM-V). A diagnosis of MDD requires at least five symptoms, which must include at least one of the core symptoms of depressed or irritable mood (negative affect) and loss or reduced interest in previously pleasurable activities. The other symptoms include loss of energy or fatigue, significant weight change, change in appetite, change in sleep resulting in hypersomnia or insomnia, psychomotor retardation or agitation, feelings of worthlessness or excessive or inappropriate guilt, diminished ability to think or concentrate, or indecisiveness, recurrent thoughts of death. These should have occurred persistently for at least two weeks and causes significant distress or impairment in functioning. The symptoms are also not due to physiological, or substance use or another medical condition.4 Furthermore, in addition to the emotional and motivational features, MDD can have cognitive symptoms including impaired attention and concentration, memory disturbances and cognitive distortions.

Considering the above, therefore we can say that some of the clinical features of MDD bear some semblance to the impact of depression on cognition, emotion, and motivation.5 – 7This essay therefore aims to connect the observable symptoms of Major Depressive Disorder (MDD) to the impact of depression on cognition, emotion, and motivation.