Diagnosing Unipolar Depression (AQA GCSE Psychology)

Revision Note

Claire Neeson

Written by: Claire Neeson

Reviewed by: Lucy Vinson

Use of the International Classification of Diseases (ICD) to diagnose unipolar depression

  • The ICD stands for the International Classification of Diseases which is now in its eleventh edition, having last been published in 2022 

  • It is a diagnostic tool used by any medical professional who is qualified to give a diagnosis of both physical and  mental disorders e.g. doctors, clinicians, psychiatrists

  • Physical illnesses, such as COVID-19, can also be a focus of the ICD 

  • The ICD works on a global scale, using data it has gathered to inform worldwide health initiatives and research into disease (both physical and mental)

  • It can be used to diagnose depression via its classification of the symptoms that determine either mild, moderate or severe depression

Number & severity of symptoms of unipolar depression

  • The ICD states that there are three key symptoms of unipolar depression:

    • Low mood (dysphoria): overwhelming sadness, possible anger, feelings of hopelessness and despair

    • Loss of interest in activities or hobbies that once brought joy

    • Reduced energy levels; this could lead to someone being unable/unwilling to go to work, to socialise, even to be able to get out of bed

  • A diagnosis of mild depression would need the person to show two of the three key symptoms above plus another two symptoms (see the previous page on the different types of depression)

  • For someone to be diagnosed with moderate depression they would need to show four or more symptoms in total

  • Diagnosing severe depression would need a person to show seven or more symptoms in total

  • The symptoms (for mild, moderate and severe depression) should have been present continually for more than two weeks

Worked Example

Here is an example of a question you might be asked on this topic - for AO3.

AO3: You need to analyse and evaluate key concepts, ideas, theories and research.

Question: A questionnaire may be used to determine whether someone has unipolar depression. Briefly evaluate the use of questionnaires in researching depression.  [3]

Model answer:

  • A strength of using questionnaires to research depression is that they use standardised questions which can be used with large samples in order to establish how widespread depression is within a population.

  • Using a large sample and quantitative data from questionnaires increases reliability.

  • A weakness of using questionnaires to research depression is that depression is a socially sensitive topic so people may lie or be prone to social desirability bias in their answers which would decrease the validity of the findings.

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Claire Neeson

Author: Claire Neeson

Expertise: Psychology Content Creator

Claire has been teaching for 34 years, in the UK and overseas. She has taught GCSE, A-level and IB Psychology which has been a lot of fun and extremely exhausting! Claire is now a freelance Psychology teacher and content creator, producing textbooks, revision notes and (hopefully) exciting and interactive teaching materials for use in the classroom and for exam prep. Her passion (apart from Psychology of course) is roller skating and when she is not working (or watching 'Coronation Street') she can be found busting some impressive moves on her local roller rink.

Lucy Vinson

Author: Lucy Vinson

Expertise: Psychology Subject Lead

Lucy has been a part of Save My Exams since 2024 and is responsible for all things Psychology & Social Science in her role as Subject Lead. Prior to this, Lucy taught for 5 years, including Computing (KS3), Geography (KS3 & GCSE) and Psychology A Level as a Subject Lead for 4 years. She loves teaching research methods and psychopathology. Outside of the classroom, she has provided pastoral support for hundreds of boarding students over a four year period as a boarding house tutor.