Diagnostic criteria

• Affect (noun)


  Another word for emotion
• Affective disorders


  Conditions that affect (verb) our emotions
• Emotions


  Relatively temporary and change according to the situation
• Moods


  More stable, meaning they last longer and do not change as quickly as emotions
• Mood disorders


  • People often experience extended periods of time where either negative and/or positive emotions dominate and affect their thoughts and feelings in ways that can lead to dysfunction, distress and even danger
• Episode


  A time period in which a certain mood dominates
• Types of mood episodes

  • Depressive
  • Manic
  • Hypomanic
  • Mixed
• Polar


  The idea that our moods are on a continuum (or scale), with very high mood at one end and very low mood at the other
• We all experience changes in mood each day, but generally these average out within the normal range</b>
• Mood disorders


  • Characterised by the duration and intensity of the moods experienced
• Unipolar depressive episodes


  Moods within normal range but sometimes mood drops to very low end of scale
• Depressive episode (ICD-11 definition)

  A period of depressed mood or diminished interest in activities occurring most of the day, nearly every day during a period lasting at least two weeks accompanied by symptoms such as difficulty concentrating, feelings of worthlessness or excessive inappropriate guilt, hopelessness, recurrent thoughts of death or suicide, changes in appetite or sleep, psychomotor agitation or retardation, and reduced energy or fatigue
• A person who has experienced at least two depressive episodes will be diagnosed with recurrent depressive disorder
• Specifier for depressive episode

  Mild, moderate or severe to describe the intensity of the episode based on the range of symptoms experienced and their impact on the person's day-to-day functioning
• The doctor will also note whether the depressive episode occurred with or without psychotic symptoms
• Bipolar disorder (type 1)


  Experiences very low moods (unipolar depression symptoms) as well as periods of very high mood (manic episodes)
• Manic episode (ICD-11 definition)

  Extreme mood state lasting at least one week unless shortened by a treatment intervention, including symptoms such as euphoria, irritability and expansiveness, inflated sense of self-importance, highly active, decreased need for sleep, easily distracted, impulsive and reckless
• Bipolar disorder


  Person may alternate between depressive and manic episodes that last a week or more, or experience mixed episodes where aspects of both mania and depression are apparent within the same day or week
• Bipolar disorder (type 2)


  Experiences the same intensity of depressive episodes as bipolar disorder (type 1) but tends to experience hypomanic rather than manic episodes (less intense than full-blown manic episodes)
• Dysthymia


  Person experiences depressive symptoms for much of the time but never quite reaches the threshold for a diagnosis of a depressive episode
• Cyclothymia


  Person experiences numerous hypomanic episodes and depressive symptoms within a two-year period, with little respite between episodes and symptoms more of the time than not
• Beck Depression Inventory


  Measure of depression
• Diagnosis of depression


  1. Detailed clinical interviews

  2. Use of interview schedules based on CD/DSM guidelines

  3. Gather qualitative data

  4. Use psychometric tests to gauge range, intensity and duration of symptoms

  5. Gather quantitative data
• Nomothetic approach


  Psychometric tests as a good example
• Beck Depression Inventory (BDI)


  • Psychometric test created by Aaron Beck
  • Can only be used with people over 13
  • Focuses on last 2 weeks
  • 21 items (e.g. self-dislike, pessimism, indecisiveness)
  • Takes 5-10 minutes to complete
• Beck Depression Inventory


  • Helps determine severity of symptoms
  • Score of 14-19 is common in mild depression
  • Score of 20-28 is moderate depression
  • Score of 29-43 is severe depression
• The BDI test was designed to be used by qualified health professionals
• If you complete the test online and feel like you need some support, see the advice at the end of this chapter
• Questions from the Beck Depression Inventory

  • Sadness
  • Pessimism
  • Past failure
• Beck Depression Inventory


  • Evidence suggests it is reliable and valid
  • Excellent test-retest reliability
  • Positively correlated with other well-respected depression tests
  • Quick to administer
  • Provides precise and accurate data
• The BDI is widely used by researchers and clinicians to assess the efficacy of treatments such as antidepressants and cognitive-behavioural therapy (CBT)
• The speed at which the BDI can be completed makes it particularly popular as time is often extremely limited in real-world settings
• Completing the BDI


  1. Semi-structured interview with a doctor

  2. Doctor completes the BDI based on the participants' answers
• Psychometric tests like the BDI collect purely quantitative data


  Aim to decide the extent to which a person's symptoms match agreed definitions of depression
• High levels of agreement between independent raters were found for diagnoses of bipolar disorder (type 1) (84%) and recurrent depressive disorder (74%)
• Questionnaires that include many items formatted in a similar way (rating scales) can lead to a response set where people give the same answer to a whole set of questions, without really considering their answers
• In many low-to-middle-income countries (LMICs) people may be more likely to report somatic (bodily) symptoms such as aches and pains