Diagnosis of depression

Identifying and diagnosing depression can be challenging in primary care. There are a number of guidelines and tools to aid in distinguishing between normal emotional distress and actual clinical depression.

Screening for depression

The RACGP Redbook recommends that GPs screen people over the age of 18 opportunistically, while maintaining a high level of awareness of depressive symptoms in high-risk patients. These patients include:2

  • A family history of depression
  • Other psychiatric disorders, including substance misuse
  • Chronic medical conditions
  • Unemployment
  • Low socioeconomic status
  • Older adults following significant life events (e.g. Illness, cognitive decline and bereavement)
  • All family members who have experienced family violence
  • Experience of child abuse

While there are a variety of screening tools available the RACGP recommend asking two simple questions about mood and anhedonia, which may be as effective as more complex instruments2 and if answered in the affirmative - can lead to more detailed questioning.

“Over the past two weeks, have you felt down, depressed or hopeless?”


“Over the past two weeks, have you felt little interest or pleasure in doing things?”

Establishing a diagnosis of major depression

Assessing people with suspected depression3

When assessing a patient with depression consider the following factors:

  • Risk—assess the risk of suicide, self-harm and harm/neglect to others (especially in perinatal depression).
  • Psychosocial aspects—ask about stressful situations/events (e.g. relational, occupational, financial or legal problems; domestic violence; gambling problems).
  • Premorbid personality—assess the persons’s usual coping styles.
  • Medication—check for recent change in medication or dose (e.g. corticosteroids, beta blockers, oral contraceptives, levodopa, interferon, isotretinoin); consider withdrawal/substitution or a reduction in the dose of the suspected causative drug.
  • Bipolar disorder—check for previous manic or hypomanic episode, bipolar disorder, or family history of bipolar disorder, and assess and treat accordingly.
  • Comorbid anxiety—if onset with depression, anxiety is likely to resolve with effective antidepressant treatment. If longstanding or predating the onset of depression, treat anxiety concurrently with the depression.
  • Comorbid substance abuse—integrate the management of both problems, preferably by a team. Alcohol is a powerful depressant; drinking alcohol decreases the efficacy of antidepressants.

Severity of symptoms

Mild, moderate and severe depression tend to have very different presentations (Table 1).

Assessing the severity of symptoms in depression usually involves symptom counting. Generally this is done using ICD-101,3 or DSM3 criteria

ICD-10 criteria DSM-5 criteria
  1. Depressed mood
  2. Loss of interest and enjoyment
  3. Reduced energy leading to increased fatigability and diminished activity

    Other common symptoms are:
  4. Reduced concentration and attention
  5. Reduced self-esteem and self-confidence
  6. Ideas of guilt and unworthiness
  7. Bleak and pessimistic views of the future
  8. Ideas or acts of self-harm or suicide
  9. Disturbed sleep
  10. Diminished appetite
  1. Depressed mood
  2. Loss of interest or pleasure
  3. Significant change in appetite and weight
  4. Insomnia or hypersomnia
  5. Psychomotor agitation or retardation
  6. Fatigue or loss of energy
  7. Feelings of worthlessness or excessive guilt
  8. Impaired thinking or concentration; indecisiveness
  9. Suicidal thoughts/thoughts of death

Under ICD-10, a mild depressive episode requires the presence of at least 4 symptoms, including at least one of the first three symptoms (nos. 1–3, above); a moderate depressive episode requires 6 or 7 symptoms; a severe depressive episode is defined by the presence of at least 8 symptoms.1

Under DSM-5 a diagnosis of major depression is based on the presence the first two symptoms (nos. 1 and 2, above) with a total of at least 5 symptoms from the list. These symptoms must have been present on most days for at least 2 weeks. A diagnosis of minor depression is usually recommended when the first two symptoms (nos. 1 and 2, above) are present with a total of 2–4 symptoms from the list.4,5

Table 1. Assessing severity of depression1
Symptom cluster Mild Moderate Severe
Mood Lowered mood
Reduced joy
Reduced pleasure in things
Reduced interest in things
Reduced reactivity of mood
No pleasure in things
No interest in things
No reactivity of mood
Depressive thought Loss of confidence Feeling worthless or a failure
Hopeless, see no future
Self-reproach, guilt, shame
Consider illness a punishment
Paranoid or nihilistic delusions
Cognition Minor forgetfulness or lack of concentration Indecisiveness
Unable to make decisions
Slowed thinking, seems cognitively impaired (pseudodementia)
Somatic Low drive
Loss of interest in food
Lowered libido
Mild initial insomnia; wake 1–2 times each night
Low energy, drive
Eat with encouragement; mild weight loss
Loss of libido
Initial insomnia, wake several times a night
No energy, drive
Unable to eat; severe weight loss
No libido
Psychomotor retardation or agitation
Sleep only a few hours
Social Mild social withdrawal Apathy and social withdrawal
Work impairment
Apathy and social withdrawal
Marked work impairment
Poor self-care
Suicidality Life not enjoyable
Life not worth living
Thoughts of death or suicide
Evidence of intent to suicide (plans, attempts)

Using scales and tools

Scales and tools can help make a global assessment of a person’s depressive symptoms and may aid diagnosis, and assist with monitoring response to treatment. There are a number available that have been validated for major depression such as the Kessler 10, and the shorter Kessler 6.1 Other tools include PHQ-9 or DASS.1 For a more comprehensive list, see Depression assessment tools.


  1. Beyond Blue. Beyondblue guide to the management of depression in primary care. A guide for health professionals. 2010. http://www.beyondblue.org.au/resources/health-professionals (accessed 9 July 2013).
  2. The Royal Australian College of General Practitioners. Guidelines for preventive activities in general practice (The Red Book) 8th Edition. Melbourne: RACGP, 2012. http://www.racgp.org.au/your-practice/guidelines/redbook/ (accessed 11 February 2013).
  3. Therapeutic Guidelines Limited. eTG complete [internet]. Melbourne: 2013. http://etg.hcn.com.au/desktop/index.htm (accessed 2 May 2013).
  4. American Psychiatric Association. Diagnostic and statistical manual of mental disorders. 4th, text revised ed, 2000.
  5. American Psychiatric Association. Highlights of changes from DSM-IV-TR to DSM-5. 2013. http://www.dsm5.org/Documents/changes%20from%20dsm-iv-tr%20to%20dsm-5.pdf (accessed 16 July 2013).