Approach
Depression is the most common psychiatric disorder in the general population; the majority of people with depression will present initially to primary care.[124][125] The initial diagnosis may be missed in as many as 50% of people with depression in this setting.[126][127]
History
Patients may present with a history of depressed, anxious, irritable, or flat mood; anhedonia; weight changes; libido changes; sleep disturbance; psychomotor problems; low energy; excessive guilt; poor concentration; or suicidal ideation.[1]
Patients with mild depression may appear to be functioning normally, but this requires considerably increased effort.[1] Fatigue and sleep disturbance are common features of depression. Psychomotor disturbances, and delusional (or near-delusional) guilt, are much less common but indicate greater overall severity when present.[1] Some patients emphasise somatic complaints rather than feelings of sadness.[1]
Patients may report psychotic symptoms such as delusions or hallucinations.[1][2]
Patients often have a personal or family history of depression. Enquire about the patient's response to any past psychiatric treatments (including pharmacological and non-pharmacological treatments), any history of psychiatric hospitalisation, and any emergency department visits for psychiatric illness.[128]
Some patients will have experienced stress, trauma, or loss. Clinicians should use open-ended, empathic questions when enquiring about a patient’s trauma history.[128] Patients may not share details of childhood physical or sexual abuse unless specifically asked.[128]
In older patients, depression can present as diminished self-care, somatic complaints, psychomotor retardation, irritability, and apathy. These patients may also present with severe cognitive disturbance (memory deficits) as a result of the depression.[31] Older patients may also be more likely to have single or multiple comorbidities that contribute to the development of depression (e.g., malaise from medical illness or side effects of non-psychiatric medications).[11]
Risk of death by suicide is increased substantially, with an almost 20-fold increase in risk compared to the general population.[34] Suicide risk mitigation is critical, especially as the risk may increase early in treatment. Routinely asking patients about suicidal ideation and reducing access to lethal means (especially firearms) can reduce the risk of suicide.[129] See Suicide risk mitigation.
Substance use is common in people with depression.[38][104] Enquiry should should include assessment of alcohol, tobacco, recreational drugs, and any misuse of prescribed or over-the-counter medications.[128]
Enquire about other psychiatric and non-psychiatric diagnoses. Some physical illnesses may cause symptoms that mimic depression (e.g., hypothyroidism, Cushing's disease). Depression may also affect a patient’s ability to adhere to treatment for a physical illness.
Examination
There are no definitive findings of depression on physical examination. Many patients will have a depressed affect. Some will have downcast gaze, furrowed brow, psychomotor slowing, speech latency, and expressions of guilt or self-blame.
The physical examination and cognitive screening may be useful in ruling out common conditions that are often confused with depression (e.g., hypothyroidism, dementia) and in looking for commonly co-occurring illnesses (including obesity, cancer, stroke).
Depression screening
Commonly used screening tests include the Primary Care Evaluation of Mental Disorders (PRIME-MD) and 9-item Depression Scale of the Patient Health Questionnaire (PHQ-9) for adults in primary care and the Edinburgh Depression Score for Postnatal Depression for use in the perinatal period.[130][131] Edinburgh Postnatal Depression Scale Opens in new window Several diagnostic tools are available for older adults, such as the Geriatric Depression Scale and, when cognitive impairment is prominent, the Cornell Scale for Depression in Dementia. [ Geriatric Depression Scale Opens in new window ] Cornell Scale For Depression in Dementia Opens in new window
Screening tools validated in an appropriate language for the patient may be required.
The US Preventive Services Task Force recommends that primary care practices screening adults should have systems in place that ensure positive screening results are followed by accurate diagnosis, effective treatment, and careful follow-up.[132]
Depression diagnosis
To ensure diagnostic accuracy, physicians should apply International classification of diseases, eleventh edition (ICD-11) or Diagnostic and statistical manual of mental disorders, fifth edition, text revision (DSM-5-TR) criteria to all patients suspected of having depression or who have a positive screening test for depression. Determining whether the episode is mild, moderate, or severe, with or without psychosis, informs treatment decisions. See Criteria. Subthreshold (minor) depression is not defined in DSM-5-TR, but may apply to those with 2-4 depressive symptoms, including either sad mood or anhedonia, for at least 2 weeks.[5][6]
For patients with dementia who might not readily be able to recognise or describe symptoms due to cognitive impairment, clinical assessment is essential in case finding, and can be supported by the use of a variety of diagnostic tools.[133] Specific structured diagnostic assessments for older people are available and should be used instead of the PRIME-MD or PHQ-9: for example, the Geriatric Depression Scale or, for older people with cognitive impairment, the Cornell Scale for Depression in Dementia. [ Geriatric Depression Scale Opens in new window ] Cornell Scale For Depression in Dementia Opens in new window Physicians can use the PHQ-9 to score current depression severity and to follow up treatment response.
Tests
Depression is a clinical diagnosis. There are no diagnostic tests.[134] Simple laboratory tests should be performed in the work-up to exclude other causes of depression symptoms. Initial tests include thyroid function tests, metabolic panel, and full blood count. Serum vitamin B12 and folate levels, and 24-hour urinary cortisol may also be informative.
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