Disorders that can cause depressive symptoms

Depressive symptoms are a feature of many disorders, including depressive disorders (eg major depression) and bipolar disorder.

Depressive symptoms cause varying degrees of functional impairment. The main depressive symptoms are low mood, or a loss of interest or pleasure in activities. Other depressive symptoms include:

  • somatic symptoms
    • changes to weight
    • psychomotor disturbance
    • fatigue and sleep disturbance
  • psychological symptoms
    • diminished concentration
    • low self-esteem
    • excessive guilt
    • feelings of hopelessness and helplessness
    • irritability (may be a prominent symptom in children)
  • suicidal thoughts or ambivalence about living.

Depressive disorders are differentiated by the frequency, intensity and duration of depressive episodes, and whether the onset is related to a specific event, medical condition or substance. Major depression is the classic disorder in the group of depressive disorders; however, there are a number of differential diagnoses that should be considered.

Major depression is diagnosed if a patient has at least 5 depressive symptoms for at least 2 weeks; and at least 1 of the symptoms is either depressed mood, or loss of interest or pleasure in activities. Depressive symptoms cause marked functional impairment.

If a patient with depressive symptoms does not meet the criteria for major depression, consider subthreshold depressive disorders, such as persistent depressive disorder (dysthymic disorder).

In major depression and subthreshold depressive disorders, depressive symptoms must not be better explained by another disorder (eg bipolar disorder, psychotic disorders) or triggered by a specific event, medical condition or substance.

Depressive symptoms can be triggered by specific events, medical conditions or substances including:

  • adjustment disorder with depressed mood
  • grief
  • perinatal depression in new and expectant parents
  • seasonal affective disorder (the ‘winter blues’)
  • a medical condition—the onset or exacerbation of some medical conditions can cause depressive symptoms. Central nervous system diseases (eg multiple sclerosis, stroke, Parkinson disease, dementia, temporal lobe epilepsy, Huntington disease) are most commonly implicated; however, ischaemic heart disease, endocrine disorders (eg Cushing syndrome, hypothyroidism) or widespread inflammatory disorders (eg rheumatoid arthritis) can also cause depressive symptoms. Manage the underlying medical condition and treat the depressive symptoms as per Major depression. Patients with a severe medical condition may express realistic hopelessness for their own prospects or loss of interest in activities they can no longer pursue. It is helpful to look for reactivity in pleasurable reminiscence or for interest in the lives of friends, family or colleagues
  • premenstrual dysphoric disorder—typically, symptoms of depression and anxiety occur in the late luteal phase, remit within a few days of menstruation, are absent in the follicular phase of the cycle and recur in subsequent cycles
  • substance- or drug-induced depressive disorder—check for recent changes in drug regimens or dosage of drugs that can affect mood.

Exclude bipolar disorder as a cause of depressive symptoms. Often a patient with bipolar disorder will initially present with a depressive episode; a diagnosis of bipolar disorder can only be made once an episode of mania or hypomania occurs. Hypomania can be particularly difficult to recognise because patients rarely seek treatment during this time. Ask all patients presenting with depressive symptoms about possible prior episodes of hypomania or mania, or a family history of bipolar disorder; see Approach to diagnosing bipolar disorder in adults and young people.

Depressive symptoms in a person with personality disorder could be due to personality disorder or a co-occurring depressive disorder. Distinguish dysphoric affect of personality disorder—dysphoric symptoms that are relatively stable across situations and over a period of years (ie part of the individual’s ‘usual self’)—from distinct periods of a depressive episode; see Diagnosing personality disorder.