Clinical psychology

17.1 · Free notes

Clinical characteristics of unipolar depression

Key points

• Unipolar depression is a mood disorder with depressive episodes only and no history of mania or hypomania, which distinguishes it from bipolar disorder. DSM-5 includes major depressive disorder (MDD) and persistent depressive disorder (PDD). ICD-11 lists single-episode and recurrent depressive disorder, and dysthymia.
• DSM-5 MDD requires five or more of nine symptoms during the same two-week period. At least one must be depressed mood or loss of interest or pleasure (anhedonia), and the symptoms must represent a change from previous functioning.
• The symptoms must cause clinically significant distress or impairment in social, occupational or other areas of functioning. They must not be due to a substance or medical condition, and there must never have been a manic or hypomanic episode.
• Emotional characteristics: persistent low mood, sadness or emptiness, anhedonia, feelings of worthlessness and guilt, lowered self-esteem and irritability. In children and adolescents DSM-5 allows irritable mood to replace depressed mood.
• Behavioural characteristics: changes in activity and energy such as psychomotor retardation or agitation, fatigue, sleep disturbance (insomnia or hypersomnia), appetite or weight change, social withdrawal, reduced productivity and self-harm or suicidal behaviour.
• Cognitive characteristics: poor concentration, indecisiveness, rumination, hopelessness and recurrent thoughts of death. Beck's negative cognitive triad (negative views of the self, the world and the future) and attentional bias towards negative information are also key.
• Persistent depressive disorder (DSM-5) needs depressed mood most of the day, on more days than not, for at least two years (one year in children and adolescents). It also needs at least two other symptoms. It is chronic and often less severe than MDD.
• ICD-11 depressive episode requires at least five of ten symptoms for about two weeks, with at least one from the affective cluster (depressed mood or markedly diminished interest). Severity is rated mild, moderate or severe, with or without psychotic symptoms.
• Clinicians must separate depression from normal sadness or grief using duration, severity and impairment. DSM-5 removed the bereavement exclusion, so grief can be diagnosed as depression if criteria are met.
• Women are diagnosed with depression about twice as often as men. Typical onset is in early adulthood and episodes often recur; these facts link to gender bias and comorbidity in diagnosis.
• Exam tip: in case-study questions, match each symptom to emotional, behavioural or cognitive and check the core symptom and duration rules. Use precise terms such as anhedonia and psychomotor retardation.

In more detail

• Worked diagnosis: for two weeks Sam has low mood, has lost interest in football, sleeps 12 hours a night, feels worthless and can't concentrate. That is 5 symptoms, including low mood and loss of interest, so if it impairs his life he meets DSM-5 criteria for major depression.
• PHQ-9: a nine-item questionnaire that scores each DSM-5 symptom from 0 to 3; a total of 10 or more suggests at least moderate depression, and it is widely used by GPs.
• Seasonal pattern: DSM-5 allows a 'with seasonal pattern' specifier for depression that regularly begins in autumn or winter.
• Grief and depression: DSM-5 removed the bereavement exclusion, so depression can be diagnosed soon after a loss if the criteria are met, which was a controversial change.