Persistent Depressive Disorder

Persistent depressive disorder (dysthymia) is chronic depressed mood on most days for at least 2 years (1 year in children), with at least two additional depressive symptoms.

• Lifetime prevalence 3 to 6%; early onset (before 21) with more comorbidity and family history.
• Often superimposed major depressive episodes ("double depression").
• Comorbid anxiety disorders, substance misuse, personality disorders, chronic pain.
• High disability, high suicide risk, long duration.

• Low mood, low self esteem, hopelessness, poor concentration, fatigue, sleep and appetite change; symptom free periods under 2 months.
• Pessimism, social withdrawal, "always been this way".
• Impaired work and relationships.

• DSM-5 criteria; PHQ-9, Montgomery-Asberg scale.
• Exclude bipolar disorder (history of mania), hypothyroidism, anaemia, sleep apnoea, substance use, medication effects (beta blockers, steroids), chronic illness.
• Check TSH, full blood count, B12, vitamin D; assess suicide risk.

• Combined psychotherapy and medication is more effective than either alone; Cognitive Behavioural Analysis System of Psychotherapy (CBASP), CBT, interpersonal therapy.
• Antidepressants: sertraline 50 to 200 mg daily, escitalopram 10 to 20 mg, venlafaxine XR 75 to 225 mg, duloxetine 60 to 120 mg, bupropion XL 150 to 300 mg; trials of 8 to 12 weeks, treatment duration 2 years or more.
• Nonresponse: switch class, augment with lithium 600 to 900 mg, aripiprazole 2 to 10 mg, quetiapine XR 150 to 300 mg, T3 25 to 50 micrograms.
• Lifestyle: exercise, sleep, social activation, treat comorbidity.
• Relapse prevention with maintenance therapy.