A client asks a nurse about the differences between major depressive disorder (MDD) and dysthymia.Which of the following responses by the nurse is accurate?

"MDD is less severe than dysthymia but lasts for at least 2 years.".

"Dysthymia is characterized by alternating episodes of mania and depression.".

"Unlike MDD, dysthymia does not impair social or occupational functioning.".

"Dysthymia is chronic and lasts for at least 2 years, but is less severe than MDD.".