[Depressions with a surprising ending].

Periodicity of depressive episodes over many years, onset of depression entirely unconnected with external circumstances, or spontaneous end without a change in the patient's life situation strongly suggest and endogenous cause. The actual symptomatology alone does not provide direct evidence. The second criterion, the independent onset of an episode, may be difficult to reconstruct. However, a spontaneous and unexpected end is an impressive event and an argument for endogenicity even in cases of apparently reactive or neurotic origin.