The time series analysis was based on applying standard
and threshold autoregressive models of order 1 and
2 to the depression data for each patient. The authors
concluded that the existence of nonlinear mood variability
suggested a range of underlying deterministic patterns.
They cited the claims of Gottschalk et al. (1995), though
not the reply to them (Krystal 1998). They suggested that
the difference between the two models could be used
to determine whether a patient would occupy a stable
or unstable clinical course during their illness and thatthe ability to characterize mood variability might lead to
treatment innovation.