In this way, a stressor may produce long-lasting effects on mood, producing many episodes apparently unlinked to any stressor, rather than being linked in a simple stimulusresponse fashion to a single episode. This possibility may also explain why it has been reported to be more difficult to associate, later episodes

in BPD with discrete, identifiable stressors—an important assumption for the kindling model.99 Such trends, if valid, would seem to indicate that long-term mood changes in BPD patients, although not cyclic, are still highly organized compared with normal controls, and can be Inhibitors,research,lifescience,medical characterized by the presence of a low-dimensional chaotic process. Traditional steady-state Inhibitors,research,lifescience,medical or simple oscillatory models of mood disorders cannot account for such findings. Consequently, the study of more dynamically complex oscillatory systems is required to understand the Carboplatin purchase relevant pathogenic mechanisms and perhaps

pointing toward new, dynamically oriented treatment strategies.104 Heiby and colleagues noted that mood fluctuations in chronically depressed persons were more regular than those Inhibitors,research,lifescience,medical observed in healthy subjects.105 This finding led to the maladaptive, determinism hypothesis which associated illness with regularity or low complexity, and health with high complexity and more noise. Additional analysis using the methods in nonlinear dynamics led to Inhibitors,research,lifescience,medical different multi-scale structure in the activity data. Recent study on probability distributions of human activity signals revealed a universal distribution with a long tail.106 Inhibitors,research,lifescience,medical Regardless of the individual’s daily activity, exogenous conditions, phase of the circadian rhythm and average activity, there exists an invariant structure. These distributions of activity data obtained from healthy controls collapse to a universal distribution. However,

alteration in the probability distribution of the activity has been reported for patients with depression and for such patients the characterizing parameter of the isothipendyl probability distribution is significantly lower than in healthy controls.106 Scaling behavior of amplitudes at multiple timescales of activity data has also been reported107 and such behavior distinguished patients with bipolar disorder from healthy controls. In addition characterizing parameters of the scaling behavior are found to be correlated with the suicidal thinking in MDD.108 Conclusion The present article has come about as a sort of “diary” of the scientific journey that the authors started as collaborators some years ago.