Alterations of biological rhythms are well recognized to play a crucial role in the origin and maintenance of depression, but little is known about the profile of circadian rhythms at a premorbid age in adult depressed patients. The present study was aimed at investigating the association, if any, of depressive disorders with biological and behavioural rhythm modifications both at the time of observation and at an earlier age than the clinical onset of depression. The hypothesis was that such modifications could be an early biological index of vulnerability to the illness.

One hundred and seventy-eight patients affected by DSM-IV Major Depressive Disorder were examined/observed, compared to a group of 178 matched healthy subjects. All the included subjects were asked to fill in a retrospective questionnaire reporting time of awakening and falling asleep and time of subjective peaks of appetite, energy and cognitive function during “Adolescence” (12–15 years), “Youth” (16–20 years) and “Present condition” periods.

An advance of awakening time by about 20 minutes during “Adolescence” was reported in the depressed subjects as compared to the controls. Awakening is also reported as significantly (P < 0.001) advanced by about 36 minutes during “Youth” in depressed patients, while time of falling asleep at the same age in the patients group shows 19 minutes delay. Regarding “Present condition” an advance of awakening time (33 minutes) in depressed patients was reported, in association with a delay of the subjective peak of cognitive functioning (62 minutes).

Depressed patients show clear-cut differences in sleep pattern as compared to controls, consisting in a constant and significant advance of awakening time, while the time of sleep onset never reaches any statistical difference between the groups throughout ages.

The results are consistent with the hypothesis that early alterations of the general circadian profile can contribute to the onset of adult life Major Depressive Disorders.

Since bipolar affective disorder has been recorded, clinicians treating patients with this disorder have noted the cyclic nature of episodes, particularly an increase in mania in the spring and summer months and depression during winter.

The aim of this study was to investigate seasonality in symptom onset and service admissions over a period of 10 years in a group of patients (n= 359) with first-episode (FE) mania (n= 133), FE schizoaffective disorder (n= 49) and FE schizophrenia (n= 177).

Patients were recruited if they were between 15 and 28 years of age and if they resided in the geographical mental health service catchment area. The number of patients experiencing symptom onset and service admission over each month and season was recorded.

In terms of seasonality of time of service admission, the results indicate a high overall seasonality (particularly in men), which was observed in both the schizoaffective and the bipolar groups. In terms of seasonality of symptom onset, the results indicate that seasonality remains in the male bipolar group, but other groups have no seasonal trend.

This provides further evidence that systems mediating the entrainment of biological rhythms to the environment may be more pronounced in BPAD than in schizoaffective disorder and schizophrenia. These results may help facilitate the preparedness of mental heath services for patients at different times of the year.