Biomedical subjects

T Partonen

Publications and source records attributed to T Partonen.

At least 55 records · Page 3Linked to original sources

PubMed1995

Estrogen could control photoperiodic adjustment in seasonal affective disorder.

Women are affected by winter seasonal affective disorder (SAD) more often than men. The female/male ratio is reported to range from 2:1 to 40:1 in samples of patients with winter SAD. It is suggested that this preponderance of women is based on the action of the ovarian steroid hormones estrogen and progesterone. However, the detailed mechanisms of action are not well understood to date. A new hypothesis claims that, in women with winter SAD, decreased levels of estradiol in the ventromedial hypothalamus are associated with the occurrence of atypical symptoms of depression, including increased daytime sleepiness and hypersomnia during the winter.

Animals↗

PubMed1995

Effects of exposure to morning bright light in the blind and sighted controls.

Seven blind subjects and 11 sighted controls were exposed to 3300 lux of cool-white fluorescent light for either 1 h or 15 min in the morning for 2 weeks during the winter. Serum 25-hydroxyvitamin D3 concentration, melatonin concentration in saliva, body temperature from the armpit, subjective sleepiness, and depressive symptoms were measured before and after the 2-week trial. The intervention resulted in a significant elevation in the concentration of melatonin at 21.00 hours in the healthy controls but at 23:00 hours in the blind subjects. The body temperatures measured were increased in the controls but decreased in the blind in the morning following the cessation of the intervention, and these opposite changes resulted in significant differences in the temperatures between the two groups. The decreases in the body temperature were associated with the increases in the levels of melatonin in the blind but not in the controls. Bright light administered in the morning decreased subjective sleepiness and improved mood in the healthy controls and in the blind subjects as well. The intervention had no effect on the levels of vitamin D in either of the two groups.

Adult↗

PubMed1995

The influence of comorbid disorders and of continuation light treatment on remission and recurrence in winter depression.

The objectives of this prospective study were to investigate the influence of comorbid disorders and that of continuation light treatment on remission rates and on a subsequent onset of a depressive episode in outpatients (n = 20) with winter depression. The effects of light treatment were evaluated by the structured clinical interviews and by the self-ratings of mood scored monthly for a follow-up period of 1 year. The remission rates of the patients (n = 8) who proceeded light treatment until the late winter were not significantly different from those of the patients (n = 6) who stopped treatment early during the winter. A more extensive variation in the rates during the year was observed in the former group of patients among whom the comorbid avoidant personality was more frequent, indicating an increased risk of an earlier onset of a depressive episode.

Adult↗

PubMed1994

Effects of morning light treatment on subjective sleepiness and mood in winter depression.

The effects of morning light treatment on mood, subjective sleepiness and body temperature were investigated with 13 outpatients with winter depression and 13 healthy controls. Bright light for 1 h daily for 2 weeks resulted in a significant reduction in depression ratings and evening subjective sleepiness in the patients compared with the healthy controls. Even a short 15-min exposure to light daily produced these changes.

Adult↗

PubMed1994

Effects of morning light treatment on subjective sleepiness and mood in winter depression.

Adult↗

PubMed1994

The shortening of the photoperiod may alter gene expression in winter depression.

Winter depression is characterised by recurrent major depressive episodes with a seasonal (winter) pattern. Reduced exposure to daylight due to shortening of the day has been hypothesized to trigger off the onset of a depressive episode. Daily exposures to light during the dark period have been used as the treatment of choice for winter depression. A genetic predisposition for high responsiveness to light is thought to exist in patients with winter depression. Altered gene expression may contribute to the unique sensitivity and mediate the antidepressant effects of light.

Circadian Rhythm↗

PubMed1994

Prolactin in winter depression.

Women with winter depression have low serum prolactin concentration that is independent of both season and efficient bright light treatment administered in winter. A defect of neural pathways afferent to the paraventricular nucleus may explain these findings. Estrogen is thought to play a key role in modulation of the rhythmic responses in winter depression.

Afferent Pathways↗

PubMed1994

Involvement of melatonin and serotonin in winter depression.

The phase of circadian rhythms can be shifted by exposure to light. Most patients with winter depression are suggested to have a phase delay in their circadian rhythms. The efficacy of light in treatment of winter depression is thought to be associated with the phase shifting effect of light. In addition to light, melatonin and serotonin can cause phase shifts of the rhythms. The concerted action of these indoleamines may underly the finding that light has an antidepressant effect, independently of time of day or circadian phase of an individual.

Animals↗

PubMed1994

Light treatment for seasonal affective disorder: theoretical considerations and clinical implications.

The concept of seasonal affective disorder (SAD) includes any depression whose onset is related to a certain season. Reduced environmental light is hypothesized to be the main precipitating factor of winter depression. Light treatment is used to prevent the onset of depressive episodes and to reduce depressive symptoms in patients with depression during winter months. The mechanisms of action which lead to the well-documented antidepressant response are still unknown. Several hypotheses of the pathogenesis of SAD are discussed, and the clinical practice of light treatment is reviewed.

Circadian Rhythm↗

PubMed1994

The molecular basis for winter depression.

A pulse of light is capable of inducing the circadian phase-dependent gene expression in neurons. The phase or amplitude of the circadian rhythms can be modulated by critically timed exposures to light. A significant heritability for the light-induced responses has been observed in hamsters. In humans, light has been used for treatment of the light-dependent winter depressive disorder. A genetic predisposition for high responsiveness to light may occur in patients with winter depression. The altered gene expression induced by light may account for a unique sensitivity to light and mediate the anti-depressant effect of light treatment.

Circadian Rhythm↗

PubMed1994

[Antidepressants, melatonin and seasonal depression].

Explore the source record for details and available documents.

Appetite↗

PubMed1993

Effects of light treatment on sleep structure in seasonal affective disorder.

Twelve outpatients with seasonal affective disorder (depression, winter type) were treated by 1 h of bright light exposure for five mornings. The intervention produced a significant reduction in depression scores, but no change was seen in the sleep electroencephalographic variables recorded after light treatment. Significant changes were seen, however, in ratings of subjective sleepiness. The acrophase of the circadian sleepiness rhythm was phase advanced, the mean level of the sleepiness rhythm was diminished, and the mean values of sleepiness scores were reduced at 8 and 10 a.m. This minimal influence of bright light on sleep structure is unlikely to explain the well-documented antidepressant effect.

Adult↗

PubMed1993

Frequencies of seasonal major depressive symptoms at high latitudes.

A modified depression rating scale was distributed to a sample of the adult Finnish population (n = 1000) in November 1991. No dependence on latitude (60 degrees N-70 degrees N) was seen in the occurrence of depression. The depressed subjects (n = 54) were reevaluated the following May, and four cases with seasonal affective disorder were found. The results suggest that high latitudes with large variations in the daily lightperiod may not be responsible for high prevalence of major depression with a seasonal pattern.

Adult↗

PubMed1993