Seasonal affective disorder

Winter-summer difference in post-awakening salivary α-amylase and sleepiness depending on sleep and melatonin

Winter and summer seasons are contrasted by light/dark conditions at temperate latitudes, and the negative influence of this contrast on circadian health is yet to be quantified. This field study (performed in Novosibirsk, 55°N, no daylight saving time transitions) aimed to compare post-awakening arousal state in summer and winter in subjects (N=45) on a fixed 5-workday schedule (waken up by alarm at either ∼6 am or ∼7 am). Their circadian status (by 24-h melatonin profiles) and sleep (by log data) have been previously reported. Salivary α-amylase levels (a biomarker of the sympathetic nervous system activity, or stress) and subjective sleepiness were measured immediately after awakening on Friday, at minute 0 (supine), 10, 20, and 30 (not supine). α-Amylase levels were found to be higher in winter, along with a blunted α-amylase awakening response (AAR; a decline from minute 0 to minute 10 value). Both effects were attributable mainly to the 7am group. Sleepiness levels also increased in winter, mainly due to the seasonally dependent subjects, and predictably associated with shorter, later sleep, and later melatonin circadian phase. The sleepiness and α-amylase changes did not correlate. The seasonal change in α-amylase was positively associated with the change in the amount of melatonin secreted, probably reflecting the parallelism in the noradrenergic neural control of both α-amylase and melatonin secretion. Together, higher post-awakening salivary α-amylase levels (indicating stress) and subjective sleepiness levels (indicating greater sleep need) in winter compared to summer point to a less healthy state in winter.

Amygdala response to emotional faces in seasonal affective disorder

BACKGROUND

Seasonal affective disorder (SAD) is characterized by seasonally recurring depression. Heightened amygdala activation to aversive stimuli is associated with major depressive disorder but its relation to SAD is unclear. We evaluated seasonal variation in amygdala activation in SAD and healthy controls (HC) using a longitudinal design targeting the asymptomatic/symptomatic phases of SAD. We hypothesized increased amygdala activation to aversive stimuli in the winter in SAD individuals (season-by-group interaction).

METHODS

Seventeen SAD individuals and 15 HCs completed an implicit emotional faces BOLD-fMRI paradigm during summer and winter. We computed amygdala activation (SPM5) to an aversive contrast (angry & fearful minus neutral) and angry, fearful and neutral faces, separately. Season-by-group and main effects were evaluated using Generalized Least Squares. In SAD individuals, we correlated change in symptom severity, assessed with The Hamilton Rating Scale for Depression - Seasonal Affective Disorder version (SIGH-SAD), with change in amygdala activation.

RESULTS

We found no season-by-group, season or group effect on our aversive contrast. Independent of season, SAD individuals showed significantly lower amygdala activation to all faces compared to healthy controls, with no evidence for a season-by-group interaction. Seasonal change in amygdala activation was unrelated to change in SIGH-SAD.

LIMITATIONS

Small sample size, lack of positive valence stimuli.

CONCLUSIONS

Amygdala activation to aversive faces is not increased in symptomatic SAD individuals. Instead, we observed decreased amygdala activation across faces, independent of season. Our findings suggest that amygdala activation to angry, fearful and neutral faces is altered in SAD individuals, independent of the presence of depressive symptoms.

Normalizing sleep quality disturbed by psychiatric polypharmacy: a single patient open trial (SPOT)

There is a growing interest in personalized and preventive medicine initiatives that leverage serious patient engagement, such as those initiated and pursued among participants in the quantified-self movement. However, many of the self-assessments that result are not rooted in good scientific practices, such as exploiting controls, dose escalation strategies, multiple endpoint monitoring, etc. Areas where individual monitoring and health assessments have great potential involve sleep and behavior, as there are a number of very problematic sleep and behavior-related conditions that are hard to treat without personalization. For example, winter depression or seasonal affective disorder (SAD) is a serious, recurrent, atypical depressive disorder impacting millions each year. In order to prevent yearly recurrence antidepressant drugs are used to prophylactically treat SAD. In turn, these antidepressant drugs can affect sleep patterns, further exacerbating the condition. Because of this, possibly unique combinatorial or ‘polypharmaceutical’ interventions involving sleep aids may be prescribed. However, little research into the effects of such polypharmacy on the long-term sleep quality of treated individuals has been pursued. Employing wireless monitoring in a patient-centered study we sought to gain insight into the influence of polypharmacy on sleep patterns and the optimal course of therapy for an individual being treated for SAD with duloxetine (Cymbalta) and temazepam. We analyzed continuous-time sleep data while dosages and combinations of these agents were varied. We found that the administration of Cymbalta led to an exacerbation of the subject’s symptoms in a statistically significant way. We argue that such analyses may be necessary to effectively treat individuals with similar overall clinical manifestations and diagnosis, despite their having a unique set of symptoms, genetic profiles and exposure histories. We also consider the limitations of our study and areas for further research.

The two-process model of sleep regulation: a reappraisal

In the last three decades the two-process model of sleep regulation has served as a major conceptual framework in sleep research. It has been applied widely in studies on fatigue and performance and to dissect individual differences in sleep regulation. The model posits that a homeostatic process (Process S) interacts with a process controlled by the circadian pacemaker (Process C), with time-courses derived from physiological and behavioural variables. The model simulates successfully the timing and intensity of sleep in diverse experimental protocols. Electrophysiological recordings from the suprachiasmatic nuclei (SCN) suggest that S and C interact continuously. Oscillators outside the SCN that are linked to energy metabolism are evident in SCN-lesioned arrhythmic animals subjected to restricted feeding or methamphetamine administration, as well as in human subjects during internal desynchronization. In intact animals these peripheral oscillators may dissociate from the central pacemaker rhythm. A sleep/fast and wake/feed phase segregate antagonistic anabolic and catabolic metabolic processes in peripheral tissues. A deficiency of Process S was proposed to account for both depressive sleep disturbances and the antidepressant effect of sleep deprivation. The model supported the development of novel non-pharmacological treatment paradigms in psychiatry, based on manipulating circadian phase, sleep and light exposure. In conclusion, the model remains conceptually useful for promoting the integration of sleep and circadian rhythm research. Sleep appears to have not only a short-term, use-dependent function; it also serves to enforce rest and fasting, thereby supporting the optimization of metabolic processes at the appropriate phase of the 24-h cycle.

Dawn simulation vs. bright light in seasonal affective disorder: Treatment effects and subjective preference

BACKGROUND

Studies comparing the efficacy of dawn simulation to conventional bright light for the treatment of seasonal affective disorder (in parallel groups) have yielded conflicting results. This crossover study investigated treatment outcomes and long-term treatment preference.

METHODS

Forty winter depressives were treated for a week with bright light (4.300lx for 30-45min shortly after awakening) or dawn simulation (gradually increasing light during the last 30min of sleep achieving 100lx before alarm beep, with the dawn simulator placed closer to the open eyes for a further 15min: 250lx). The depression level was self-rated using SIGH-SAD-SR.

RESULTS

Depression scores reduced similarly following bright light and dawn simulation: for 43.8% and 42.2% (medians), respectively; efficacy ratio was 23:17. The preference was also similar (21:19). Among those who preferred bright light, the most common reason was that they perceived the bright light to be more effective (19/21; it was more effective, p=0.0096; this subgroup tended to have more severe depression) and ease of use (6/21). Among those who preferred the dawn simulator, the reasons were a more "natural" action (9/19), device compactness and/or time-saving (10/19) and in 4 cases where bright light caused eyestrain.

LIMITATIONS

Not overhead naturalistic light for dawn simulation, self-rating of depression.

CONCLUSIONS

Dawn simulation is similarly effective to bright light in the treatment of winter depression. Patients with more severe depression tended to report greater improvement with bright light; in such cases, this would outweigh the non-clinical advantages of dawn simulation.

Bright light for weight loss: results of a controlled crossover trial

OBJECTIVE

To investigate whether bright light treatment can reduce body mass in overweight subjects irrespective of their seasonal (= light) dependence.

METHODS

A crossover, placebo-controlled, randomized clinical trial was performed between November and April in Novosibirsk, Russia (55° N). The trial comprised a 3-week in-home session of morning bright light treatment using a device of light-emitting diodes and a 3-week placebo session by means of a deactivated ion generator, separated by an off-protocol period of at least 23 days. The number of placebo and light sessions was matched with respect to season. Data were obtained from 34 overweight women, aged 20-54 years, 10 were seasonal-dependent according to the Seasonal Pattern Assessment Questionnaire. Weekly measures included body weight, percentage body fat by bioimpedancemetry, and subjective scores (appetite, mood, energy levels).

RESULTS

Motivation and expectation towards weight loss were similar for the two intervention sessions. With light, compared to the placebo session, weight did not reduce significantly, but percentage fat, fat mass, and appetite were significantly lower (average fat reduction 0.35 kg). The latter two results remained significant after excluding seasonal-dependent subjects from the analysis. Irrespective of the type of intervention, seasonal-dependent subjects had greater weight and fat mass changes during treatment (decline p < 0.036) or between sessions (regain p < 0.003). Photoperiod (p = 0.0041), air temperature to a lesser extent (p = 0.012), but not sunshine (p = 0.29) was associated with the weight change (greater weight reduction if the second session was in spring).

CONCLUSION

Morning bright light treatment reduces body fat and appetite in overweight women and may be included in weight control programs.