Lithium effect on temperature rhythm in psychiatric patients

Can body temperature dysregulation explain the co-occurrence between overweight/obesity, sleep impairment, late-night eating, and a sedentary lifestyle?

PURPOSE

Overweight/obesity, sleep disturbance, night eating, and a sedentary lifestyle are common co-occurring problems. There is a tendency for them to co-occur together more often than they occur alone. In some cases, there is clarity as to the time course and evolution of the phenomena. However, specific mechanism(s) that are proposed to explain a single co-occurrence cannot fully explain the more generalized tendency to develop concurrent symptoms and/or disorders after developing one of the phenomena. Nor is there a clinical theory with any utility in explaining the development of co-occurring symptoms, disorders and behaviour and the mechanism(s) by which they occur. Thus, we propose a specific mechanism-dysregulation of core body temperature (CBT) that interferes with sleep onset-to explain the development of the concurrences.

METHODS

A detailed review of the literature related to CBT and the phenomena that can alter CBT or are altered by CBT is provided.

RESULTS

Overweight/obesity, sleep disturbance and certain behaviour (e.g. late-night eating, sedentarism) were linked to elevated CBT, especially an elevated nocturnal CBT. A number of existing therapies including drugs (e.g. antidepressants), behavioural therapies (e.g. sleep restriction therapy) and bright light therapy can also reduce CBT.

CONCLUSIONS

An elevation in nocturnal CBT that interferes with sleep onset can parsimoniously explain the development and perpetuation of common co-occurring symptoms, disorders and behaviour including overweight/obesity, sleep disturbance, late-night eating, and sedentarism. Nonetheless, a significant correlation between CBT and the above symptoms, disorders and behaviour does not necessarily imply causation. Thus, statistical and methodological issues of relevance to this enquiry are discussed including the likely presence of autocorrelation.

LEVEL OF EVIDENCE

Level V, narrative review.

Influence of lithium on sleep and chronotypes in remitted patients with bipolar disorder

BACKGROUND

Lithium (Li) is the first-line treatment for bipolar disorder (BD), but its mechanisms of action remain unknown. Although the chronobiological action of Li is well documented in animals, its effects on sleep and chronotypes in remitted BD patients have never been investigated.

METHODS

OPTHYMUM is a multicenter, cross-sectional, observational study conducted in France. We compared the sleep (Pittsburgh Sleep Quality Index, PSQI) and chronotypes (Composite Scale of Morningness, CSM) of 525 euthymic adult bipolar outpatients with (n=149) and without (n=376) current Li treatment. We used a general linear mixed-effects Poisson model to correct for age, gender, BD subtype, and mood symptoms.

RESULTS

In patients with BD type I, women taking Li had significantly lower PSQI (-23% [-37; -7]), but men did not (-4% [-20; +16]). Patients with BD I taking Li had better sleep efficiency (-40% [-61; -7]) and tended to better sleep duration scores (-42% [-68; +3]). A Li effect exists in women for both sleep duration and the use of night sedation (resp. -70% [-90; -10] and -37% [-60; +0.01]) but not in men (resp. -12% [-63;+113] and +9% [-31;+72]). No such associations were observed for BD II. No lithium effect was detected in the CSM score.

LIMITATIONS

No controls for other medications but no between-group differences for sedative or antidepressant intakes.

CONCLUSIONS

Euthymic BD I patients with Li have better sleep efficiency and longer sleep duration than those without Li. Women with Li have better sleep quality, longer sleep duration and less frequent use of night sedation.

Nocturnal sweating and temperature in depression

OBJECTIVE

Patients with depression may have altered thermoregulation, such as high nocturnal core temperatures, decreased daytime sweating and subjective complaints of nocturnal sweating. We sought to compare nocturnal sweating in depressed patients and non-depressed controls, and to assess the impact of REM sleep on sweat rates.

METHOD

Nocturnal sweat rate, nocturnal temperature and REM sleep were measured during the night in 9 controls and 8 depressed subjects; 7 depressed patients were assessed during recovery.

RESULTS

The nocturnal temperature was significantly higher in depressed patients compared to controls, and decreased significantly with recovery. The nocturnal sweat rates of depressed patients did not differ significantly from those of controls, but decreased significantly with recovery. Analyses of sweat rates before, during and after REM sleep indicated a trend for the entire sample to show a decrease in sweat rates during REM.

CONCLUSION

The nocturnal sweating rates in the depressed patients suggest that impaired sweating is not the cause of the high nocturnal temperature commonly found in depressed patients.

Electroconvulsive therapy increases circadian amplitude and lowers core body temperature in depressed subjects

BACKGROUND

Reduced amplitude of the circadian temperature rhythm and elevated nocturnal body temperature normalize after successful pharmacotherapy of major depression.

METHODS

Core body temperature was continually monitored in three groups: a) 6 depressed patients before an electroconvulsive therapy (ECT) course and b) after an ECT course; and c) 6 healthy, sex-matched controls of similar age.

RESULTS

The 24-hour profile of temperature was significantly different in patients pre-ECT than in patients post-ECT or in controls. Post-ECT subjects and controls manifested 24-hour profiles similar to one another. Circadian temperature rhythm amplitude increased after ECT. The mean asleep and mean 24-hour temperatures were significantly higher in patients pre-ECT than post-ECT and controls.

CONCLUSIONS

We find that ECT restores a disrupted circadian temperature rhythm in depressed patients.

Rhythms and the pharmacology of lithium

Lithium is the treatment of choice for bipolar affective disorder (manic-depression) and is useful in other recurrent affective and nonaffective illnesses. This review discusses lithium's actions on period, phase, amplitude and coupling of biological rhythms that may relate to its therapeutic effectiveness. Alternatively, lithium might interact with environmental light to influence circadian rhythms by an action on the retina. The mechanisms responsible for lithium's chronopharmacological actions are not known, but cellular cations, phosphoinositide or adenylate cyclase second messenger systems, hormones and neurotransmitters may all be involved.

Body core temperature and depression during total sleep deprivation in depressives

Endogenously depressed patients were subjected to a total sleep deprivation (TSD) schedule of sleep-TSD-sleep-TSD. They were simultaneously treated with the antidepressant drug clomipramine. Self- and observer-rated depression was measured daily. Continuously measured rectal temperature (RT) data were available for the second TSD. It was found that a higher nocturnal minimum RT during this TSD was associated with a positive clinical response.

REM latency and core temperature relationships in primary depression

REM latency and rectal and ear canal temperature were studied simultaneously in 11 controls and nine depressed patients; seven of the patients were studied when recovered. REM latency was shorter in the depressed group compared with controls and lengthened with recovery. The nocturnal and ear canal temperatures were higher in the depressed group compared with controls and decreased with recovery. REM latency and the nocturnal rectal temperature were negatively correlated when all the nights of the depressed patients were analyzed (r = -0.44) and when all the nights of the subjects were analyzed (r = -0.44). REM latency and nocturnal ear canal temperatures were negatively correlated when all the nights of the control group were analyzed (r = -0.34). The timing of the temperature rhythm did not appear to be correlated with the REM latency.

Antidepressant tachyphylaxis

We report eleven patients in whom tachyphylaxis to antidepressants, lithium or ECT occurred. These cases are a small sample of patients we have encountered in whom an initial good response to mood regulating drugs was not sustained. We suspect that systematic studies would reveal that tachyphylaxis is a common phenomenon with antidepressant therapies.

Nocturnal temperature in affective disorder

The temperature rhythms of 9 drug-free patients with primary affective disorder were measured during depression and after recovery and compared with those of 12 normal controls. The patients had higher nocturnal temperatures and decreased 24-hour amplitudes when depressed than when they had recovered and compared to the controls. There was no evidence that the temperature minimum occurred earlier in the night in depression compared to controls. However, in 4 of 7 patients the temperature minimum occurred earlier in the night during depression compared to recovery.

Lithium treatment of hypothermia caused by electric shock

Prostaglandins have hyperthermic as well as hypothermic effects, and lithium, which inhibits the conversion of dihomogammalinolenic acid to PGE1, can produce hyperthermia. Electroconvulsive shock raises prostaglandin F in rat cerebral cortex and in the case presented here lithium normalized temperature in a patient who became hypothermic after she accidentally received an electric shock.

Lithium effects on time estimation and mood in manic-melancholic patients. A study of diurnal variations

Behavioural measurements of time experience and phenomenological self-ratings of mood-variations (Beecher's Mood Scale) have been carried out at night and on the following morning in a group of lithium-treated patients, in a group of psychiatric patients not given lithium, and in an untreated group of healthy subjects. In all the groups investigated the internal "clock" was slower in the morning than in the night. The results indicated that the internal "clock" in lithium-treated patients was slower than in the two other groups, but only at night. Mood variations from night ot morning were observed in all three groups. The group of lithium-treated patients had fewer complaints as to self-report of mood-variations compared with the other groups.