SYMPOSIA

Abstracts of the Invited Speakers
Psychotropic drugs effecting biological rhythm (Chronobiotics)
Elif Oral
Department of Psychiatry, Faculty of Medicine, Atatürk University, Erzurum, Turkey
E-mail: oralelif@yahoo.com
Biological clocks such as circadian, ultradian, and infradian rhythms have their own organizations, independently from environmental
conditions. Although there is biological sustainability, psychiatric disorders and also psychotropic medications have important effects
on the synchronization of biological clocks. Various biological mediators such as glutamate, γ aminobutyric acid, histamine, dopamine,
acetylcholine, serotonin and their receptor systems take on the mediation of inner clocks via psychotropic drugs.
Histaminergic activity is highly increased during wakefulness. H1 antagonists, generally increase Slow-Wave Sleep and stage 2 sleep
and reduce rapid eye movement sleep. Diphenhydramine can cause subjective sedation and decreased sleep latency with no effect
on memory or learning processes. The long elimination half-lives of these drugs can result in next-day sedation and impairment of
psychomotor and cognitive function the next morning.
Benzodiazepines shorten sleep-onset latency, increase total sleep time and stage 2 sleep, and suppress rapid eye movement sleep and
slow-wave sleep. The risk of rebound insomnia is greatest with rapid elimination of benzodiazepines.
About 65% of major depressive disorder patients report sleep complaints. Based on polysomnography studies, sleep architecture is
estimated to be disturbed in up to 90% of depressed patients. Except desipramine, all TCAs block H1 and α1 receptors to varying degrees.
As a general rule, the noradrenergic TCAs (e.g. desipramine, protriptyline) are considered ‘activating’. These agents have a tendency to
increase sleep-onset latency as well as to decrease total sleep time, associated with an increase in wake time after sleep onset. Paroxetine
and fluoxetine clearly suppress REM sleep, both among healthy volunteers and depressed patients. Compared to other SSRIs, citalopram
may be less activating and therefore less likely to disrupt sleep continuity.
Lithium and valproate have many acute, subacute, and chronic effects on systems, at the cellular and molecular levels. Lithium treatment
modifies circadian rhythms in humans and in most animals, primarily by lengthening the period of the cycle.
Most of the sleep-promoting effects of antipsychotic drugs have been related to their potency to antagonize α adrenergic, histaminergic,
or cholinergic neurotransmission. Among classical antipsychotics, drugs having these properties, such as phenothiazines and
thioxanthenes, are clearly sedative and promote sleep. Among atypical antipsychotics, drugs having this pharmacodynamics profile are
olanzapine, clozapine, and quetiapine. Clozapine and olanzapine increase total sleep time and sleep efficiency and have no clear-cut
effect on REM sleep.
Key words: Psychotropic drugs, biological rhythm
Bulletin of Clinical Psychopharmacology 2011;21(Suppl. 2):S88
A general overview of chronotherapeutics
Yavuz Selvi
Department of Psychiatry, Yuzuncu Yil University, Van, Turkey
E-mail: dryavuzselvi@yahoo.com
The sleep-wake cycle occurs because of the two independent but additive processes, homeostatic sleep and circadian processes. Circadian
rhythms play a significant role in regulating daily behavioral rhythms, cortisol and melatonin secretions, body temperature, sleep/wake
cycle, alertness and performance levels. Disrupted synchronization of circadian rhythms impairs cognition, behavior and mood with
deterioration of sleep-wake cycle and social rhythms. Some clinical and neurobiological findings suggest circadian dysregulation in
depressive patients. Diurnal variation of mood, early morning awakening, phase advance for body temperature, cortisol, latency of the
first phase of REM sleep for several other hormones and monoamines or their metabolites and sleep disturbances are core features of
depression that have linked depression with circadian rhythm function (1,2).
Clinical and neurobiological findings have promoted the idea that the restoration of circadian rhythm could have an antidepressant effect.
The term, chronotherapeutics, refers to biologically-based, non-pharmaceutical and clinical interventions that act on disrupted biological
rhythms in order to achieve therapeutic effects in the treatment of psychiatric conditions (3). Delayed therapeutic effects, tolerability,
side effects, and drug–drug interactions of pharmacotherapeutic agents, as well as pregnancy and the postpartum period, prevent
antidepressant use and promote chronotherapeutic interventions.
S88 Bulletin of Clinical Psychopharmacology, Vol: 21, Supplement: 2, 2011 - www.psikofarmakoloji.org