February 2010  << Back  

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Chronotherapeutics for Affective Disorders: A Clinician’s Manual for Light and Wake Therapy

Richard Balon, MD

Wayne State University, Detroit, MI, USA

By Anna Wirz-Justice, Francesco Benedetti, and Michael Terman; S. Basel, Switzerland; Karger AG; 2009; ISBN 978-3-8055-9120-1; pp 116; $48 (paperback).

Psychiatry and the rest of medicine have been obsessed with finding and applying “noninvasive” treatment methods. At times—especially in psychiatry—the term “noninvasive” is a code word for “anything but medication.” One such treatment, although not completely noninvasive, is light. Some of light’s effects on the body and psyche have been known for centuries. As the authors of Chronotherapeutics for Affective Disorders, Drs. Wirz-Justice, Benedetti, and Terman, write in the foreword to their book, “Light is our source of energy, of warmth, of spiritual and emotional sustenance” (p ix). They also point out that “Light is the major synchronizer of the biological clock.”

We are all exposed to the 24-hour rhythm of wakefulness and sleep. Our own endogenous circadian rhythm set by the biological clock in hypothalamic suprachiasmatic nuclei (SCN) is usually a bit longer than 24 hours. It is synchronized to the solar cycle by the retinal light input to the SCN (p 5), our master pacemaker (p 5). Light is a much more potent “zeitgeber” (synchronizing agent) than social zeitgebers, such as the alarm clock. Exogenously administered melatonin could be another major zeitgeber. Degrees of periodicity occur in affective or mood disorders, ranging from seasonal periodicity (winter depression) and rapid cycling to the diurnal variation of mood and early morning awakening. Findings in the scientific literature “point towards increased variability in day-to-day rhythms, low circadian amplitude, and abnormal circadian timing—either too early or too late” (p 5). Rhythmic stability appears to be crucial for a stable and euthymic mood (p 13). Synchronizing impaired circadian rhythms and inducing sleep can be helpful to treat some disorders, namely the mood disorders. Synchronizing these rhythms is the basis of chronotherapeutics. Psychiatric chronotherapeutics has been defined as “controlled exposure to environmental stimuli that act on biological rhythms in order to achieve therapeutic effects in the treatment of psychiatric disorders” (p 13).

In 15 chapters, this slender volume reviews everything clinicians really need to know about chronotherapeutics. The chapters cover topics such as individual chronotherapeutic elements (light, wake therapy = total or partial sleep deprivation and sleep phase advance), integrative chronotherapeutics (combinations of light, wake therapy, and sleep phase advance), inpatient procedures, practical details for wake therapy (eg, which patients are suitable, medication allowances, contraindications, what to tell the patient, and setting and structure for the night spent awake during sleep deprivation or sleep phase advance), practical details for light therapy (criteria for light box selection, using the light box, side effects of light therapy, cautionary notes about bright light exposure), outpatient treatment strategies, range of chronotherapeutic indications, light therapy for children and adolescents, light and wake therapy for older patients, the visually impaired, endogenous and exogenous melatonin, drugs that affect rhythms (ramelteon, antidepressants, lithium, caffeine, modafinil), social rhythm therapy, and, finally, chronobiology in everyday life (knowing your chronotype; timing of school and work schedules vs sleep; light and the built environment: implications for architecture).

The book also includes 7 appendices: 1. Morningness-eveningness self-assessment questionnaire (chronotype) with scoring and interpretation; 2. Personal Inventory for Depression and SAD (diagnostic status with scoring and interpretation); 3. 25-item expanded Hamilton Depression Rating Scale with atypical symptoms (current level of depression) with scoring and interpretation; 4. 6-item Hamilton Depression Rating Scale, core symptoms (for monitoring short-term changes); 5. Daily sleep and medication logs, and mood and energy ratings; 6. Chronotherapeutics information for outpatients and clinicians following hospital discharge; and 7. Center for Environmental Therapeutics clinical assessment tools (description of what the packet contains).

The chapters are informative, well structured, and easy to read. They are filled with useful information and numerous graphs, pictures, and photos (eg, light boxes). Some of the information may not be useful universally. I cannot imagine many US inpatient facilities applying chronotherapeutics because here, inpatient treatment is often a rescue operation for patients dangerous to themselves or others. I found interesting the note on “dark therapy” for manic patients and the pilot study of amber-colored glasses for manic patients with sleep-onset insomnia (It helped!—p 21). The chapters on practical details of wake and light therapy are especially useful. The book also discusses the range of chronotherapeutic indications: antepartum depression, premenstrual dysphoric disorder, bulimia nervosa, attention-deficit/hyperactivity disorder, dementia (improved sleep, quiescence), Parkinson’s disease (for mood-associated changes, although the utility of wake therapy is controversial and caution is recommended), and shift and jet lag disturbances. The discussion of light and wake therapy in older patients notes that many of these patients live with extremely dim room lighting and are less likely than young people to go outdoors during the day. The chapter on children and adolescents describes the biological clock shift forward during adolescence, an issue that may complicate depression and sleep disorder treatment. The chapter on visually impaired patients mentions possible partial reduction of melanopsin-containing ganglion cells in glaucoma patients, which may affect both circadian and extracircadian (eg, papillary reflex) nonsensory visual function. These patients have lower plasma melatonin levels and decreased light sensitivity (reduced melatonin suppression after light exposure) (pp 65-66). The chapter on melatonin is interesting and informative, eg, who would know that “the potency of exogenous melatonin increases when the patient assumes a recumbent posture, as on the sofa or in bed. Lying down itself induces distal vasodilatation and sleepiness.” And that lithium lengthens the intrinsic period of the circadian pacemaker in the SCN and by acting on retinal photoreceptors reduces light sensitivity…and beta-blockers diminish or totally suppress pineal melatonin secretion (p 72).

One issue I would have liked to have seen addressed in this volume was the combination of chronotherapeutics and psychotherapies, namely cognitive-behavioral therapy—although, in all fairness, the book briefly mentions that interpersonal social rhythm therapy used in bipolar disorder does not incorporate structured light exposure. Maybe this issue should be the focus of future research in chronotherapeutics. Nevertheless, the book is very practical, clinically oriented, and will be appreciated by anybody interested in chronotherapeutics in general and light therapy in particular. Also, clinicians treating complex cases of mood disorders will find it useful. It is worth buying.