Anxiety and sleep disorders

Anxiety is apprehension, tension, or uneasiness that stems from external stress that may be associated with the trials and tribulations of everyday living or, particularly, as a result of a traumatic life event (e.g., bereave- ment, financial losses, or divorce), or it may be devoid of any apparent cause. Anxiety is usually a normal response experienced by all people, and a certain amount of anxiety in one’s life is a necessary corollary of need-fulfilling activity, coping, and personal growth.

On the other hand, when anxiety becomes disproportionate to the causal stimulus or when no stimulus can be identified, it becomes disrup- tive, and the symptoms can interfere with a person’s ability to function effectively. At this point, the anxiety is considered pathologic and may be classified as an anxiety disorder. Approximately 7 percent of adults in the United States are affected by one of these disorders as classified by the American Psychiatric Association. They include, among others, panic disorder with and without agoraphobia, generalized anxiety disorder, obses- sive–compulsive disorder, and post-traumatic stress disorder. 1,2 Therapy is based principally on the type and degree of anxiety and should be con- ducted under the care of a physician.

Insomnia, the inability to attain restful sleep in adequate amounts, is often a transient response to the anxiety produced by stressful situations. About 30 percent of the American population experiences insomnia in some form over the course of a year, and it is a common complaint among the elderly. Insomnia is an inclusive term that can include problems in falling asleep (longer than thirty minutes), frequent awakening through the night with difficulty in immediately returning to sleep, and early morning final awakening resulting in a total sleep time of fewer than six hours. It can be transient, lasting for less than one week, or chronic if it lasts longer. The latter category may also be symptomatic of more seri- ous physiologic or psychological conditions or the use of various drugs, including alcohol. 3

Anxiety and insomnia are amenable to treatment with drugs that exert a depressant effect on the central nervous system. In many cases, the same central nervous system (CNS) depressants are used to treat both

116 Tyler's herbs of choice: The therapeutic use of phytomedicinals

Cl – Ion channel closed

Postsynaptic cell membrane resting state

Cl –

Ion channel open Postsynaptic

cell membrane activated state

Cl – Hyperpolarization

Decreased nerve transmission

Figure 7.1

A generalized model for the mechanism of action of some anxiolytic and sleep aid drugs at the GABA A receptor macromolecular complex of the postsynaptic neuronal membrane. Drugs do not bind at the GABA recognition protein but, rather, at separate recognition proteins that enhance the effect of GABA.

conditions; however, a larger dose is customarily employed to induce sleep. The agents used are referred to by a number of names, including sleep aids, sedatives, hypnotics, soporifics, antianxiety agents, anxiolyt- ics, calmatives, and minor tranquilizers. All of these terms are more or less synonymous, although, as noted, the degree of response obtained is dose dependent.

The mechanism of action for many of these drugs involves gamma- aminobutyric acid (GABA), which is the major inhibitory neurotrans- mitter in the CNS. For example, benzodiazepines, an important chemical group of drugs for treating anxiety and insomnia, potentiate GABAergic neurotransmission at all levels of the CNS. Their action,

illustrated in Figure 7.1, involves an interaction with a GABA A receptor–chloride ion channel macromolecular complex, causing an increase in the frequency of chloride ion channel opening in the postsynaptic membrane of the neuron. This, in turn, leads to membrane hyperpolarization and a decrease in the firing rate of critical neurons in many regions of the brain. Barbiturates also facilitate the actions of GABA; however, in contrast to benzodiazepines, they increase the duration of

the GABA-gated channel openings. 4 Most of the prescription drugs in

Chapter seven: Nervous system disorders 117 these categories involve some risk of overdose, tolerance, habituation,

and addiction. The herbs commonly used for their sedative effects do not suffer these drawbacks, but neither do they possess the degree of activity shown by the prescription drugs. In fact, the action of many traditional plant hypnotics is so slight as to remain uncertain.

Anxiety and sleep disorders