Rhodiola Rosea Revelations

Rhodiola Rosea Effects On Central Nervous System

In this chapter of the Rhodiola Rosea Phytomedicinal Overview, doctors Richard Brown, Patricia Gerbarg and Zakir Ramazanov explore Rhodiola Rosea Effects On the Central Nervous System. In this chapter, we learn the fundamentals of how R. rosea appears to work in our brains and our nervous system.

The fundamental causes of both the benefits of rhodiola and the side effects of rhodiola derive from these effects on neurotransmitters along multiple neuronal pathways. Many studies are referenced in this section, so don’t hesitate to visit the credits and references page listed at the end.

Rhodiola Rosea Effects On Central Nervous System

The systematic study of the pharmacological effects of R. rosea, begun in 1965, found that small and medium doses had a stimulating effect, such as lengthening the time mice swim and remain on vertical perches to the limit of their abilities. In contrast, larger doses were found to have more sedative effects. Small doses increased the bioelectrical activity of the brain, presumably by direct effects on the brainstem ascending and descending reticular formation.23-26,38,39,41 Further studies showed that medium range doses, unlike tranquilizers, enhanced the development of conditioned avoidance reflexes in rats and facilitated learning based on emotionally positive reinforcement.18,42-46 Overall, in small and medium doses, R. rosea stimulated norepinephrine (NE), dopamine (DA), serotonin (5-HT), and nicotinic cholinergic effects in the central nervous system (CNS). It also enhanced the effects of these neurotransmitters on the brain by increasing the permeability of the blood brain barrier to precursors of DA and 5-HT.2,23,42,46-49

Rhodiola Rosea Phytomedicinal Overview

Possible Actions of Rhodiola Rosea

In comparing studies of R. rosea, Asian ginseng (Panax ginseng C.A. Mey., Araliaceae), meclofenoxate (centrophenoxine), piracetam, citicholine, and other nootropics (substances that enhance cognition, protect the brain, and have low toxicity and few side effects), Petkov and colleagues noted that all of these agents enhance learning and memory in animal models and increase 5-HT levels in the frontal cerebral cortex.46-50 Diagram 1 illustrates the possible effects of R. rosea on neurotransmitters in multiple neuronal pathways.51 Starting in the brain stem, R. rosea promotes release of NE, 5-HT, and DA in ascending pathways that activate the cerebral cortex and the limbic system.2,49,50 Consequently, the cognitive (thinking, analyzing, evaluating, calculating, and planning) functions of the cerebral cortex and the attention, memory, and learning functions of the prefrontal and frontal cortex are enhanced. Other neuronal systems also contribute to the many aspects of memory: encoding, sorting, storage, and retrieval. For example, the cholinergic system uses the neurotransmitter acetylcholine (Ach) and contributes to memory function via pathways ascending from the memory storage systems of the limbic system to various areas of the cerebral cortex (memory retrieval). Agents that block Ach suppress the activity of these ascending pathways and interfere with memory. R. rosea reverses this blockade.49,50 The deterioration of these systems with age results in age-associated memory loss.52 R. rosea may prevent or ameliorate some age-related dysfunction in these neuronal systems.

Rhodiola Rosea As An Antioxidant

As an antioxidant,53-55 R. rosea may help protect the nervous system from oxidative damage by free radicals. Stress interferes with memory functions and, over time, causes deterioration in memory systems. In addition to enhancing cognitive functions, learning, and memory by stimulating NE, DA, 5-HT, and Ach neuronal systems, R. rosea may exert positive effects on memory and cognition by improving resistance to physical and emotional stress. Thus, the dual action of cognitive stimulation and emotional calming creates benefits for both immediate cognitive and memory performance and for the long-term preservation of brain functions.

The Psychostimulant Effects of Rhodiola Rosea

The psychostimulant effects of R. rosea were studied in 53 healthy subjects and 412 patients with neuroses and asthenic syndromes (of both functional and organic origin).56-58 Symptoms of asthenia (fatigue, decline in work capacity, trouble falling asleep, poor appetite, irritability, and headaches) responded favorably to R. rosea 50 mg three times a day. Treatment durations ranged from 10 days to 4 months. The asthenic states included both psychiatric and physical causes, for example, following influenza or other illness. In an open study of 128 patients aged 17-55 years, R. rosea alleviated fatigue, irritability, distractibility, headache, weakness and other vegetative symptoms in 64 percent of cases.57 Improvement was assessed by psychological testing and work productivity.

In 1869 Beard coined the term “neurasthenia” to include various forms of nervous asthenia. Controversy over this term has centered on the overlap of symptomatology and co-morbidity with other conditions (e.g., depression, neuroses, somatoform disorders, and chronic fatigue syndrome). Although this diagnosis has fallen out of favor in the United States and no longer appears in The Diagnostic and Statistical Manual of the American Psychiatric Association (DSM-IV),59 it is still widely used throughout the world.60-63 Neurasthenia is defined by the World Health Organization in the International Classification of Diseases (ICD-10)64 as:

  • either persistent and distressing feelings of exhaustion after minor mental effort, or persistent and distressing feelings of fatigue after minor physical effort;
  • accompanied by one or more of the following symptoms: muscular aches or pains; dizziness; tension headaches; sleep disturbance; inability to relax; and irritability;
  • inability to recover through rest, relaxation, or enjoyment;
  • does not occur in the presence of organic mental disorders, affective disorders or panic, or generalized anxiety disorder.

Rhodiola Rosea’s Impact On Mental Performance

In an open study 27 healthy students, physicians, and scientists aged 19-46 years were given 10 drops of R. rosea tincture (equivalent to 100-150 mg R. rosea extract) once or twice a day for 2-3 weeks, beginning several days before intense intellectual work, such as final exams.58 The extract improved the amount and quality of work and in all cases prevented asthenic decompensation (loss of work capacity due to fatigue). A series of studies using a proofreading test showed that a one-time dose of R. rosea did not significantly increase the number of symbols corrected, but very significantly decreased the percent of errors made, particularly over an 8-hour period.65,66 Positive results found in the studies of proofreading tests were based on 300 mg/day or more. In medical treatments, the usual doses are 200-600 mg/day. R. rosea increased intellectual capacity (particularly by improving perception and processing of information) to a greater degree than an extract of eleuthero, formerly called Siberian ginseng (Eleutherococcus senticosus Rupr. et Max., Araliaceae).18

The decrease in physical and mental performance of physicians on prolonged night call is well known. Low dose (170 mg/day) R. rosea extract was given to 56 young, healthy physicians on night call.18 The effect was measured as total mental performance calculated as “Fatigue Index.” The tests reflected an overall level of mental fatigue involving complex cognitive functions, such as associative thinking, short-term memory, calculation, concentration, and speed of audio-visual perception. These parameters were tested before and after night duty during three periods of two weeks each in a double-blind crossover trial. A statistically significant improvement in mental performance tests was observed in the treatment group (R. rosea) during the first two-week period. However, at 6 weeks the effect appeared to be lost. No side effects were reported. These results suggest that R. rosea extract can reduce fatigue under certain stressful conditions for some period of time. Possible reasons for the loss of efficacy over time may be the low dose used, the crossover design, or the overall length of night duty with increased fatigue by weeks 5 and 6.

Spasov and colleagues compared 100 mg/day R. rosea extract (SHR-5, Swedish Herbal Institute, Goteborg, Sweden; standardized to 3 percent rosavin and 0.8 percent salidroside) with placebo in a double-blind 20- day study of 60 Indian medical students studying in Russia during their final exam period.38 Despite the low dosage, investigators found significant improvements in general well-being, physical fitness, mental fatigue, final exam grades, and coordination, but not in some aspects of cognitive functioning in students taking R. rosea extract compared to placebo.

In a double-blind placebo-controlled study of 60 foreign students at a Russian high school, administration of a R. rosea extract (660 mg/day of a preparation named Rodaxon) resulted in an increase in physical (velergometric) work capacity, coordination, kinesthetic sensitivity, and general well-being along with a decrease in psychic fatigue and situational anxiety.39 Unfortunately, this study provides no information on the amount of R. rosea in the Rodaxon preparation, which is commercially unavailable.

R. Rosea for Helping Cognitive Dysfunctions

R. rosea was beneficial in post-traumatic and vascular lesions of the brain. It was especially effective in combination with piracetam for patients with marked cognitive dysfunction.56 However, it did not reduce manic symptoms and could worsen paranoid states. In one study of more clearly depressed patients, R. rosea in combination with tricyclic antidepressants (TCAs) produced significant improvement in the majority of cases and decreased side effects of the TCAs.67 Ultimately, some of these patients were able to respond to R. rosea alone.

Antipsychotic medications used in large doses over many years to treat schizophrenic patients sometimes affect the dopaminergic nerves in the basal ganglia, the same nerves that are damaged in patients with Parkinson’s Disease. When these nerves are compromised, patients develop a constellation of “Parkinsonian” symptoms, including stiffness, tremors, bradykinesia (slowed movements), and others. Anticholinergic medications have been used to relieve these symptoms when they are caused by antipsychotic medication; however, they sometimes fail to help. In schizophrenic patients whose anticholinergic medications had failed to relieve Parkinsonian symptoms, R. rosea was found to be of benefit.56,68

Rhodiola Rosea And Your Emotions

R. rosea may affect emotional tone by influencing neurotransmitter monoamine levels (NE, DA, 5-HT) in nerve tracts involved in the regulation of mood, anxiety, and emotion in the amygdala, hippocampus, hypothalamus, and midbrain. The stimulation of nicotinic cholinergic activity in the emotional circuits of the limbic system (in the temporal lobe) may also contribute to these effects. Alterations in monoamine levels underlie this complex spectrum of psychotropic activity: stimulating, tranquilizing, anti-stress, and antidepressant.

The authors have found that R. rosea can help patients with depressive syndromes, mental and physical fatigue (secondary to psychiatric and medical conditions), memory loss and cognitive dysfunction from a variety of causes, sexual dysfunction, and menopausal-related disorders. Dr. Brown and Dr. Gerbarg have successfully treated more than 150 individuals with R. rosea extract (3 percent rosavin and 1 percent salidroside) and have supervised the treatment of more than 100 additional cases (See Rhodiola Rosea Clinical Case Studies).

Previous Section: Pharmacological Studies and Clinical Case Studies
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Table of Contents: Rhodiola Rosea: A Phytomedicinal Overview
Credits and References

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