Posted by Bill LL on November 30, 2004, at 9:37:18
In reply to Re: Caffeine and Sweets for Depression? » linkadge, posted by zeugma on November 29, 2004, at 19:41:44
I have copied excerpts from a paper. The entire text is on:
The article indicates that lower doses of caffeine can have good effects, but higher doses (more than 200 mg per day) have bad effects.
This article also discusses the swimming test of mice that someone mentioned in the thread.
Orthomolecular Psychiatry, Volume 10, Number 3, 1981, Pp. 202-211
Caffeine: Psychological Effects, Use and Abuse
Sanford Bolton, Ph.D. and Gary Null, M.S.
Caffeine, probably the most widely used drug, affects the psychological state of those who consume it. Abuse results in symptoms of caffeinism which include agitation, disorientation and a syndrome which may be mistaken for anxiety/neurosis. It is a habit-forming drug in which tolerance develops. It affects sleep in a dose related manner which is dependent on the daily caffeine intake, i.e., high users have less effect. Its central nervous system stimulation can cause pleasant effects with improved attention and concentration at lower doses. At high doses, the reverse may occur. Used judiciously, it may be a useful therapy in the treatment of hyperkinetic children. These and other effects of caffeine are discussed in this review article.
Caffeine stimulates the central nervous system first at the higher levels, the cortex and medulla, and finally the spinal cord at higher doses. Mild cortex stimulation appears to be beneficial resulting in more clear thinking and less fatigue. Caffeine has been shown to improve attention in a study which simulated night driving (Leinart, 1966). The onset of the effect of caffeine occurs within one hour and lasts for three to four hours (Baker, 1972).
The equivalent of one or two cups of coffee (150 to 250 mg of caffeine) is sufficient to induce adverse effects. The occurrence of hyperesthesia, an unpleasant sensory sensation, can be stimulated by large doses of caffeine.
Stimulation of the CNS is followed by depression (Klein and Salzman, 1975), although the effect is small at low doses e.g. a single cup of coffee. After two hours, Klein reported that males (but not females) showed a lower CNS stimulation compared to placebo. The post stimulation "let down" with caffeine results in fatigue and lethargy and the constant stimulation caused by chronic caffeine dosing could be disastrous (Abrams, 1977; Dowell, 1965).
Caffeine is known to interact with other drugs resulting in a modified effect. For example, caffeine administered with nardil (an MAO inhibitor) caused headaches and high blood pressure (Pakes, 1979). This potentially dangerous interaction was first noted by Berkowitz et al., (1971) and implicated serotonin in the mechanism.
Behavioral Effects: Caffeine's stimulating activity on the central nervous system as well as other body organs results in certain physiological effects which may be considered to be behavior oriented. Caffeine produces more rapid, clearer flow of thought, allays drowsiness and fatigue, increases the capability of a greater sustained intellectual effort and more perfect association of ideas. It also causes a keener appreciation of sensory stimuli, and reaction time is diminished. Motor activity is increased; typists, for example, work faster with fewer errors. Tasks requiring delicate muscular cobrdination and accurate timing may, however, be adversely affected. All of this occurs at doses of 150 to 250 mg of caffeine (approximately two cups of coffee) according to Ritchie (1975).
In 1912, Hollingsworth who was a psychologist reported caffeine's effect on mental and ~notor efficiency in a study sponsored by Coca-Cola. In nine double-blind tests, he found beneficial effects for both mental and motor performance at doses of 65 to 130 mg of caffeine. At a dose of 300 mg, caffeine caused tremors, poor motor performance and insomnia. These results have withstood the test of time (Stephenson, 1977).