In a research titled the effects of cigarette smoking on verbal learning and retention written by G. L. Mangan of the Department of Experimental Psychology, University of Oxford, England investigated the effects of smoking in 24 subjects and their ability to learn and memorize, using low and high doses of nicotine packs.
INTRODUCTION: -
Previously studies in rats showed that nicotine can help learning and retention of certain tasks like bar pressing, shock avoidance, visual separation, etc. Nicotine also appears to help in getting things together in rats; however, this is dose dependent. It was seen that small doses help in alertness, whereas large doses of nicotine hamper the same.
These effects are however not very accurate as different methods and different doses of nicotine were used in various studies.
However, in humans, there is hardly any such study available to see the effects of nicotine but some scientists have noticed that smoking reduces learning ability, but subsequently increases recall of data.
In this particular study, effects of smoking were studied in retention of a verbal task given, and in another group the effects of learning. In the first group, different amounts of nicotine were given, while in the second group, various high and low tasks were given.
16 young males between 18 to 24 years were selected and evaluated after smoking both 1.3 mg cigarettes, and then 0.7 mg cigarettes each. Similarly, in the second group, 8 young men were similarly evaluated, as per trial parameters.
RESULTS: -
In the first group, using 1.3 mg nicotine, smoking caused more errors in telling out the facts, as compared to 0.7 mg dose, which did not have any significant effect.
In the other group, smoking 1.3 mg or 0.7 mg taken before trials, show significant increase in memory retention, irrespective of the degree of interference.
So, it appears that the supportive effect of smoking is only seen in long term memory recall, rather than short term memory
DISCUSSION: -
In paired associate learning, there was a small difference between nicotine level and task difficulty. Under certain conditions, 1.3 mg dose reduced learning, but when the given task was more difficult, the same dose surprisingly helped learning.
In retention of memory however, both dosage levels increased recall levels, especially in paired associate learning, irrespective of the given task.
In another study published in a reputed psychology journal by Henry Stevens of University of British Columbia indicated that tobacco smoking may have a deleterious effect on the learning process. One hundred and fifteen male volunteers were assessed on four learning tasks. Those who smoked in excess of 12 cigarettes per day did significantly less well, as a group, than non-smokers and light smokers on three of the four learning tests. This study continued the research into the smoker/nonsmoker dichotomy.
Its general aim was to investigate possible smoker-nonsmoker differences in the performance of complex learning tasks, with the specific hypothesis that there would be differences to the disadvantage of smokers. A further prediction was made that the extent of learning impairment would be associated with the amount of tobacco smoked. These hypotheses were based on the belief that certain outside agents such as those found in tobacco smoke have a basically disruptive effect on the nervous system and that this influence can be demonstrated behaviorally. The results are generally quite supportive of the central hypothesis that those who smoke do not perform as well on learning tests as do nonsmoking ones. Further- more, it appears that this disadvantage is related to degree of smoking rather than to smoking as such as the Light-Smoking group did as well as the nonsmoking group in this study. The effect of smoking on the learning process was detected only in the group of those who smoke in excess of 12 cigarettes per day. The author hesitates to conclude that smoking less than 13 cigarettes per day has no psychological consequences, but these results do suggest that this amount is measurably less harmful than smoking, for example, 20 cigarettes per day.
In another study by K. Anderson of the Psychology labs at University of Stockholm, Sweden, learning verbally and its effect was studied in ten habitual smokers both in smoking and non smoking sessions. Smoking actually reduced the number of correct replies as compared to non- smokers, raising the heart beat at the same time. However, 45 minutes after ending the verbal session; the increased arousal and heart rate level returned to normal, and also the memory retention was even better in the smokers group. This finding supports Walker's theory which also highlighted a link between arousal level and improvement of memory.
As early as 1972, a study showed that nicotine-containing cigarettes had a bad effect on learning, while those without nicotine had no such effects. This unwanted effect lasted for about 30 minutes after smoking, along with increased arousal level, as determined by heart beating rate.
A scientist suggested that increase in memory is followed by a temporary reduction on recall, serving to protect the trace memory against stoppage. He said that when a patient is aroused, high nerve transmission takes place, leading to significant improvement in long term memory.
In Humans, it was noticed that high arousal during learning was linked to poor immediate recall, which improved after a week; however, it was just the opposite in cases of low arousal levels. The aim of this study was to verify the earlier study of bad effect on learning, and whether there was a relation between arousal, learning and retention.
METHOD: -
Ten young males, ages from 20 to 25 years, having body weight about 58 to 70 Kgs were enlisted and were all habitual smokers. Each volunteer had to go through three sessions, namely: introductory session, a smoking session and a non- smoking session; each having a gap of 5 to 7 days in between. Heart rate was measured before and after session.
RESULTS: -
It was clear that smoking reduced learning ability as compared to non- smoking group; the maximum effect was seen in the initial treatment. On the other hand, better performance was seen in smokers after 45 minutes, when they were tested again for recall of data.
In smokers, the heart rate increased suddenly after smoking around 8 minutes into the study, which then gradually normalized, except for slight increase after the 45 minutes break. Heart rate in the non- smokers was almost the same
Hence this study consolidates Walkers theory that in smokers, reduction of learning new tasks could be related to increased arousal / heart rate, and this in turn leads to a better permanent memory of the task when it has been learned. These studies should discourage college students who smoke with the idea that they will learn better. After all it only seems to be a marketing gimmick of the cigarette companies.
Well, What about smokers who are not normal. How does smoking affect them ? Another study published in the American Journal on Addiction by Karolina Kozak, ,Darby J. E. Lowe , Tony P. George, MD FRCPC from Institute of Medical Sciences (IMS), University of Toronto , Addictions Division, Centre for Addiction and Mental Health (CAMH), Toronto , Department of Psychiatry, Division of Brain and Therapeutics, University of Toronto and Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Canada respectively, studied Incidence of smoking in schizophrenia (patients with mental disorder wherein one is troubled by unreal voices and visions that can command the untreated to commit grave acts which endanger lives) . The incidence of smoking in schizophrenics was found very high, almost 70 percent and difficulty in verbal learning and memory recall is associated with this disease. In fact smoking is temporarily known to improve defects in memory and learning process, but in an effort to improve the defects, do patients indulge in addiction to smoking ?
METHODS: -
In this study, the effects of Varenicline, a stimulator of nicotine, for memory and learning functions was tested on both smokers and non-smokers. 15 non smokers having schizophrenia, 15 non psychiatric - non smokers , 14 schizophrenic smokers and 14 non psychiatric - smokers were part of this study. The aim of this study was to see whether Varenicline would reduce memory and learning functions in smokers and non smokers with schizophrenia. During three separate weeks, patients were given dummy tablets known as placebo and then low dose Varenicline 1 mg /day and lastly high dose of Varenicline 2 mg/day for three days. Only figures from the dummy tablet was analyzed for this study. The patients were thoroughly screened before the start of this study.
RESULTS: -
After study reports showed that by having the three conditions of testing, there was a significant drop in verbal memory in schizophrenic smokers and non smokers. Also, there was a clear reduction of smoking in the schizophrenia smokers group. It was also discovered that smokers with schizophrenia had a rather bad effect on their memory and learning functions.
What came out clearly in this study was that reduction of smoking may selectively change verbal learning and memory in smokers with schizophrenia.
CONCLUSION: -
This study highlights the results for understanding the effects of smoking on functions such as verbal learning, and memory in smokers with schizophrenia. Because of high usage of tobacco in schizophrenic patients, gradual reduction of tobacco usage should be started to improve verbal learning and memory functions, which will further help in treating such patients.
Compiled from various international research journals available at google scholar by D. Mukherjee having 38 years of pharmaceutical (Cardiac, Diabetic, Neurology, Pain & Inflammation products) experience with a Swiss Multinational Company NOVARTIS and edited by Dr Sandeep Ahlawat, MBBS