I'll argue this legitimately since most of you seem to be grossly misinformed.
1. There are hardly any negative effects that are notable enough to bar medicinal use (it is also a dependance-forming substance, believe it or not).:
The effects of cannabis and THC
by
Grotenhermen F
nova-Institut,
Hurth, Germany.
FGrotenhermen@compuserve.com
Forsch Komplementarmed 1999 Oct; 6 Suppl 3:7-11
ABSTRACT
Cannabis and THC exert manifold actions on a number of organ systems. A lethal dose of THC in humans is unknown. Above the psychotropic threshold, ingestion of cannabis causes an enhanced well-being and relaxation with an intensification of ordinary sensory experiences. The most important unwanted acute psychical effects are anxiety and panic attacks. Acute somatic effects are increased heart rate, changes of blood pressure, conjunctival injection and dry mouth. Properties that might be used therapeutically comprise analgesia, muscle relaxation, sedation, increase of mood, stimulation of appetite, antiemesis, lowering of intraoccular pressure and bronchodilation.
Chronic use may lead to dependency and to a mild withdrawal syndrome.
The extent of possible long-term damage on psyche and cognition, immune system, fertility and pregnancy remains controversial. Marijuana can induce a schizophrenic psychosis in vulnerable persons presumably without increasing the incidence of the disease. Disturbance of immunological and hormonal functions and long-term impairment of memory, attention, and complex cognitive processes are low and do not preclude a legitimate therapeutic use.
2. There are no long-term cognitive effects that aren't reversable by abstinence:
Cognitive measures in long-term cannabis users
by
Harrison GP Jr, Gruber AJ, Hudson JI,
Huestis MA, Yurgelun-Todd D.
Biological Psychiatry Laboratory,
McLean Hospital/Harvard Medical School,
Belmont, Massachusetts 02478, USA.
J Clin Pharmacol 2002 Nov;42(11 Suppl):41S-47S
ABSTRACT
The cognitive effects of long-term cannabis use are insufficiently understood. Most studies concur that cognitive deficits persist at least several days after stopping heavy cannabis use. But studies differ on whether such deficits persist long term or whether they are correlated with increasing duration of lifetime cannabis use. The authors administered neuropsychological tests to 77 current heavy cannabis users who had smoked cannabis at least 5000 times in their lives, and to 87 control subjects who had smoked no more than 50 times in their lives. The heavy smokers showed deficits on memory of word lists on Days 0, 1, and 7 of a supervised abstinence period. By Day 28, however, few significant differences were found between users and controls on the test measures, and there were few significant associations between total lifetime cannabis consumption and test performance. Although these findings may be affected by residual confounding, as in all retrospective studies, they suggest that cannabis-associated cognitive deficits are reversible and related to recent cannabis exposure rather than irreversible and related to cumulative lifetime use.
3. More clarification on cannabis and schizophrenia.
Cannabis, vulnerability, and the onset of
schizophrenia: an epidemiological perspective
by
Hambrecht M, Hafner H
Department of Psychiatry and Psychotherapy,
University of Cologne, Germany.
martin.hambrecht@medizin.uni-koeln.de
Aust N Z J Psychiatry 2000 Jun; 34(3):468-75
ABSTRACT
OBJECTIVE: Second to alcohol, cannabis is the most frequently misused substance among patients with schizophrenia. The aim of this paper is to examine at early onset of psychosis whether the high comorbidity of schizophrenia and cannabis abuse is due to a causal relationship between the two disorders. Previous studies have mostly included chronic patients or samples with mixed stages of the psychotic illness.
METHOD: In a German catchment area with a population of 1,500,000, a representative first-episode sample of 232 patients with schizophrenia was included in the Age, Beginning and Course of Schizophrenia Study. By means of a structured interview, the Retrospective Assessment of the Onset of Schizophrenia, the onset and course of schizophrenic symptoms and of substance abuse was systematically assessed retrospectively. Information given by relatives validated the patients' reports.
RESULTS: Thirteen per cent of the sample had a history of cannabis abuse, which was twice the rate of matched normal controls. Male sex and early symptom onset were major risk factors. While cannabis abuse almost always preceded the first positive symptoms of schizophrenia, the comparison of the onset of cannabis abuse and of the first (prodromal) symptoms of schizophrenia differentiated three approximately equal groups of patients: group 1 had been abusing cannabis for several years before the first signs of schizophrenia emerged, group 2 experienced the onset of both disorders within the same month, and group 3 had started to abuse cannabis after the onset of symptoms of schizophrenia.
CONCLUSIONS: The vulnerability-stress-coping model of schizophrenia suggests possible interpretations of these findings. Group 1 might suffer from the chronic deteriorating influence of cannabis reducing the vulnerability threshold and/or coping resources.
Group 2 consists of individuals which are already vulnerable to schizophrenia. Cannabis misuse then is the (dopaminergic) stress factor precipitating the onset of psychosis. Group 3 uses cannabis for self-medication against (or for coping with) symptoms of schizophrenia, particularly negative and depressive symptoms. These patients probably learn to counterbalance a hypodopaminergic prefrontal state by the dopaminergic effects of cannabis. The implications of these very preliminary results include issues of treatment and prognosis, but replication studies are needed
4. Here's a pretty straight-forward analysis of the war on drugs:
"Just say know"
to teenagers and marijuana
by
Rosenbaum M
The Lindesmith Center,
San Francisco,
California 94123, USA.
J Psychoactive Drugs 1998 Apr-Jun; 30(2):197-203
ABSTRACT
Despite increasing expenditures on prevention, government survey after survey indicates that marijuana use--which comprises 90% of illicit drug use--has not been eradicated among teenagers. Today's adolescents have been exposed to the largest dose of prevention in our history. After three decades of such efforts, one must ask why young people continue to use marijuana, and why drug education has failed to bring about a marijuana-free teenage America. Drug education falls short because it is based on a "no-use" premise, scare tactics and top-down teaching. Such programs do not educate, and may even be counterproductive for those who choose to say "maybe" or "sometimes," or "yes." Moreover, drug education, as has been the case since its advent, is based on politics rather than science--an enormous taxpayer drain with few demonstrative results. A new strategy for drug education requires a pragmatic view that accepts the ability of teenagers, if educated honestly and in ways they trust, to make wise decisions leading, if not to abstinence, to moderate, controlled, and safe use.