[The effects of cannabis and THC]

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.