antidepressants and hallucinations

   The term antidepressant was introduced in or shortly before 1953 by the American psychiatrists Harry M. Salzer (b. 1906) and Max L. Lurie (b. 1920) in a barely noticed article on the mood-altering potential of the tuberculo-static isoniazid. As the French psychiatrists Jean Delay (1907-1987) and Jean-François Buisson had noted a year before Salzer and Lurie, iso-niazid appeared to be well suited to treat anxiety and depressive symptoms. Today the term antidepressant is used in a broad as well as a more restricted sense. In the restricted sense, it denotes a group of psychotropic substances with varying chemical structures which are used in the treatment of an array of psychiatric and neurological symptoms and disorders, including depression, depressive disorder, dysthymia, bipolar disorder, obsessive-compulsive disorder, anxiety, anxiety disorders, eating disorders, chronic pain, and " hyperaesthesia. In a broader sense, the term antidepressant has been used to designate other compounds and methods with the potential to alleviate a clinically depressed mood, some of which have been used since ancient times. In this broad sense, antidepressants include various nutrients, various herbal and plant preparations (notably opium, phencyclidine, and Saint John's wort), electric convulsive therapy (ECT), light therapy (LT), transcranial magnetic stimulation (TMS), acupuncture, "sleep deprivation, and psychotherapy. The exact mechanism of action of antidepressant substances is unknown.

   Although traditionally a major part of their action is attributed to their influence upon the serotonergic system of the CNS, they are also known to affect dopaminergic, cholinergic, and other neurotransmitter systems. Antidepressant substances are notorious for their many possible adverse effects, including the induction of delusions, " illusions, and hallucinations. Among the hallucinatory phenomena reported by individuals using antidepressant substances are " hypnagogic and "hypnopompic hallucinations, "simple and "complex visual hallucinations, and "verbal and " nonverbal auditory hallucinations (including " musical hallucinations). The neurophysiologi-cal correlates of these hallucinations are likewise unknown. Some hypotheses focus on the direct action of antidepressants upon the perceptual system via the serotonergic and cholinergic systems. Others focus on their indirect effects due to the release of serotonin-mediated dopamine (suggesting an analogy with the purported mechanism underlying hallucinations in the major psychotic disorders), the suppression of REM sleep (suggesting an involvement of the brain's sleep-dream system), and blurred vision (suggesting a mechanism similar to that underlying the " Charles Bonnet syndrome).

   References

   Salzer, H.M., Lurie, M.L. (1953). Anxiety and depressive states treated with isonicotinyl hydrazide (isoniazid). Ohio State Medical Journal, 51, 437-441.

   Cancelli, I., Marcon, G., Balestrieri, M. (2004).

   Factors associated with complex visual hallucinations during antidepressant treatment. Human Psychopharmacology: Clinical and Experimental, 19, 577-584.