Psychosis pathogenesis

The psychosis that least resembles dreaming is that of schizophrenia, because, like mania, it has the paranoia and accusatory auditory hallucinations (which dreaming lacks), and the emotional tone is often flat (about as far away from dream elation as we can get). Anxiety is about the only shared property, and that is not very specific. Perhaps it should come as no surprise that the typical schizophrenic psychosis is so different from that of dreaming. After all, it is the neuromodulator dopamine that has been most strongly implicated in the pathogenesis of schizophrenia, and that is the only neuromodulator that has not been implicated in dreaming. We will discuss this interesting difference in more detail when we consider how antipsychotic medication may work. 

The revival of interest in acetylcholine s role in schizophrenic pathogenesis is symmetrical to a new interest in dopamine s role in dream psychosis. Could it be that in both psychoses the coactivation of dopamine and acetylcholine systems is necessary but only sufficient if either the other aminergic systems are in abeyance (dream and depression psychosis) or the dopamine system overpowers the cholinergic system (manic and schizophrenic psychosis) ... 

LSD-25 to the behavioral and psychic actions of this drug. In other instances, we are still far from establishing such functional relations. It is hoped that renewed efforts with new and better techniques will enable us in the not-too-distant future to explain the whole "experience" produced by these substances, the whole "model psychosis," in terms of neural events. Should this be the case, one also would be a giant step closer to establishing a functional pathogenesis of endogenous mental disease i.e., one would be able to explain some or all the behavioral symptoms of the mentally ill in terms of abnormal neuronal function. It seems that with such a prospect in mind one could not think of a nobler task for a substance like LSD-25. 

Because of the prevalence of schizophrenia, this chapter concentrates on the treatment of this psychotic disorder. Also, the pathogenesis and subsequent treatment of other forms of psychosis are similar to... 

Consequently, antipsychotic drugs all share a basic mechanism of action that involves dopamine receptor blockade. It is apparent, however, that they are not all equal in their ability to affect specific sub-types of dopamine receptors, and that their effectiveness and side effects are related to their affinity and preference for certain receptors. As indicated earlier, other neurotransmitters may also be involved in the pathogenesis of psychosis, and differences in specific antipsychotic medications may be related to their ability to directly or indirectly affect these other transmitters as well as block dopamine influence. Future studies will continue to clarify how current antipsychotics exert their beneficial effects and how new agents can be developed to be more selective in their effects on dopamine and other neurotransmitter pathways. 

Pathogenesis of Psychosis in Epilepsy. The Seesaw Theory Myth or Reality ... 

In 1967 after 6 years of studies, trials of L-dopa in patients with Parkinson s disease showed dramatic improvements in aU motor deficits. The hypothesis that dopamine is involved in the pathogenesis of psychosis, in particular schizophrenia, rests on the finding that most antipsychotic drugs are dopamine-receptor antagonists and that agents which cause excessive release of dopamine mimic schizophrenia-like states. In 1979, John Kebabian and Donald Caine (NIH, Bethesda, USA) found that dopamine exerts its effects by binding to two subtypes of receptors. 

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