Superb insights excerpted from pp 170-172 of Psychotic depression by Conrad M Swartz and Edward Shorter. Cambridge University Press, 2007. Words in square brackets were added by me, editorial cuts are indicated by ....
For the sake of discussion, we could say that one way to terminate all hallucinations, delusions, insomnia, and complaints of low mood and loss of interest [from someone with Psychotic Depression] would be to anaesthetize the patient to unconscousness...
Yet this would be symptom management, not treatment, scarcely a desirable or sensitive form of practice.
More feasible than complete anaesthesia are drugs that only partly inhibit the brain from operating and superficially appear to leave the patient conscious. This is tranquilization.
Physiologically, benzodiazepine and barbiturate tranquilizers [and one could add alcohol] are called 'depressants' because they diminish brain functions.
In low to moderate doses they inhibit learning, recall, coordination, awareness of complexity, problem solving, willpower and attention.
In larger doses they are general anaesthetics and can cause unconsciousness...
Antispychotic [or neuroleptic] tranquilizers inhibit the functioning of only some areas of the brain: those related to new thoughts, novel problem solving, social complexity, initiative and motivation.
These functions are housed in the prefrontal section of the brain. This sounds like a small fraction of the brain, but in humans the prefrontal region is almost half the brain cortex.
Its functions represent the essential differences in psychological performance between humans and animals, and also between human adults and children...
The deficits in psychological performance caused by antipsychotic drugs mentioned here occur similarly in patients with Parkinson's disease...
Both with antipsychotic drugs and Parkinson's disease, the function of dopaminergic brain cells is deficient...
Both groups... show impairments in problem-solving abilities, planning, initiative taking, and dealing with complexity...
The behavioural results... vary with the particular antipsychotic drug.
Dopamine-blocking antipsychotic drugs - such as haloperidol, perphenazine, and risperidone- decrease motivation to speak, together with lessening complexity and amount of thought.
Some of the more recently introduced antipsychotics (e.g. olanzapine, clozapine, and quetiapine) decrease thought complexity more than motivation to speak; and because the patient speaks abundantly the thought simplicity is easier to notice.
Decreases in self-discipline and organization contribute to the weight gain patients experience from olanzapine, clozapine, and quetiapine.
Olanzapine and clozapine also obstruct the function of the medial prefrontal cortex, which causes apathy, somnolence, and generalized weakness.
Anaesthetizing brain function is surely a last resort.
It is management, not treatment.