mental health disorders
Antipsychotic Drugs
How Antipsychotic Drugs Work
Antipsychotic drugs work by influencing how information is transmitted between individual brain cells. The adult brain is made up of more than 10 billion nerve cells called neurons. Each neuron in the brain has a single long fiber called an axon, which transmits information to other neurons (see figure Typical Structure of a Nerve Cell ). Like wires connected in a vast telephone switchboard, each neuron makes contact with several thousand other neurons. Information travels down a cell’s axon as an electrical impulse. When the impulse reaches the end of the axon, a tiny amount of a chemical called a neurotransmitter is released to pass information on to the next cell down the line. A receptor on the receiving cell detects the neurotransmitter, which causes the receiving cell to generate a new impulse. Symptoms of psychosis appear to be caused by excessive activity of cells sensitive to the neurotransmitterdopamine. Therefore, antipsychotic drugs work by blocking receptors so that communication between groups of cells is reduced. How well different antipsychotic drugs block different types of neurotransmitters varies. Every effective antipsychotic drug known blocksdopaminereceptors. The newer antipsychotic drugs (asenapine,clozapine,iloperidone,lurasidone,olanzapine,quetiapine,risperidone, andziprasidone) also block receptors for serotonin, another neurotransmitter. Experts thought that this property might make these drugs more effective. However, recent studies have not supported this view. Clozapine, which also blocks many other receptors, is clearly the most effective drug for psychotic symptoms. But it is not commonly used because of its serious side effects and the need for monitoring with blood tests. 