Schizophrenia addictive drugs

In previous chapters, we examined drugs specifically intended to keep you awake (such as caffeine) and drugs that are specifically intended to help you sleep (such as benzodiazepines). There are, however, many medications that are taken for the purpose of treating other medical conditions—allergies, high blood pressure, epilepsy, obesity, chronic pain, and psychiatric disorders such as schizophrenia and depression—that also can affect your sleep. In addition, addictive drugs such as alcohol, nicotine, and cocaine have strong effects on sleep. 

Dopamine autoreceptors play a role in Parkinson s disease, schizophrenia and drug addiction. Dopamine heteroreceptors affecting the release of acetylcholine and of amino acid neurotransmitters in the basal ganglia are also relevant for Parkinson s disease. Peripheral dopamine heteroreceptors on postganglionic sympathetic terminals influence heart rate and vascular resistance through modulation of noradrenaline release. 

The role that dopamine plays in regulating mood and emotional stability can be at least partially grasped by examining dopamine s role in schizophrenia and drug addiction. Schizophrenia is a disorder characterized by delusions, hallucinations, withdrawal from external reality, and emotional unresponsiveness. The dopamine theory of schizophrenia, proposed in 1965, attributes the disorder to elevated brain concentrations of dopamine or to a hypersensitivity of dopaminergic receptors, especially the D2 and D4 receptor subtypes. Several drugs used to treat schizophrenic patients bind to D2 and D4 receptors and block the dopaminergic response. 

Drug abuse and dependence Prolonged abuse of ephedrine can lead to symptoms of paranoid schizophrenia. Patients exhibit such signs as tachycardia, poor nutrition and hygiene, fever, cold sweat, and dilated pupils. Some measure of tolerance develops, but addiction does not occur. 

Payte TJ (2003). Methadone treatment. Safe induction techniques. Heroin Addiction Related Clinical Problems, 6, 35-42 Pearson G (1996). Drugs and deprivation. Journal of the Royal Society of Health, April, 113-6 Penk WE, Flannery RB Jr, Irvin E, Geller J, Fisher W Hanson MA (2000). Characteristics of substance-abusing persons with schizophrenia the paradox of the dually diagnosed. Journal of Addictive Diseases, 19, 23-30... 

Attention has been focused on dopamine because of its relationship to neurological diseases and to addiction (discussed in Section 10). Dopamine receptors constitute a large family, which are classified into two main subfamilies. The D, subfamily consists of D1a and D1B (D5) receptors and the D2 subfamily of D2, D3, and D4 receptors.763 764 The D, receptors, which are prominent in the prefrontal cortex and also in the striatum, are more abundant than the D2 receptors, which are also present in the striatum and the pituitary and are targets for antipsychotic drugs such as haloperidol (Fig. 30-33).765 The recently discovered and less numerous D3 receptors are present in only a few regions of the brain. However, a deficiency of D3 receptors may also be involved in addiction, schizophrenia, and Parkinson disease.766 767... 

Because VMAT regulates the level of cytosolic monoamines, researchers have examined a role for VMAT in disease states. Although no direct pathological links to aberrant VMAT function have been described, altered dopamine regulation can lead to drug addiction, Parkinson s disease, and schizophrenia (Mazei-Robison et al.,... 

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