DRUGS• A DRUG can be defined as a natural or syntheticsubstance that is used to produce physiologicalor psychological effects in humans or otherhigher-order animals.• The word “drugs” means something different toeach person.– Drugs can be necessary for sustaining or prolonginglife– Drugs can provide an escape from the pressures oflife– Drugs can be used as a means to end ones life
DRUGS• During the 1960’s, successive waves ofhallucinogens, amphetamines and barbituratesfound their way out of laboratories, pharmaciesand medicine chests and into the streets.During this decade, marijuana became the mostwidely used illicit drug in the United States, andalcohol consumption continued to rise – today90 million Americans drink alcohol regularly, and10 million of these are hopelessly addicted orhave severe problems in coping with theirdrinking habits.
DRUGS• Approximately 23 million people in the United Statesuse illicit drugs, including about a half million heroinaddicts and nearly six million users of cocaine.• In the United States, more than 75% of the evidenceevaluated in crime laboratories is drug related.– Guns– Drugs– Documents– Evidence from Drug related Homicides or Agg. Assaults
Drug Dependence• Before we talk about Drug Dependence, letsreview the neurophysiological effect of drugs.In order to do that, we must first study theanatomy and physiology of the humannervous system.
Anatomy and PhysiologyThe Nervous System• The nervous system operates very much like acomputer system. Information is entered intothe computer by various “senses”: the keyboard,mouse, microphone, Internet connection, and soon. The main components of the computer’s“brain” are the hard drive (long term memory),and the central processing unit (thinking anddecision making). The computer’s output – itsinteraction with the world – exits via ports andcables to printers, displays, speakers, and otherdevices.
Anatomy and PhysiologyThe Nervous System• The Nervous System is divided into two mainparts: The Central Nervous System (CNS)which is composed of the brain and spinalcolumn, and the Peripheral Nervous System(PNS) which is composed of the input andoutput pathways of the nervous system;essentially the nerves outside of the brainand spinal cord.
The Nervous SystemNervous SystemCentral NervousSystem(CNS)Brain and Spinal CordPeripheral Nervous System(PNS)Nerves outside of Brainand Spinal CordSomatic or Voluntary(skeletal muscles)Autonomic(smooth and cardiacmuscles and glands)Parasympathetic Branch(homeostasis and dailymaintenance)Sympathetic Branch(alert system)
Parts and Basic Operation of theNervous System• Central Nervous System: Brain and Spinal Cord:Controls all basic bodily functions and responds toexternal changes.• Peripheral Nervous System: All nerves outside of theCentral Nervous System: Provides a completenetwork of motor and sensory fibers connecting thecentral nervous system to the rest of the body.• Autonomic Nervous System: Parasympathetic andsympathetic nervous system: Parallels the spinal cordbut is separately involved in control of exocrineglands, blood vessels, viscera, and external genitalia.
Parts and Basic Operation of theNervous System• The nervous system’s “input devices” comprisethe sensory system. Your senses sample theenvironment and bring the information to thenervous system. Your sensory system absorbsand measures information about everything andanything, both within your body and the outsideenvironment. This sensory information then goesinto the nervous system, where it is handled bythe brain and spinal cord. The brain and spinalcord combine the input with other kids ofinformation, compare it to information from pastexperiences, and make decisions about how torespond to the information.
Parts and Basic Operation of theNervous System• Once the brain and spinal corddetermine an appropriateresponse to manage the newinformation, the output side isactivated. The output sidecarries out the orders fromthe brain and spinal cord. Theoutput side, often called themotor system, carries ordersto all three types of musclesand to the body’s glands,telling them how to respondto the new information.
The Motor System• The motor system is divided intotwo branches: the somaticnervous system, which controlsskeletal muscle and voluntarymovements, and the autonomicnervous system, which controlssmooth and cardiac muscle inyour organs and also severalglands. Autonomic output isinvoluntary and not underconscious control.• The autonomic nervous systemis further divided into twobranches: The parasympatheticand sympathetic.
The Autonomic Nervous System• The Parasympathetic branch, often called“resting and digesting”, deals with normalbody functioning.• The Sympathetic branch, is the body’s alertsystem, commonly known as the “fight-or-flight” response system.
Nervous Tissue• Like all organs, the components of thenervous system are made up of tissue.• (This section is for the nursing students) Butunlike other systems, the nervous systemcontains no epithelium, connective tissue, ormuscle tissue. Nervous tissue is made up oftwo different types of cells:– Neuroglia– Neurons
Neuroglia• The neuroglia or glial cellsare specialized cells innervous tissue that allowit to perform nervoussystem functions. In theCNS, there are four typesof glial cells:• ASTROCYTES• MICROGLIA• EPENDYMAL CELLS• OLIGODENDROCYTES
Neuroglia (CNS)• Astrocytes: are metabolic and structuralsupport cells that hold the neurons and bloodvessels close together.• Microglia: can attack microbes and removedebris.• Ependymal cells: do the job of epithelialcells, covering surfaces and lining cavities.• Oligodendrocytes: hold nerve fibers togetherand make a lipid insulation called myelin.
Neuroglia (PNS)• In the peripheral nervous system, there are onlytwo types of glial cells: Schwann Cells, whichmake myelin for the PNS, and satellite cells, whichare support cells.
Neurons• The glial cells do all the support activities forthe nervous system, such as lining andcovering cavities and supporting andprotecting structures. None of the glial cells,however, are capable of measuring theenvironment, making decisions, or sendingorders. All of the control functions of thenervous system must be carried out by asecond group of cells called neurons.
Neurons• Neurons are rather bizarre-looking cells, often withmany branches and what appears to be a tail. Themain function of a neuron is to transmit messagesfrom one cell to another, throughout the body. Eachpart of a neuron has a specific function.• The neuron cell body’s main function is that of cellmetabolism.• It’s dendrites receive information from theenvironment or from other cells that carry thatinformation to the cell body.• The axon generates and sends signals to other cells.Those signals travel down the axon until they reachthe axon terminal, which then connects to a receivingcell. This space between the axon terminal andreceiving cell is called a synapse. If the receiving cellis a skeletal muscle, the this particular synapse iscalled the neuromuscular synapse or junction.
Brain Anatomy and Physiology• The Brain is divided into three main sections:The CerebrumThe CerebellumBrain Stem• The Cerebrum is the largest part of the brain,and is divided into two hemispheres, the rightand left, and is divided by the longitudinalfissure. It is divided from the cerebellum(little brain) by the transverse fissure.
Brain Anatomy and Physiology• The brain is further dividedinto four lobes, much like themajor departments in agrocery store are separated byaisles.• The lobes are named for theskull bones that cover them,and they occur in pairs, one ineach hemisphere. The mostanterior lobes, are the frontallobes.• Posterior to the frontal lobesare the parietal lobes.• Posterior to the parietal lobesare the occipital lobes.• The most inferior lobes are thetemporal lobes.
Cerebral Hemispheres• There is a section of the brain,the insula, deep inside thetemporal lobes, which is oftenlisted as the fifth lobe, but itis not visible on the surface ofthe cerebrum.• Much of the informationcoming from your brain iscontralateral, meaning thatthe left side of the body iscontrolled by the right side ofyour cerebrum, and the rightside of the body is controlledby your left brain.
Cerebellum• The cerebellum is posteriorto the brain stem and playsan important role insensory and motorcoordination and balance.Its surface is alsoconvoluted like that of thecerebrum. From itsexternal appearance, it iseasy to see why anatomistsconsider the cerebellumthe “little brain”.
• In assessing the potential danger of drugs, societyhas become particularly conscious of their effectson human behavior. In fact, the first drugs to beregulated by law in the early years of thetwentieth century were those deemed to have“habit-forming” properties. The early laws wereaimed primarily at controlling opium and itsderivatives, cocaine, and later, marijuana. Theability of a drug to induce dependence afterrepeated use is submerged in a complex array ofphysiological and social factors.
• Dependence on drugs exists in numerous patterns andin all degrees of intensity, depending on the nature ofthe drug, the route of administration, the dose, thefrequency of administration, and the individual’s rateof metabolism. Furthermore, nondrug factors play anequally crucial role in determining the behavioralpatterns associated with drug use. The personalcharacteristics of the user, his or her expectationsabout the drug experience, society’s attitudes andpossible responses, and the setting in which the drug isused are all major determinants of drug dependence.
• The question of how to define and measure adrug’s influence on the individual and itsdanger to society is difficult to assess. Thenature and significance of drug dependencemust be considered from two overlappingpoints of view:– The interaction of the drug with the individual– The drugs impact on society
• The common denominator that characterizesall types of repeated drug use is the creationof a psychological dependence for continueduse of the drug.• Not all drug users are hopeless “addicts”• Most users present quite a normalappearance and remain both socially andeconomically integrated in the life of thecommunity
• The reasons why some people abstain from drugswhile others become moderately of heavily involvedare difficult if not impossible to delineate. Whateverthe reasons, the underlying psychological needs andthe desire to fulfill them create a conditioned patternof drug abuse.– Desire to create a sense of Well Being– Escape from Reality• Personal Problems• Stressful situations– Sustaining a physical and emotional state of increased orenhanced performance
• The intensity of the psychological dependenceassociated with a drug’s use is difficult todefine and largely depends on the nature ofthe drug used. For drugs such as alcohol,heroin, amphetamines, barbiturates, andcocaine, continued use will likely result in ahigh degree of involvement. Other drugs,such as marijuana and codeine, appear tohave a considerably lower potential for thedevelopment of psychological dependence.
• Our general knowledge of alcoholconsumption should warn us ofthe fallacy of generalizing whenattempting to describe thedanger of drug abuse. Obviously,not all alcohol drinkers arepsychologically addicted to thedrug; most are “social” drinkerswho drink in reasonable amountsand on an irregular basis. Manypeople have progressed beyondthis stage and consider alcohol anecessary crutch for dealing withlife’s stresses and anxieties.
• Alcohol abusers exhibit a wide range ofbehavioral patterns, and to a large extent thedetermination of the degree of psychologicaldependence must be made individually.Likewise, it would be wrong to generalize that allusers of marijuana can at worst develop a lowdegree of dependence on the drug. A widerange of factors also influence marijuanaseffect, and heavy users of the drug exposethemselves to the danger of developing a highdegree of psychological dependence.
• Although emotional well-being is the primarymotive leading to repeated and intensivedrug use, certain drugs, taken in sufficientdoes and frequency, can producephysiological changes that encourage theircontinued use. Once the user abstains fromsuch a drug, sever physical illness follows.The desire to avoid this withdrawal sickness,or abstinence syndrome, ultimately causesphysical dependence , or addiction.
• Examples of Symptomsrelated to AbstinenceSyndrome associatedwith Heroin:– Body Chills– Vomiting– Stomach Cramps– Convulsions– Insomnia– Pain– Hallucinations
• Some other of the more widely abused drugshave little or no potential for creating physicaldependence. Drugs such as marijuana, LSD, andcocaine create strong anxieties when theirrepeated use is discontinued; however, nomedical evidence attributes these discomforts tophysiological reactions that accompanywithdrawal sickness. On the other hand, use ofalcohol, heroin, and barbiturates can result indevelopment of physical dependence.
• Delirium Tremens is a severe form of alcohol withdrawalthat involves sudden and severe mental or nervoussystem changes.– Body Tremors– Changes in mental function• Agitation• Confusion• Deep sleep that lasts for a day or longer• Delirium• Hallucinations• Sensitivity to light , sound, touch• Stupor, sleepiness, fatigue• Quick mood changes• Decreased attention span– Seizures (generalized tonic-clonic seizures)– Symptoms of Alcohol Withdrawal