Substance Abuse and Dependence Health Article

Causes & symptoms

It is generally believed that there is not one single cause of substance abuse, though scientists are increasingly convinced that certain people possess a genetic predisposition that can affect the development of addictive behaviors. One theory holds that a particular nerve pathway in the brain (dubbed the "mesolimbic reward pathway") holds certain chemical characteristics that may increase the likelihood that substance use will ultimately lead to substance addiction. Certainly, however, other social factors are involved, including family problems and peer pressure. Primary mood disorders (bipolar), personality disorders, and learned behaviors can be influential on the likelihood that a person will become substance dependent.

The symptoms of substance abuse may be related to its social as well as its physical effects. The social effects of substance abuse may include dropping out of school or losing a series of jobs, engaging in fighting and violence in relationships, and legal problems (ranging from driving under the influence to the commission of crimes designed to obtain the money needed to support an expensive drug habit).

Physical effects of substance abuse are related to the specific drug being abused:

• Opioid drug users may appear slowed in their physical movements and speech, may lose weight, exhibit mood swings, and have constricted (small) pupils.
• Benzodiazapine and barbiturate users may appear sleepy and slowed, with slurred speech, small pupils, and occasional confusion.
• Amphetamine users may have excessively high energy, inability to sleep, weight loss, rapid pulse, elevated blood pressure, occasional psychotic behavior, and dilated (enlarged) pupils.

• Marijuana users may be sluggish and slow to react, exhibiting mood swings and red eyes with dilated pupils.
• Cocaine users may have wide variations in their energy level, severe mood disturbances, psychosis, paranoia, and a constantly runny nose. Crack cocaine use may cause aggressive or violent behavior.
• Hallucinogenic drug users may display bizarre behavior due to hallucinations (hallucinations are imagined sights, voices, sounds, or smells which seem completely real to the individual experiencing them) and dilated pupils. LSD can cause flashbacks.

Other symptoms of substance abuse may be related to the form in which the substance is used. For example, heroin, certain other opioid drugs, and certain forms of cocaine may be injected using a needle and a hypodermic syringe. A person abusing an injectable substance may have "track marks" (outwardly visible signs of the site of an injection, with possible redness and swelling of the vein in which the substance was injected). Furthermore, poor judgment brought on by substance use can result in the injections being made under dirty conditions. These unsanitary conditions and the use of shared needles can cause infections of the injection sites, major infections of the heart, as well as infection with HIV (the virus which causes AIDS), certain forms of hepatitis (a liver infection), and tuberculosis.

Cocaine is often taken as a powdery substance that is "snorted" through the nose. This method of use can result in frequent nosebleeds, sores in the nose, and even erosion (an eating away) of the nasal septum (the structure that separates the two nostrils). Other forms of cocaine include smokable or injectable forms such as freebase and crack cocaine.

Overdosing on a substance is a frequent complication of substance abuse. Drug overdose can be purposeful (with suicide as a goal), or result from carelessness. It may also be the result of the unpredictable strength of substances purchased from street dealers, mixing of more than one type of substance or of a substance and alcohol, or as a result of the ever-increasing doses the person must take of those substances to which he or she has become tolerant. Substance overdose can be a life-threatening emergency, with the specific symptoms dependent on the type of substance used. Substances with depressive effects may dangerously slow the breathing and heart rate, lower the body temperature, and result in general unresponsiveness. Substances with stimulatory effects may dangerously increase the heart rate and blood pressure, increase body temperature, and cause bizarre behavior. With cocaine, there is a risk of stroke.

Still other symptoms may be caused by unknown substances mixed with street drugs in order to "stretch" a batch. A healthcare worker faced with a patient suffering extreme symptoms will have no idea what other substance that person may have unwittingly put into his or her body. Thorough drug screening can help with diagnosis.