CLINICAL HANDBOOK OF SCHIZOPHRENIA

Time-Line Follow-BackThe Time-Line Follow-Back (TLFB) utilizes a calendar and tools to aid patient recall ofsubstance use over varying lengths of time. Studies have found the TLFB useful in detectedunderreported use of alcohol.Breathalyzer13. Co-Occurring Disorders 127Alcohol use can be measured within 40–70 minutes after consumption of any alcoholicdrink. The amount of alcohol in the blood reaches its highest level about an hour afterdrinking. The rest of it is passed out of the body in urine and exhaled breath. ABreathalyzer can measure blood alcohol concentration (BAC) from a puff of air. Accordingto the American Medical Association, impairment can occur at levels of 0.05; however,most states report legal limits of 0.08. Breathalyzer results cannot be used to indicatelevels of use over time. The reading only provides for clinicians a current BAClevel.Toxicology Screening (Urine and Blood)A toxicology test can be used to monitor specific drug use. A wide variety of substances,including cocaine, marijuana, alcohol, and amphetiamines, may be monitored. Thoughtests of urine and blood are available, urine tests are easier to do, and a wider number ofdrugs can be detected in the urine. Also, a drug (or its metabolized form) may be detectablefor a longer period of time in urine than in blood. Clinicians should have access to alist of current medications (prescription and nonprescription), herbal supplements, vitamins,and other substances that the patient has taken in the prior 4 days, because theymay interfere with testing. Most toxicology tests determine only the presence of drugs inthe body, not the specific level or quantity. Follow-up testing is often required to determinethe exact level of a certain drug in the body and confirm the results of the initialtest. Results that indicate drug use or abuse should be confirmed by at least two differenttest methods because of the possibility of false-positive results. For suspected drug abuse,a trained person may need to witness the urine or blood collection.Hair AnalysisAlthough hair analysis is being done more frequently to test for illegal drug use (e.g., cocaineor marijuana use), it is not always widely available. Hair samples are taken from aspecific part of the body, such as from the back of the scalp by the neck or from the pubicarea. Hair close to the skin or scalp includes the most recent growth, which provides themost accurate information about recent use. Hair samples do not indicate recent changesin the body, such as drug use within the past few days, or the amount of substance thatwas used.NICOTINE DEPENDENCEPersons with schizophrenia are more likely to be smokers than are people in the generalpopulation. Approximately 70–90% of people with schizophrenia smoke compared toabout 25% of the general population. People with schizophrenia are more likely to bedaily smokers compared to people in the general population. Daily smoking is usuallyconsidered a sign of nicotine addiction. Smoking in this population is associated with the