consumption of the food is reduced, it is wise to include a pair-fed control group to determine 
whether results are attributable to the drug or to the reduced caloric or fluid intake. 
HEALTH CONSIDERATIONS 
Behavioral pharmacology experiments generally are designed to avoid irreversible effects or 
potential loss of the animal. Some behavioral toxicology experiments, however, will involve 
dosing that produces cumulative deleterious effects. A contingency plan that addresses the 
conditions under which side effects are to be alleviated or the animal is to be removed from 
the experiment should be planned for in the protocol. 
DRUG SIDE EFFECT 
Some drugs studied in behavioral pharmacology, particularly when dosing is frequent, will 
affect feeding and drinking, activity level, and other bodily functions (e.g., elimination). 
Nevertheless it can be too easy to assume that alterations in such processes are an effect of 
the drug and thus to overlook other causes of behavioral changes during a drug study (e.g., 
dental problems that affect food consumption). 
PHYSICAL DEPENDENCE 
Although mere repeated administration of a drug will not necessarily produce physical 
dependence on a drug, physical dependence can sometimes occur as a consequence of 
repeated dosing procedures (Goldberg and Stolerman, 1986). A characteristic withdrawal 
syndrome upon cessation of the chronic dosing regimen reveals physical dependence. The 
features of the withdrawal syndrome and the rapidity with which it appears after the drug has 
been stopped are idiosyncratic to the nature of the drug that has been chronically delivered 
(e.g., the opioid withdrawal syndrome differs from the barbiturate withdrawal syndrome). The 
severity of the withdrawal syndrome typically is an interactive function of the daily dose and 
duration of the period of chronic drug delivery. In addition, individual animals, particularly 
from outbred strains, will differ somewhat in the particular signs and symptoms they exhibit 
in withdrawal and in the apparent degree of severity. Some experiments involve deliberately 
administering a compound under a particular regimen in order to study physical dependence 
to the drug; however, where the dosing regimen is one in which it is known that a withdrawal 
syndrome could occur, it is reasonable to anticipate the possibility and suggest steps that 
could be taken to diminish discomfort in the protocol. 
Whether or not there is treatment of a withdrawal syndrome in the laboratory depends on the 
purpose of the experiment and the nature of the withdrawal. If the purpose is to study the 
nature of the withdrawal syndrome, including whether or not there will be such a syndrome 
(e.g., for newly developed compounds), then providing pharmacological treatment to 
ameliorate it may be antithetical to the purposes of the experiment. It is always desirable, 
though, to have a "contingency plan" for treatment if a life-threatening sign occurs (e.g., 
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