Drug-seeking behaviour

Finally, there is little or no clinical evidence that morphine causes psychological dependence or drug-seeking behaviour, tolerance or problematic respiratory depression in patients. These events simply do not occur when opioids are used to control pain. The reason is likely to be that the actions of morphine and the context of its use in a person in pain are neurobiologically quite different from the effects of opioids in street use. These actions of opioids are described in more detail in Chapter 23. 

The difference in opiate pharmacology between people with and without pain also applies to addiction. The drug-seeking behaviour synonymous with drug addiction does not occur in patients given opiates for pain relief in childbirth, operations or heart attacks (Porter and Jick, 1980). Clearly, drug addicts are not in pain, and it has consequently been argued that medical use of opiates does not produce addicts (McQuay, 2001). 

Gerrits MA, Petromhli P, Westenberg HG, Di Chiara G, van Ree JM. 2002. Decrease in basal dopamine levels in the nucleus accumbens shell during daily drug-seeking behaviour in rats. Brain Res 924(2) 141-150. 

Tolerance, with continued heavy use, and a withdrawal syndrome occur (depression, anxiety, sleep disturbance, tremor and other symptoms). Many users find it very difficult to abandon cannabis. In studies of self-administration by monkeys, spontaneous use did not occur but, once use was initiated, drug-seeking behaviour developed. Subjects who have become tolerant to LSD or opioids as a result of repeated dosage respond normally to cannabis but... 

Psychological dependence with intense compulsive drug-seeking behaviour is characteristic of even short-term use, but physical dependence is arguably slight or absent. Tach5q>hylaxis, acute tolerance, occurs. 

Pre-treatment with the NOS inhibitor N -monomethyl-L-arginine impaired responding for cocaine self-administration when the drug was available and the increase of drug-seeking behaviour upon abrupt cessation of cocaine availability observed in control rats significantly reduced after treatment with 2 /°-monomethyl-L-arginine (Orsini et al. 2002). 

Be alert to drug-seeking behaviour avoid using benzodiazepines for agitation... 

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