Addiction Treatment Blog

In 1954, Olds and Milner discovered that there appeared to be pleasure spots in the brain. Implanting electrodes in certain areas of the brain, through which a rat can give itself an electric current by pressing on a lever, produced in most brain areas nothing of note. In some areas, however, the rats seemed keen on the effects of self-stimulation and, in some cases, if left to their own devices would self-stimulate to the exclusion of all else – even food and drink.

As mentioned, noradrenaline was discovered in the brain in 1954. In 1959, a second catecolamine, dopamine, was identified, which was shown to be deficient in Parkinson’s disease.

The later mapping of dopamine-containing neurones has shown that they too, like noradrenergic neurones, tend to originate in a discrete area, the ventral tegmentum. Some of these neurones run to strictly motor areas of the brain and constitute the nigrostriatal system, and it is loss of nerve calls in this pathway that leads to Parkinson’s disease. Read more…

If the induction of appetites and cravings, which has been hitherto seen as psychological dependence, is not in fact any more psychological than the physical dependence that underlies withdrawal, is there any other psychology involved? There almost certainly is (1). For example LSD, phencyclidine and many of the new designer drugs do not cause either type 1 or 2 physical dependence. Yet they are increasingly abused, despite evidence that many of these compounds may be fatal. Phencyclidine, for example, has led to a considerable number of fatalities and, despite not leading to any obvious euphoria, during the 1980s became for a period the second most common drug of abuse in the USA. Why?

Common to many of these drugs is the fact that they alter consciousness and, as a result, are interesting to take. On tis basis, one explanation that may account psychedelics, opiates or alcohol, there is a certain amount of playful activity. Read more…

Dependence

Before considering this in detail, we must exclude a type of physical dependence that occurs with a great number of drugs and ordinarily is of little consequence. Many drugs will cause rebound symptoms once they are discontinued. This happens particularly if they block receptors. This blockade leads to the blocked receptors becoming hypersensitive. When the blocking drug is then removed, these receptors are flooded with the normal neurotransmitter and they respond vigorously. It may take 48-72 hours for them to settle back down to normal.

Examples of this are the rebound phenomena that may occur with beta-blockers, such as propranolol, and the cholinergic rebound that may happen after stopping antidepressants with marked anticholinergic effects. Propranolol rebound may lead to palpitations, sweating and flushing. Cholinergic rebound may produce poor sleep and nausea or vomiting. These syndromes are not serious, and high doses of the relevant compounds are stopped abruptly. Read more…