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Psychological dependence is a state that involves emotional–motivational withdrawal symptoms, e.g. anxiety and anhedonia, upon cessation of drug use or certain behaviours. It develops through frequent exposure to a psychoactive substance or behaviour, though behavioural dependence is less talked about. The specific mechanism involves a neuronal counter-adaption, which could be mediated through changes in neurotransmittor activity or altered receptor expression. Withdrawal symptoms can be attenuated by environmental enrichment and physical activity. Psychological dependence is not to be confused with physical dependence, which induces physical withdrawal symptoms upon discontinuation of use. However they are not mutually exclusive.

Symptoms
Symptoms of psychological dependence include:


 * Anxiety


 * Panic attack
 * Dysphoria
 * Anhedonia
 * Craving
 * Stress

Development
Psychological dependence is caused by consistent and frequent exposure to a drug or behavioural activity. It is often associated with effects of drug use, but it can also be caused by behavourial activity e.g. pornography.

The mechanism that generates the dependence involves a neuronal counter-adaption, which is localized to the area where the drugs positive reinforcement stems from. This adaption could occur either as a change in neurotransmittorhyperlänk activity or as an altered receptor expression.

Change in neurotransmittor activity

Studies has shown that in rats going through ethanol withdrawal, stimulant withdrawal or opioid withdrawaal, the nucleus accumbens showed lower levels of serotonin and dopamine than controls. These decreases are associated with depression and anxiety.

In anatomically distinct areas of the rat brain, withdrawal causes lower levels of Gamma-Aminobutyric acid, neuropeptide Y and higher levels of dynorphin,  corticotropin-releasing factor, as well as norepinephrine. All these changes are linked to psychological dependence.

Altered receptor expression

Changes in receptor expression has also been linked to withdrawal. For example, in rats suffering from nicotine withdrawal it could be observed a down regulation of α6β2*n-icotinic acetylcholine receptors in the mesostriatal dopaminergic pathways.

Methods for reducing dependence
A study examined how rats experienced morphine withdrawal in different surroundings. The rats was either placed in an standard environment (SE) or in an enriched environment (EE). The study concluded that EE reduced depression and anxiety withdrawal symptoms.

Another study tested whether swimming exercises effected on the intensity of the psychological morphine withdrawal of rats. It concluded that the anxiogenic and depressive state of the withdrawal was reduced.

Distinction between psychological and physical dependence
The major differences between psychological dependence and physical dependence are the symptoms they cause. While psychological dependence causes emotional motivational withdrawal ,physical dependence entail somatic symptoms e.g. increased heart rate, sweating and tremor. Different drugs varies in which dependence they induce (see table 1).

Psychological dependence and physical dependence are distinct entitities. However, describing them as mutually exclusive is not satisfactoryinc, since the notion that mind (psychological) and body (physical) are separated is flawed. Empirical studies has shown that even cravings, which are widely associated with psychological dependence, involves a physiological element.