Codeine Symptoms and Warning Signs. Codeine is a deceptively dangerous drug that is found in many prescription cough medicines and painkillers. Drugs that stimulate and also block opioid receptors (for example, pentazocine) reduce the effect of codeine. Such drugs should not be combined with codeine. Such drugs should not be combined with codeine. For the Consumer. Applies to codeine: oral solution, oral tablet. Along with its needed effects, codeine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention. • Many patients who have codeine dependence have underlying mental health issues or chronic pain –initial use of codeine may have been to manage these problems • Anecdotally, high co-occurence of early age psychological trauma, history of abuse, 2 thoughts on “ Codeine Abuse Causes, Statistics, Addiction Signs, Symptoms & Side Effects ” Mick February 2, 2015 at 2:58 am. Hi, I’ve been on codine (panadine forte) for approximately 8-9 years due to a severe back injury. Psychological dependence is much more complicated and can occur when the brain becomes adapted to the repeat codeine use. All opioids increase dopamine in the brain which helps to regulate behaviors and reinforce those that bear repeating such as eating, or having fun. Like other opiates, codeine also has an itchy, sedating effect. A codeine user may be drowsy, especially if he (or she) is using a high dosage or is abusing the drug. His heart rate will slow down, which can lead to fainting or dizziness. Psychological: Sometimes individuals who become addicted to substances such as codeine are self-medicating in order to deal with an untreated mental disorder. Codeine is used in an attempt to control unpleasant side effects of the underlying mental disorder. Cognitive and Psychological Effects of Prolonged Codeine Use. The long term effects of codeine use on the mind can include a myriad of mental health problems, ranging from mild to severely debilitating. Codeine itself has weak affinity for the μ-opioid receptor. Its principal analgesic actions are mediated by the affinity of morphine for the μ-opioid receptor, though other therapeutic and adverse effects are produced by activation of other opioid receptors.