Psychoactive drugs are drugs that contain chemical substances that cross the blood brain barrier. They have effect to the central nervous system as it alters the function of the brain. They result in changes, in mood, perception, behavior and cognition. Most of the psychoanalytic drugs are used for recreation with a sole purpose of alteration of a person consciousness, as a tool to make one study than usual, as a way of augmenting the mind or it can be used for therapeutic purposes as a form of medication. Psychoactive drugs lead to subjective changes in consciousness and mood leading to a feeling of pleasantness to the user. This makes many users to abuse the drug because of such pleasant feelings. Examples of depressant drugs include Barbiturates Glutethimide Methaqualone and Chloral Hydrate. Stimulants drugs include caffeine, cocaine and nicotine. Opiate and hallucigenic drugs include morpheridine, dipipanone and tobacco. Differentiate drugs include glucosaminesulfate and sulfa drugs. Drug abuse is the use of drugs in a way that is not prescribed or in the recommended way. Drug addiction is a state where a person gets used to drugs in a way that the body cannot function properly without the drugs (Coon 94-96).
Classical conditioning is a learning process which happens through association that exists between an environmental stimulus and another stimulus that occurs naturally. Therefore, classical conditioning is a reflexive or automatic learning process whereby a stimulus acquires the capacity to trigger a response that was previously triggered by another stimulus. In order for classical conditioning to occur there must be unconditional stimulus that naturally and automatically triggers a response. Then, unconditional response occurs responding to the unconditional stimulus. Conditioned stimulus, which is previously, natural stimulus after it is associated with the unconditioned stimulus, then, triggers a conditioned response (Forsyth pp 94). Good example of classical conditioning is the ability a dog has to relate the sound of a bell which does not have any meaning to the dog previously with the presentation of food which has a lot of meaning for the dog. Therefore, a dog is able to learn from the association that exists between the bell and food which leads to salivation after the dog hears the bell because the connection is already made.