Substance addiction (alcohol and drug dependence) is classed as a mental illness alongside depression, anxiety, bi-polar etc. From what I understand, the repetitive use of any type of drug will result in the formation of a specific neural pathway, upon habitual use of the substance the pathway will strengthens. In response to you referring to addiction as a "brain disease", doesn't really make much sense in my opinion. I mean its clinically classified as a mental illness, so it seems to me like you're just saying the same thing in a different way.
A
"brain disease" refers to a
disease with a biological origin in the brain. The assertion that addiction is not a "brain disease" is equivalent to the assertion that the form of behavior commonly referred to as "compulsive drug use" (i.e., the behavior that characterizes all forms of drug addiction) is not a disease at all – since the brain is responsible for all behavior elicited by humans which is not
innately reflexive – but a form of behavior which is either (1) an internally-driven, willful choice which is not compulsive in any way and/or (2) an externally-driven consequence of one's environment.
The 1st statement by itself is equivalent to asserting that there is no loss of objective, goal-oriented decision making capacity in addicts and they simply want to abuse drugs despite the consequences (i.e., an addict's
executive functions are completely intact and he or she is therefore fully able to exert
cognitive control over their behavior in order to stop using drugs at any time, if they so choose). The 2nd statement by itself is equivalent to the idea that humans lack free will (i.e., that the behavior of both addicts and non-addicts is entirely determined by
stimulus control of behavior with no goal-oriented decision making capacity; in other words, any healthy individual who is placed in an addict’s environment will become an addict since they can’t choose not to elicit the same behaviors).
If both of those statements are assumed to be true, it would imply that treatment-seeking addicts (i.e., individuals who have chosen to stop using an addictive drug after initially choosing to non-compulsively "abuse" an addictive drug for some time) would be able to easily and effectively stop using addictive drugs, and never relapse, simply by moving far away to a new location that is devoid of drugs and drug cues (e.g., a small town with a non-existent prevalence of street drugs); this is because operantly and classically conditioned behavioral responses (i.e., stimulus control of behavior) are entirely driven by external/environmental stimuli, which would no longer be present under those circumstances. The occurrence of cravings would not trigger relapse in a treatment-seeking addict under these circumstances because an addict would be fully capable of exerting cognitive control over their behavior by
choosing not to act on that desire, exactly like non-addicts are able to.
All of the things I've described above are obviously nonsensical; that's due to the fact that an addict's drug use behavior stems from pathological drug-induced changes in their brain, resulting in impaired executive functions, amplified sensitivity to
rewarding stimuli (most of all to the addictive drug that they use; operant reinforcement is governed by reward cognition), and reduced sensitivity to
aversive stimuli (e.g., negative outcomes associated with drug use; operant punishment is governed by aversive cognition), among other changes (e.g., those associated with drug dependence/withdrawal). Since all of these changes involve cognitive functions which are directly responsible for decision making and action selection, behavioral changes occur as a direct consequence; in particular, behavioral responses to the environment will change even when the environmental conditions that trigger those behaviors remain static (e.g., a rat with free access to meth in an operant conditioning chamber will gradually use more and more provided that it starts to use it regularly). Hence, treatment-seeking addicts will fail to adhere to treatment even if they truly or desperately want to stop due to the fact that their behavior has become very strongly controlled by rigid/inflexible learned behavioral responses (aka
prepotent responses) which have become very difficult to "unlearn" (i.e., undergo
extinction) due to the aforementioned changes in cognition. So, returning to my previous example, even if an addict moves to a town with a very low prevalence of drugs, their lack of ability to exert cognitive control (specifically,
inhibitory control) over their behavior when a craving arises can and usually will result in them taking a trip to another location where they can acquire and use the drug to which they're addicted.
With all this said, addiction isn't purely based on what's going on in your head, it also is largely dependant on factors such as the surrounding environment.
Every single thought and sensation that humans experience and every single behavior (excluding innate reflexes like the
knee-jerk reflex) that humans elicit is 100% determined by what's going on in their head (NB: the spinal cord mediates innately reflexive behavior). The environment drives human behavior through the systems of neural pathways that give rise to operant and classical conditioning (i.e., the reward and aversion systems) precisely because those two learning processes are responsible for shaping behavioral responses to the environment which are not unlearned/innate reflexes. Moreover,
it's not the environment that changes when a healthy person who uses an addictive drug turns into an addict; rather, the “thing” that changes when that individual becomes an addict is the structure and function of the
networks of neural pathways in the brain that (1)
govern their behavioral responses to the environment and (2)
govern their ability to inhibit behavioral responses to the environment in order to select behaviors in line with their goals.
THAT is why addiction is a "
brain disease".
