There are many mental disorders that involve our inability to assess instant gratification in contrast to long-term consequences. This article is about impulsivity versus reflection and planning in relation to drug abuse and addiction.
One of the fundamental and insidious problems with substance abuse is the horizon problem. This is the common inability among humans to see the results of immediate gratification in the long view. The horizon is too far away. It is easy to ignore.
The list of chronic conditions that share this mechanism is long and many come to mind: overeating and obesity, sedentary lifestyles; even behaviors like chronic financial mismanagement fit this paradigm. It seems as if evolution has wired us for near-term outcomes.
Edgar Rice Burroughs wrote a series of excellent novels about Tarzan, a human being raised among the great apes. Tarzan gained a few supra-human abilities from his simian upbringing — he retained many of the primitive skills that modern men underutilize. He was extremely agile, strong, and had keen, animal-like senses. Beyond this, Burroughs wrote about an ability that gave Tarzan extraordinary speed. It was the simple notion that Tarzan could act without thinking. He could do something instinctively, while his opponents were still considering action. This highlights a key evolutionary concept — the advantage of instantaneous action over consideration and planning.
In an environment where the immediate surroundings are flexible and fraught with danger, prompt action is a survival trait. Not only do the strong survive, but the quick also. To breed tomorrow, we must survive this day’s challenge, and not only this day’s, but this minute’s and this second’s threat.
Enter consciousness. While all animals can be said to have instinctual behavior and immediate reactions to at least some stimuli, man has planning and imagination tacked on. The more we are able to control our environment in the long-term, the less we have to rely on emergency action. Our decisions today can make tomorrow a better (and safer) place to live. The evolutionary advantage of quick response is partly supplanted by the advantage of hypothesis about the future and actions directed toward achieving it.
Unfortunately for mankind, the near-term is still with us. If it feels good, do it.
Solving the Horizon Problem
Social scientists and psychologists have come up with at least one method to address the horizon problem.
Because the problem revolves around an inability to make future adverse consequences as ‘real’ as present benefits, the idea is to bring the distant horizon closer. If you want to save money, but find it impossible to make an envisioned bank balance impact spending right now, move the act of saving closer to the temptation to spend.
In drug abuse prevention, this is used to link consequences to the gratification. Public Service ads – “This is your brain on drugs” – showing adverse effects try to highlight near-term consequences. These only work if the imagery is both powerful and retained. It is doubtful that someone at the point of lighting a crack pipe has a television commercial in mind.
Medically, addicts can be prescribed drugs that change the effect of their preferred substance. The oldest in use is Disulfiram – which blocks the metabolism of alcohol and ruins the experience. The breakdown of alcohol is modified so that acetone builds up in the body. Alcoholics know that drinking while taking Disulfiram will make them sick. Sick is good. Sick is an immediate consequence. (See: http://www.cochrane.org/reviews/en/ab007024.html for a meta-study on the use of Disulfiram for cocaine addiction.)
Varenicline, a nicotine receptor partial agonist, is used to treat smoking addiction with the same principle in mind – remove the near horizon benefits. For opiate addiction, Naltrexone can be prescribed (an opioid antagonist).
Problems remain. Addicts must be relied upon to regularly take the preventative medications. Some (Naltrexone) are available as subcutaneous implants to overcome this deficit. None are ‘cures’.
A major problem with trying to bring the long-term results of addiction closer to the drug taking event is that the brains of addicts are reshaped by the addiction process. A loss of normal dopamine metabolism means their ability to respond to normal (no drug) pleasurable events is impaired. In a sense, homeostasis for this population includes taking drugs. Anhedonia is the unwelcome result of abstinence.
The brain changes in response to repeated exposure to the addictive substance. D2 receptor activity and number decrease over time with cocaine, amphetamines, alcohol and heroin. Worse than this, changes in memory and learning that are linked to ‘reward circuits’ mean other stimuli, not directly involving drugs can induce craving and compulsion long after active addiction has ceased.
Addicts will often describe how a certain lighting or other seemingly unimportant environmental cue can trigger a strong desire for ‘their drug’. We have known since Pavlov how deeply ingrained behavioral training can be, and while more complex with humans, the ideas remain parallel.
Time and Impulse
Near and far horizons have to do with time. Ask any addict to reflect on the results of their addiction and they will agree it is a terrible curse. None will recommend addiction to a loved one. Across long scales, we are very good at seeing the damage. When the impulse to use arises, time is different. Suddenly, the past and the future disappear and there is only the immediate now – a now full of craving and need.
One way to fight addiction is to address this short-term crisis. If an addict can be saved from the immediate situation, the behavior may be prevented. They can overcome the impulse if it can be stretched out in time, allowing better judgment and rationality to intervene. This is why supervision and incarceration work. Addicts are physically prevented from using and the urges get somewhat weaker with each cycle of impulse and denial. When supervision or incarceration ends, the behavior is free to reemerge.
What is needed is training that allows for self-supervision. It is possible to learn how to get past the stimulus-response impulse by time-shifting. This method is similar to that used to control other impulse based conditions – “I’ll wait to gamble until this weekend.” There is a chain of behavior that can be short circuited if it can be delayed.
In the end, the horizon problem is best handled by either moving long-term repercussions closer to the act or by time-shifting the act farther from immediate payoff. Neither is easy to accomplish, but both have had some success modifying other behaviors.