We all know what a spectrum is: one color on one end another on the other end and a lot of transitions in between. The idea of illnesses being like a spectrum as opposed to dichotomous (has it or doesn’t) is gaining in mental health. Recently, in discussing changes for DSM-V, psychiatry’s diagnostic bible, it seems that those who are writing about the future diagnosis of substance use disorders are beginning to look at it as a spectrum. Sounds great. There’s only one problem with it; it doesn’t describe reality.
Making a spectrum out of the illnesses that have been put in the substance use category of DSM IV is like making a spectrum out of an apple, an orange, a lemon, a lime, a blue fruit (if there was one) and a plum. You’d have the colors but your mixing different things. Sometimes a metaphor can be taken too far.
First there is the assumption that the substance use disorders actually hold together and are separate from other disorders in the DSM. It is an assumption and not one that is supported by the evidence of recent studies. DSM is concerned with behavior, not with biology. Illness is biology from which behavior can manifest, but it’s the biology that comes first. So before we look at the substance use disorders and say they can be made into a spectrum we have to see if they are separate from other things that look like addiction (overeating, compulsive sex, compulsive gambling, etc.) and are the same as each other (that substance abuse is the same as addiction, only less of a problem).
The evidence I’ve seen suggests that it can’t be done. Biologically, addiction to opioids and addiction to sugar binging have more in common than addiction to opioids and abuse of opioids. There are a lot of reasons that people with normal brains choose to do stupid things with drugs, but there’s a real commonality about why people with addiction use. That commonality extends beyond drugs to anything that makes the reward system go “Bam.” When we try to put people with normal brains who abuse substances in addiction treatment they don’t understand what we’re talking about. When we try to put addicts in treatment with people with normal brains they get confused and try to “use like a normal person.”
Next is the idea, inherent in the “spectrum” that there’s a real progression from lesser to greater levels of illness. Imagine a minor form of addiction that gets worse the more you use and becomes a greater form of addiction. There’s no doubt that addiction is progressive and progresses faster with drug use, but the question is does that mean it’s on a spectrum or just the same thing at a different point in the person’s life cycle. Diabetes follows the same sort of course, but you don’t see doctors calling diabetes a spectrum where non-insulin dependent is better than insulin dependent. In fact, that’s old thinking. Now we have endocrinologists trying to understand the underlying biology, poor insulin production vs insulin receptivity, and tailoring treatment to meet the underlying need, not just “how bad” the illness is.
With addiction it has been clearly shown that the criteria for “substance dependence” (addiction) show up sooner in addicts than the criteria for “substance abuse” (not addiction). So abuse isn’t some lesser form of the same thing that leads to a bigger form of the same thing. Actually the evidence of that study comes from the same minds now trying to shoehorn the issue into a spectrum. Rather than taking the results of the study to question the very idea that addiction always follows abuse instead of being a separate entity, they are trying to salvage a drug based definition system that has no biological basis.
When DSM-III first laid out the current nomenclature and diagnostic system it was 1981, 7 years before the first evidence for a biological basis of addiction was discovered. It’s time to stop trying to prop up the old pre-scientific idea and ask what the data actually shows. That addiction is one disease and that there are different substances, including food, or behaviors that are the focus of any given person’s illness and what “drug” the addicted person uses depends on what gives them the relief from a deficit in the reward system, not choice of drug.
Instead of trying to paint the pretty picture of spectrum, we should be looking at what the evidence says so we can provide the best care to patients with this chronic illness.