Frequency, a neglected concept in drug treatment

Charles Slack, Ph.D. ([1])

To make an informed choice to commit myself to any drug-treatment program, I am entitled, perhaps obligated, to know in some detail whether and in what way the program will reduce my chances of relapsing into symptomatic drug use. Of course, I must accept that data will be woefully inadequate. Yet in the absence of good data (and even in the presence of bad misinformation) I can improve my decision-making by basing my choice on certain concepts.

This paper discusses A) the statistical concepts of frequency and probability, B) the treatment concepts behind chronic vs. acute symptoms and C) the motivational aspects of effectiveness and attractiveness.

Can I make decisions without good data?

The answer is a qualified “yes”. I can assess drug abuse and treatment programs even with poor or missing data providing I keep in mind the principles of inference that would apply were such data available. Employing imaginary variables instead of real, research-derived values will not give me definite answers with known reliability and validity. Nevertheless as guides for my treatment choices, conclusions founded on the six concepts in A), B) and C) above will have greater plausibil­ity than those based on some simplistic notion such as “success rate”. (Applying my six concepts can also reveal more precisely what data are needed to make truly informed choices).

A) Two statistical concepts

First I must consider the concepts of frequency and probability. In regard to my drug use, frequency of use is defined as a sum­mary over time of my repeated ingestion of similar dosages. My probability of future use is determined by observing my current frequency of use and represents the predicted likelihood of my ingesting the next single dose. ([2])

B) Acute vs. chronic symptoms

Addicts often enter treatment because of a critical life situation rather than because of chronic use. Overdose, acute social distress, criminal charges/convictions, suicide attempts, severe accidents, financial crises etc. are common reasons addicts succumb to treatment. For example, I finally submitted to treatment because I’d lost my job and couldn’t get another one. I define these as acute symptoms.

Chronic symptoms are another matter. Most (if not all) abusers who present with acute symptoms are also chronic users. However chronic users commonly deny their chronic symptomatology. I for one was in complete denial about my obsessive thoughts about, as well as my compulsion to use, drugs. Frequent drug use was not a reason for my undergoing treatment. Nevertheless, to prevent future crises, my chronic drug use also needed to be reduced, preferably to zero. Reducing chronic use requires treatment different in kind from acute treatment.

Acute vs. chronic treatment

Acute abuse such as overdosing can be the result of a single critical use whereas chronic use is caused by frequent previous doses. The same distinction must be applied to psychological and social problems. A life crisis may be the result of a few bad choices, even a single major mistake but bad habits, even minor ones can eventually be deadly. But just as detoxification will not ensure abstinence, treatment to help me extricate myself from a disastrous life situation will not by itself cure bad habits that in turn may cause my next critical blunder (possibly worse than the last). Nevertheless, if acute treatment can prevent future crises, all the better: the longer acute treatment lasts, the more effective it is.

So I need two different types of treatment:

  • Effective acute drug treatment to recover from my chemical, social and personal crises. This treatment, although one-off, should be as long-lasting as possible to prevent further crises in my future life.
  • On-going treatment to prevent further chronic drug use.

Acute treatment must be effective and long lasting

Acute symptoms are related to the concentration of dosage, and the intensity of life crises. Treatment for acute problems must be effective in alleviating the crisis, and long-lasting to prevent similar crises from returning. Most rehabilitation efforts correctly assume that effective acute treatment is best undertaken during a drug-free period after detoxification.

Chronic treatment must reduce future abuse

In contrast, treatment for chronic abuse (preventing relapse) must continually reduce future frequency. The key concept, frequency, applies to treatment as well as drug use. This means that frequent use demands frequent treatment. ([3]) Chronic use requires repeated treatments. Reduced future abuse is best delivered by continuing, efficient, frequent, short-term treatments. Of course, it is important how we define “treatment” and “use” in the context of chronic use.


To keep it simple, I want to define chronic treatment as an activity or influence that reduces the probability of future use (Pu). In contrast, acute treatment is defined as an activity or influence that facilitates recovery from, and prevents future occurrence of, a chemical, social or personal crisis. In this context, I want to define “drug use” as the behaviour of ingesting, injecting or inserting a mind- or mood-altering substance into the body by any means. ([4])

Most rehabilitative efforts try to combine acute and chronic treatment. Since nearly all known treatments seem to reduce Pu best (or only) when the treated person is to some extent not under the influence of a drug, a common rehabilitative paradigm can be outlined:

  1. Pre-treatment assessment;
  2. Detoxification (if necessary);
  3. Social prohibition, physical restraint or biochemical blocking ([5]) against use during treatment;
  4. Activity and/or influence geared to alleviate and prevent future acute crisis situations (acute treatment);
  5. Activity and/or influence to reduce Pu (chronic treatment);
  6. Release/aftercare (chronic treatment);
  7. Post-release assessment.

It is important to realise that all treatments have a beginning and an end. Also, as regards the application of the concepts in this paper, no principle difference exists among, say, accepting a naltrexone implant, attending a two-year residential rehabilitation programme, answering an altar-call at a religious revival, attending an hour-long self-help meeting, or reading some anti-drug literature, as long as post-treatment Pu is reduced. (I will soon show that enrolling in a volunteer organisation, becoming a church-goer, joining a 12 Step fellowship, or enlisting in an on-going anti-drug campaign, are not actually treatments per se but sequences of treatments. The distinction is vital in regard to reducing Pu.)

Conflation of chronic treatment with acute treatment leads to errors in research, policy and personal behaviour. Salient among these errors is the hope/belief that any single effective treatment can be powerful and long-lasting enough to produce zero (or substantially reduced) post-treatment frequency. Applying the principles of frequency and probability, I believe I can demonstrate that the only treatment to reliably reduce future frequency of use is frequent future treatment.

An example case

Let’s say that I, as a chronic substance-dependent person, have been using an addictive drug daily for several years. Let’s also say that I undergo effective, residential detoxification and consequently become abstinent. On my first post-treatment day, the “first day of the rest of my life” with “nothing in my blood but blood”, I am totally committed to staying clean “one day at a time”.

Employing the statistical principles, I must now acknowledge a probability greater than zero (but less than before treatment) that I will use my drug the day of my release. This probability may be very low but it must be acknowledged. Let’s assume it to be one chance in a hundred. ([6])

By merely recognising this probability, I am not (yet) proposing a “probabilistic model”. So far I am merely discussing my future in terms of frequency and am, therefore, required to take into account my present (very low) Pu (relapse). That’s the good news.

The bad news

Making no further assumptions, if the probability of my use (Pu) remains unchanged at 1/100, I must also predict with some certainty that I am likely to use (relapse) sometime within the next one-hundred days or so. Given one chance in one hundred of it happening and given one hundred chances, it (whatever it may be) is likely to happen. That is the bad news.

Of course, if I had good data I would have a better basis for predicting my future. ([7]) Still no amount of good data will lessen my generally gloomy, long-range future because, as long as my abuse is defined in terms of frequency greater than zero, my potential for relapse must also be defined in terms of probability greater than zero.

Of course, after leaving the rehab, Pu is sure to vary up and down. Some actions and influences will work to decrease Pu. Other actions and influences will increase Pu. For example:

  • My life-style might improve which in turn might decrease Pu.
  • If I associate with users, Pu might increase through group influence or peer pressure.
  • New ex-addict and other non-using friends may influence my behaviour so as to reduce Pu: positive peer culture.
  • Some drug-free days might increase Pu by increasing cravings.
  • Yet if I resist the cravings so that a day goes by without use, Pu is likely to decrease: nothing succeeds like success.
  • Drinking alcohol might increase my Pu: weakening resolve.
  • Tougher drug laws might consequently decrease my Pu. Research reports, symposia and countless policy discussions all deal at length with legal and paralegal issues concluding that laws influence behaviour.
  • Proper actions/attitudes on the part of my relatives might decrease my Pu: family support is vital to recovery.
  • Finally, I hope my state-of-the-art rehab has trained me to engage in behaviours and expose myself to influences that decrease my Pu.
  • Scores, perhaps hundreds of other good and bad activities and influences could be added to this list.

Still, no matter how my Pu varies up and down, unless Pu definitely falls, given enough time I can be quite certain that I will eventually use my drug. At this point I might well take umbrage: does one day’s use automatically mean a complete relapse?

Sticking with my concepts, I am forced to admit that, because I am a chronic addict, even a single day’s use is likely to raise the probability of future use ([8]). This is simply a feature of the fact that future abuse is related to chronic past use. Each subsequent use then raises the probability of future chronic use, shortening the average time to next use. In this way a single use escalates into frequent use and chronic relapse.

  • Even when treatment is effective in eliminating chronic drug use for a period of time, the likelihood of relapse is high simply because a single use tends to increase the probability of future use.

Thus it can rightfully be said that chronic drug-abuse has a huge number of “causes” since even before a drug has been consumed, all behaviours and influences that increase Pu can rightfully be called causes. Also, by this definition, allowing Pu to remain the same by not doing anything positive about my recovery can also be a cause of relapse. To be safe from relapse, I must engage in activities, and expose myself to influ­ences, that decrease Pu.


Remember “treatment” is any behaviour or influence that decreases Pu. Watching an anti-drug movie, or even an anti-drug TV commercial, might tend to lower Pu slightly. Among activities likely to reduce Pu, helping others is extolled by those who have tried it as well as by professional experts ([9]).

Frequency of drug use is usually expressed as an average number of uses over a time period, (e.g. twice a day, four times per week, once a year). However it can also be expressed as a time period over which I may have used or not used (e.g. two weeks between shots, every other day, a month without relapsing). Because the expressions are reciprocal, I can go one step further and actually predict a distribu­tion of probable times for my initial use (relapse) after any given treatment. That means I can reasonably assign a “minimum time to relapse” for any given treatment. An effective long-term residential treatment, such as my state-of-the-art rehab, might provide a minimum time to first relapse of a month or more. A weak treatment such as simple exhortation in a self-help group might have a mini­mum time of less than one day. Even without data, I can now plausibly establish some standard for myself regarding how many “mini-treatments per week” I might need to reliably protect me from relapse at some level of confidence.

Weak treatments

As I try to lay out a program of frequent “top up” mini-treatments for myself, I discover paradoxically that, weak treatments require more frequent attendance. Employed often enough, weak treatments can ensure steady abstinence. Let us assume, for example, that a self-help group meeting has a median time to first relapse (Tr) of one week. Perhaps Tr varies from two days to two weeks making it a very weak treatment. Nevertheless, as long as I attend three times a week, I have a good chance of staying clean indefinitely.

Different treatments, different criteria:

I can now make important statements about criteria of the two types of treatment I need:

a) In critical treatment for my acute drug abuse lasting effec­tiveness of treatment is the important factor in preventing another acute crisis;

b) In continual treatment for my chronic abuse defined through frequency of use, frequency of treatment is more important than lasting effectiveness.

c) With regard to my chronic abuse, a “treatment” for me is any repeatable activity or influence that reduces my Pu (increases my Tr).

d) Treatment for my chronic abuse b) is always a matter of “upkeep” rather than “cure”.

e) As an addict, I have proven my ability to form habits. This extends to good habits as well as bad ones. Once I a “frequent-treatment habit”, I have a good chance of staying clean for life. ([10])

Attractiveness of treatment

It now seems obvious that the weaker the treatment, the more often I must habitually attend. But who wants to go to a weak treatment? Weak treatments are unappealing to those who are serious about their recovery. At this point I must consider another variable, treatment attractiveness. Frequency of attendance can relate as much to attractiveness as to effectiveness.

A professional counsellor recommends a 12 Step group to me. I attend a couple of meetings and decide that it may be OK for others but it is not right for me. The counsellor and I con­clude that the group is ineffective. But the group has a very high success rate for those who do “ninety meetings in ninety days”. Rather than ineffective, perhaps it was simply unattractive. Of course, attendance depends on attractiveness. However attractiveness often also increases with frequency of attendance! If I were to attend more meetings, I might change my mind. My treatment policy must clearly distinguish between attractiveness and effectiveness.

We now return to a vital distinction introduced earlier: treatment for critical abuse vs. treatment for chronic use.

Treatment policy

As I implied earlier, treatment policy that conflates acute treatment with chronic treatment leads to errors in terms of dollars and lives. Except for implants, treatments effective for detox and post-detox are too expensive and time-consuming to be applied at the frequencies required for a use-free lifestyle for chronic users. I need a continuing sequence of rapid, attractive, cheap, painless, ubiquitous, treatments. The important thing is frequent attendance on my part. Given a minimum time to first relapse of just a very few days, I might profitably attend an hour-long treatment every day for some months after detox, and then perhaps twice a week for a year or so, followed by twice a month thereafter. Exactly which treatment? Experts have their preferences but my preference is more important – providing my choice is within my budget and continues to increase Tr that all-important average time to first misuse.

The message

This paper has a message: avoid the first drug. No matter how many years have elapsed since my last use, I continually “treat” myself to avoid future use. How often and how intensely I engage in activities that increase my Tr is a matter of how thoroughly I want to protect myself from relapse. Fortunately, the longer I am abstinent, the more mini-treatments I discover. I have discovered, for example, writing a paper can lengthen my Tr. Although relapse is a life-and-death issue, less-than-serious influences can be effective mini-treatments. I recently heard that, “When hit by a railway train, the first car is the one that kills you not the second or third.” The analogy is ridiculous but it works for me. The first drug does the damage.

What about combined treatment?

Keeping in mind that acute treatment and chronic treatment have different objectives, a treatment facility such as a drug-rehab or detoxification unit can markedly improve service by engaging clients in frequent chronic treatments of a kind that continue after release. From the rehab’s point-of-view this may be seen as “aftercare” although to be effective the “care” must continue indefinitely. Another problem with “after care” is its frame of reference. The professional frame of reference is one where a “carer” provides care to a “client”. To continue after the person ceases to be a client, he/she must now care for him/her self. Furthermore, self-orientation being a trap for many addicts, merely looking after one’s own interests fails to increase Tr. To increase Tr, roles must reverse: the former client now caring for others. The best, and perhaps only, way to ensure such unceasing role-reversed aftercare is through fellowships.

Fellowships are not treatments

A “fellowship” is a voluntary network of like-minded people who share common goals and meet regularly. The Australian Psychological Association is a fellowship as is the Coalition Against Drugs and most religious groups. A 12 Step fellowship like Alcoholics Anonymous or Narcotics Anonymous should not be considered a treatment per se. Such a group is an association that happens to administer many treatments frequently to its members. Unlike a single treatment, a 12 Step fellowship supplies a variety of mini-treatments and unlike, say, a residential rehab, continues to administer them indefinitely. ([11])

For such reasons treatments cannot be directly compared to fellowships. Worse than comparing apples and oranges, comparing a treatment to a fellowship is like comparing an orange to a basket of fruit. A car service (treatment), no matter how thorough, can’t be compared to a car-club (fellowship) whose members maintain their cars to a standard. After any car service your vehicle is in good shape but will require another service in time. Joining the car-club might mean continually maintaining your car through regular servicing. The two don’t belong in the same category.

In the 1990’s it was popular in some academic circles to say that AA is ineffective because only a small proportion of alcoholics referred to AA remain sober. But a fellowship is something you must join. Among alcoholics who join AA a high proportion remain sober. ([12])

Attractiveness of Fellowships

It can be a grave mistake to write off a particular fellowship as ineffective even when a client quits. More frequent meetings usually increase the possibility that the client will find someone with whom to feel a sense of belonging, and want to return. Also helping fellowships to become more convenient, lower in cost, easier to access, have better amenities, etc. might well make them more attractive. If a fellowship is known to reduce Pu to some extent and is cost-efficient and accessible, attendance may profitably be encouraged even when its mini-treatments have short minimum times to first relapse.

What about controlled use?

Controlled (occasional use, recreational use, weekend-only use, etc.) can be shown to have low sustainability by the defining concept that each use increases the probability of future use. Apparent controlled use may occur by chance but then future use is likely to actually escalate. Controlled use should not be recommended because:

  1. In the absence of good statistical evidence proving otherwise, we must assume each “controlled” use to increase Pu.
  2. Controlled-use fellowships are very rare and very transitory. Compliance is difficult to ascer­tain.

What about compulsory treatment?

Weak treatments must be attended more frequently than effective treatments. If compulsory treatment for chronic use is weaker than similar voluntary treatment, then compulsory treatment should be made more frequent than voluntary treatment. This argument may seem counterintuitive to those most needing compulsory treatment, but it is true nonetheless.

I have tried where possible to avoid referring to the addicts’ mental processes and states of mind, preferring behavioural frequencies and probabilities. However, it needs to be stated that acute compulsory treatment allows the mind to clear so that better decisions will be made regarding future chronic treatment. In any case, compulsory-treatment proposals must be analysed in terms of frequency and probability of first misuse and relapse. Although they may not lower Pu as much as voluntary treatments, given frequent attendance over longer time, compulsory treatments can be highly effective. When and if compulsory treatments are justified, they should be made longer, more frequent and more available – and, of course, more attractive.

What about prevention?

Although preventative measures obviously differ content-wise from treatments, the arguments regarding frequency, probability, effectiveness and attractiveness are the same for both. We must assume that everyone exposed to drugs is vulnerable to some degree. Prior to first use one is less vulnerable than after first use. After frequent use, one is more vulnerable than ever. At any given time, each person at risk of first use has an asso­ciated probability of first use other than zero. Over enough time that probability will express itself as a frequency greater than zero. Drug prevention is a chronic problem demanding repeated solutions. Constant preventative measures are required on all vulnerable populations to ensure a drug-free future. Likewise, just because someone has only used once or twice and seems to have quit does not indicate “prevention.” Given enough time (longer perhaps than for the chronic user) the “resilient” person is likely to use again. And Pu will escalate unless preventative measures (“treatments” of some kind) are frequently brought to bear.

Summary and Conclusion

When the concepts of frequency and probability are ignored, drug risks are obscured, the perception of drug harm is minimised and expectations of treatment success are overestimated.

Treatment for the acute symptoms of abuse is very different from treatment for its chronic aspects. The former demands long-term effectiveness to prevent future crises. The latter requires frequent application to prevent future drug use/abuse. When “treatment” and “fellowship” are conflated, successful recovery programs are disparaged and the probability of relapse (Pu) increases.

Attractiveness can be as important as effectiveness in reducing Pu, particularly in regard to treatments for chronic drug use. Unattractiveness may reduce frequency of attendance but increased frequency also improves attractiveness.

Consideration of these concepts strongly suggests certain shifts in private thinking and public policy. In particular I suggest:

1) Base conclusions on their underlying statistical concepts.

2) Don’t confuse unattractiveness with ineffectiveness.

3) Define a “treatment” as any behaviour or influence that decreases Pu after treatment ceases. Increase avail­ability and frequency of weak treatments. Frequency, attractiveness and availabil­ity of mini-treatments are more important to recovery from chronic addiction than the lasting effectiveness of lengthy acute treatments.

4) Support existing fellowships including non-professional self-help groups. Assist fellowships to become more attractive and more frequent.

5) Develop new, attractive fellowships and other vehicles for frequent delivery of low-cost treat­ments.

6) Combine acute treatment with chronic treatment by directing detoxification and rehabilitation facilities to act as entry points for fellowships.

7) And finally, don’t take the first drug under any circumstances.


[1] I have purposefully written this paper from the point of view of an addict or drug abuser who wants to achieve abstinence and remain totally drug free indefinitely. Typically the subtext of most treatment research reveals a slightly different point of view, namely that of the professional whose personal habits are assumed to be irrelevant.

[2] If, perhaps, I am trying to achieve some form of controlled use, occasional use, “weekend-only use”, asymptomatic use etc., I will define “abuse” in terms of some frequency greater than once. I might, for example, want to say that a single use on Saturdays and Sundays is OK but more than that constitutes a relapse. (Although my health and safety will likely best be served by defining abuse as a single use, as long as my abuse and relapse are defined in terms of frequency, the key concepts can be applied.)

[3] – It might seem that naltrexone implants would be an exception since the agonistic effect of the O’Neil has been known to last up to nine months. However the effective phase of any blocker is best considered as its “treatment phase”. When we talk about reducing future use, we refer to a post-treatment phase after the implant has ceased to block the receptors.

[4] – With regard to treatment with an opiate blocker such as Naltrexone, this behavioural definition of “drug use” would be the ingestion, injection or insertion of the drug even if the drug had no physiological consequence. Of course, during naltrexone implant treatment, we would expect the misbehaviour to decrease (extinguish) since it is not being reinforced. However, we know from many animal and human studies that “extinguished” behaviour resumes high frequency almost instantly after a single reinforcement is delivered. This means that when naltrexone wears off, a single drug use will quickly escalate into chronic abuse.

[5] – i.e. naltrexone implants. Of course, a blocker like naltrexone blocks the physiological consequences of use not the actual behaviour such as swallowing, injecting, or inserting the drug.

[6] – If one hundred daily users recently went through my rehab and only one person used on the first day out, I can say that my treatment is better than no treatment for ninety-nine out of one hundred cases. Assuming I am similar to the others, I can estimate my probability of misuse to be in the order of 1/100.

[7] – I understand that a one-year follow-up is usually accepted as standard for residential drug treatment facilities. I also understand that few if any such studies have adequately been performed. In general however, most sophisticated experts expect less than a five- percent success rate (95% relapse) within the year.

[8] – If, as sometimes happens, once-off use appears to decrease the probability of future use, we would have to conclude, by definition, that the drug no longer acted in an addictive manner. In fact, addictive drugs remain addictive. Actually they appear to get more addictive never less so. In my experience, Pu is rarely reduced by relapse and then only during treatment, not afterwards.

[9] – Criminologist Donald Cressey’s “retroflexive reformation” applies as follows: when “addict A joins with non-addicts to help addict B, it is A who is helped most”. When I volunteer to work for a few hours each week at the outreach centre, “sharing” with other rehab clients will probably reduce my Pu. Even a phone call to my “sponsor” (instead of a dealer) can be an effective mini-treatment. Of course, an hour spent with a good counsellor is also likely to reduce Pu. But according to Cressy (and 12th Step members), counselling others reduces Pu more than being counselled. See Donald R. Cressey, Changing Criminals: The Application of the Theory of Differential Association, The American Journal of Sociology, Vol. 61, No. 2 (Sep., 1955), pp. 116-120.

[10] – Without going into detail, let me say that, through frequent attendance to fellowships and other activities, I have maintained continuous abstinence from drugs and alcohol since 03/03/1976.

[11] An association, such as the Australian Medical Association, a political party, or a church congregation, influences the behaviour of its members by involving them in activities and influences that are analogous to treatments.

[12] The primary criterion for membership is verbal: you are a member when you say you are. Another more stringent criterion requires attending ninety meetings in ninety days.

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