Rash impulsiveness and reward sensitivity as predictors of treatment outcome in addiction

The abuse of substances is a major, global problem. It is a problem in terms of
the huge financial costs due to medical care, criminality and loss of
productivity. Moreover, the enormous emotional burden suffered by addicted
individuals and their environment, cannot be expressed financially.
Because of the extent and severity of the problems caused by addictive
substances, research into treatment of addiction is extremely relevant.
Treating substance abuse disorders has proven to be difficult. Addicts
frequently refuse to come in to treatment, and even when they participate in
clinical or outpatient programs, results are often limited. Although patients
can seem to be motivated, relapse and drop out are common. This is an important
fact because remaining in treatment is associated with abstinence. It appears
to be extremely useful to try to identify variables that predict the outcomes
of the treatment of addiction. Once there is understanding of the mechanisms
contributing to the success or failure of treatment, it is possible to take
individual differences into account in conceptualizing treatment plans of
individual patients.
Integral research into the predictive power of the promising (two-factor) model
of impulsivity (as proposed by Loxton and colleagues and Franken & Muris) in
the field of addiction treatment, has not been done yet.
In the present study Rash Impulsiveness an Reward Sensitivity (the two factors
in the above mentioned model) will be used as predictors of treatment outcome
in addiction.

Goals:
-contribute to the further understanding of the concepts of Rash Impulsivity
and Reward Sensitivity by investigating them in a clinical population: are
these concepts valid in a clinical population as well?
-examine whether Rash Impulsiveness or Reward Sensitivity (or both) are
variables that predict treatment outcome and therefore are important in
improving the diagnostics and treatment of drug addicts

Questions:
Primary question: Are Rash Impulsiveness and Reward Sensitivity distinct
variables in a clinical population?
Secondary question: Do Rash Impulsiveness and Reward Sensitivity have
predictive value in treatment of substance dependence, independently of each
other?

Hypotheses:
-According to the theory of Dawe, Gullo and Loxton (2004) it is to be expected
that Rash Impulsiveness and Reward Sensitivity are distinct variables.
-It is expected that rash impulsiveness is a predictor of treatment outcome:
individuals with high levels of this trait perform worse in treatment.
-It is hypothesized that high levels of Reward Sensitivity are predictive of
treatment drop-out.

Participants will be inpatients residing in the *Boumankliniek*, a clinical
facility of Bouman Mental Health Care in Rotterdam. Patients will be selected
and asked to volunteer while staying at the Detoxification section. After their
detoxification, they will be transferred to the Rehabilitation ward. Patients
will be asked to fill in questionnaires, will be tested neuropsychologically
and will be interviewed during the first three days of their stay at
Rehabilitation. During their stay, subjects will be monitored from the moment
they enter Rehabilitation.
Three months after initial assessment, participants will be interviewed once
again, to investigate the relative change in use of addictive substances.

not applicable