The earliest report of needle fixated behaviour dates back to 1929. Light and Torrance2
described patients injecting water, which they understood as a placebo for drug effect.
Pates et al3
studied 19 needle fixated subjects who when compared to 23 non-needle fixated individuals displayed significantly higher scores for sexual arousal and for whom injection had a greater significance than efficient delivery of the drug. Some individuals substituted inert substances for the drug and reported sexual arousal and obsessive compulsive disorder (OCD) symptoms associated with repeated injections.
The concept of needle fixation has been criticised as being a construct subsuming several different injecting behaviours under an elusive and broad definition of needle fixation as the ‘repetitive puncturing of the skin with or without the injection of psychoactive drugs via intravenous, subcutaneous or intra-muscular routes, irrespective of the drug or drugs injected or the anticipated effects of the drug’.4
Needle fixation is often missed in patients presenting with intravenous drug use and also seems frequently dismissed by clinicians. However, it is important because of the risks associated with frequent injecting behaviour, including blood borne viruses, septicaemia, thrombosis and abscesses, as well as the negative impact on the prognosis of intravenous drug use.
Several aetiological hypotheses for needle fixation have been postulated, including activation of the opioid system by the inert substance acting as placebo thereby resembling the action of opiates.5
Pates et al
suggest the ‘rush’ associated with injecting as a perpetuating factor.3
McBride et al
proposed that operant and classical conditioning could explain needle fixation.1
In their study, a high number of individuals reported heightened levels of anxiety prior to injecting and it is thought that the relaxation experienced afterwards reinforces the injecting behaviour. Secondary gains such as sexual pleasure, pain and social status might be linked to operant conditional processes and it appears that other social and environmental processes could also be explained by this model.1
However, whether learning theories are useful constructs to explain needle fixation remains to be seen.
Fluoxetine, a selective serotonin reuptake inhibitor, is indicated for the treatment of depression and OCD. In animal studies it has been shown that fluoxetine can suppress the development of morphine tolerance and dependence to antinociceptive effects of morphine.6
Improvement in ‘needle fixation’ behaviours in our case can be interpreted in this context. It may also be possible that complex inhibitory interactions between serotonergic and dopaminergic pathways in the forebrain have a role to play.7
These postulated neuropharmacological actions of fluoxetine may lead to reduction of reward directed behaviours.
At present there is little evidence for any effective treatment strategies or data regarding the prevalence of needle fixation. The current recommended treatment for needle fixation consists of cognitive behavioural therapy combined with cue exposure.3
The likelihood of successfully treating the patient described with a cognitive behavioural therapy based approach would be relatively low due to his borderline IQ, his limited insight into his difficulties and little motivation to change.
Cue exposure consists of presenting the patient with paraphernalia used for injecting either imaginatively or directly and subsequent systematic desensitisation. It is only recommended in conjunction with cognitive behavioural therapy as it might otherwise lead to arousal and further reinforcement of needle fixated behaviour.3
Whether fluoxetine or other psychopharmacological interventions could add anything to the armamentarium currently used to treat needle fixation remains to be seen.
- Needle fixation is frequently missed in clinical practice.
- Needle fixation is associated with serious complications, such as thromboembolism, septicaemia and blood borne infections.
- To date there is no effective treatment available.
- Treatment of needle fixation might improve outcome of intravenous drug use.
- Selective serotonin reuptake inhibitors might play a role in the treatment of needle fixation.