Background Stiff-person syndrome (SPS) is an uncommon and disabling disorder characterised by progressive rigidity and episodic painful spasms involving axial and limb musculature. An autoimmune pathogenesis is suspected because of the high prevalence of particular autoantibodies. SPS treatment is mostly based on benzodiazepines, baclofen, immunosuppressants and intravenous immunoglobulin. Clinical experience with the cannabis derivatives tetrahydrocannabinol (THC) and cannabidiol (CBD) in patients with multiple sclerosis is accumulating steadily, but there is no current literature about its efficacy for SPS. The authors report a patient with seronegative SPS successfully treated with THC-CBD oromucosal spray.

Purpose The aim of this study was to check the effect on his quality of life (QoL), before off-label drug treatment with THC-CBC and after 14 months of treatment.

Materials and methods In 2003 electromyography revealed continuous activity in agonist and antagonist motor unit both axial musculature and abdominal region, without periods of relaxation. Laboratory analysis included required autoimmune profiles in order to exclude paraneoplastic syndromes, tumours and other autoimmune diseases. These were negative both in serum and CSF results. The patient was diagnosed with seronegative SPS. In 2009 the patient became wheelchair-bound and standing was only possible with support. Due to unsatisfactory treatment results a multidisciplinary group decided on off-label drug treatment with THC-CBD oromucosal spray (Sativex), with the patient's informed consent. Besides monitoring at the Neurology Department, compliance with the treatment and results of the treatment were also monitored at the Outpatient Pharmaceutical Care Unit (OPCU). The patient's target after titration was an average dose of two sprays, which achieves optimum symptom relief. Now this has been established, the patient can adjust his dose according to how he is feeling on a day-to-day basis, and is better able to perform his daily activities. In stressful situations the patient requires up to 6 sprays. QoL was evaluated with the Spanish version of the SF-36 health questionnaire, which is divided into 8 dimensions.

Results Improvement was verified in the eight dimensions. Role-physical, bodily pain, social functioning and role-emotional were the dimensions in which the effect was more noticeable. After 14 months' treatment with THC-CBD oromucosal spray the patient has acceptable mobility and autonomy.

Conclusions In conclusion cannabinoids can be a therapeutic option to treat spasticity associated with neurological diseases such as stiff-person syndrome. Our patient's quality of life has improved remarkably although more information is needed about this particular use.