Dried blood spot analysis for the monitoring of subjects affected by “dual diagnosis”

Due to the increasing consumption of illicit drugs, those cases of subjects affected by dual diagnosis, namely simultaneously suffering from mental disorders and substance abuse problems, represent an urgent concern for physicians and psychiatrists. It is evident that substance abuse is associated with a significant risk of developing psychiatric syndromes and that an early beginning of abuse habits leads to proportionally higher hazards and illness severity. Dual diagnosis cases are particularly frequent in critical settings, like for example the jail, where the lack of personal freedom facilitates the onset and the worsening of mental disorders and abuse habits. Risperidone (4-[2-[4-(6-fluorobenzo[d]isoxazol-3-yl)-1-piperidyl]ethyl]-3-methyl-2,6-diazabicyclo[4.4.0] deca-1,3-dien-5-one) is one of the most frequently prescribed drugs worldwide for the management of schizophrenia and specifically in dual diagnosis patients. It is one of the so-called "atypical antipsychotics", mainly metabolised in the liver to 9-hydroxyrisperidone, a compound with similar activity. For this reason the most clinically meaningful chemical parameter during risperidone therapy is the "active moiety", i.e. the sum of risperidone and 9-hydroxyrisperidone blood concentrations. Active moiety determination in dual diagnosis patients is an important data to be considered, with the aim of personalising and optimising the pharmacological therapy, together with a reliable monitoring of the main classes of drugs of abuse and their metabolites (cannabinoids, cocaine, amphetamines, etc). For this purpose an advanced method, based on dried blood spots (DBS), has been implemented and coupled to LC-MS/MS. The high sensitivity and selectivity of LC-MS/MS and the high feasibility of DBS sampling represent a powerful and effective analytical strategy in dual diagnosis cases, where patients are non-compliant with psychiatric therapies and also abusers. Results seem to be satisfactory and applications are providing useful data for the monitoring of dual diagnosis patients.