Urinary neurotransmitter analysis in canine behavioural disorders

   Deviations in the neurotransmitter system are associated with numerous psychiatric disorders and neurological diseases. To evaluate neurotransmitter system function, urinary neurotransmitter screening is regularly used in human medicine, e.g. in patients suffering from mood disorders like anxiety and depression. In veterinary medicine anxiety disorders have a high prevalence in dogs. A non-invasive comprehensive neurotransmitter analysis may enable precise diagnostics of canine behavioural disorders and effective neuromodulatory treatment monitoring.

   The objective of this study was to establish and validate a non-invasive diagnostic tool where characteristic neurotransmitter deviations served as biomarkers for canine behavioural abnormalities. Urine samples of 100 dogs were analysed, consisting of a group suffering from behaviour-related problems in comparison to age- and breed-matching healthy controls. Quantification of urinary neurotransmitter levels was conducted utilising High-performance liquid chromatography Triple Quadrupole MS/MS technology. The behaviour profile of the dogs was determined using a standardized online questionnaire, composed of previously validated questionnaires (C-BARQ, ADHD-RS, DPQ, CCDR).

   Regression analysis revealed a hormonal influence on urinary neurotransmitter excretion. An age-dependent association between gender/castration status and urine neurotransmitter levels was found. No correlation between the neurotransmitter levels and the behaviour profile was found.

    The evidence from this study suggests that urinary neurotransmitter levels do not correlate with the canine behaviour profile. However, future trials with wide-ranging behaviour analysis and extended neurotransmitter screening in biological fluids, like blood or cerebral spinal fluid, may validate the neurotransmitter analysis as a valuable diagnostic tool for canine behavioural disorders.