Abstract

In human medicine, psychiatric side effects among patients on corticosteroid therapy are widely reported,
but this appears to have been largely overlooked in the animal literature despite glucocorticoids being
widely used in veterinary medicine. Therefore the aim of the current study was to identify possible
psycho-behavioural changes in dogs treatedwith corticosteroids. Two different methodologieswere used. Firstly,
dog owners were asked to fill a 12 item questionnaire aimed at further validating the initial results of a
previous survey relating to changes seen when their dog was receiving corticosteroid treatment. In a second
study, a population of dogs undertook behavioural tests aimed at objectively identifying changeswhen receiving
corticosteroid therapy.
In the first study, a sample of owners whose dogs were receiving treatment for dermatological, orthopaedic or
other conditions evaluated their dogs' behaviour on and off therapy, using a seven point scale. The survey was
completed by 44 dog owners with dogs receiving treatment with a range of corticosteroid preparations (mainly
prednisolone and methylprednisolone) and 54 dog owners with dogs receiving treatment with other drugs,
mainly antibiotics and non-steroidal anti-inflammatory drugs. Dogs under corticosteroid treatment were
reported to be significantly less playful, more nervous/restless, more fearful/less confident, more aggressive in
the presence of food, more prone to barking, more prone to startle, more prone to reacting aggressively when
disturbed, and more prone to avoiding people or unusual situations.
In the second study, eleven “treatment” dogs were tested both before and during corticosteroid treatment with
either methyl-prednisolone or prednisolone to assess their sensitivity to a potentially aversive sound stimulus.
Eleven control dogs were also tested at the same time intervals in the same environment. Dogs were exposed
to a brief dog growl while they explored bowls containing food and their behaviour was video recorded.
Treatment dogs were found to investigate the area in the vicinity of the bowls for significantly less time and to
eat significantly fewer pieces of foodwhen on corticosteroids, compared to control dogs, after hearing the growl.
These results provide the first empirical evidence of possible adverse psycho-behavioural side effects in a
veterinary clinical setting following the use of corticosteroids, and suggest the need for concomitant behavioural
advicewhen these drugs are used in general veterinary practise to avoid the risks associatedwith these changes.