Anti-depressants for Dogs?

The use of antidepressant type medications for treating behaviour problems in dogs seems to be increasing significantly. It is quite common now to come across people asking for help with their dogs’ behaviour and to find that the dogs have already been prescribed an SSRI (selective serotonin reuptake inhibitor) or TCA (tricyclic antidepressant). Even puppies as young as 3-4 months are apparently being prescribed these drugs quite readily by some vets.

On the other hand, I have also seen trainers declaring that dogs should never be medicated for behaviour issues and that doing so is tantamount to abuse, so I thought it would be a good subject to examine in a bit more detail. After all, we need to be able to make informed choices about our own dogs and professionals need to know when it is reasonable to refer clients to vets or veterinary behaviourists to discuss the possibility of including medication in a behaviour modification treatment plan.

Firstly, it is important to note that behaviour professionals are not vets – we do not prescribe medication ourselves. However, a good behaviour qualification includes training in psychopharmacology by specialist vets, so that we are able to identify situations where pharmacological intervention may be helpful or necessary and so that we have sufficient understanding to be able to explain to the client’s vet, why we are suggesting they look at this option.

Secondly, I feel it would be remiss not to mention that much of what was believed about the chemistry of depression and other mood disorders, and the mechanism for managing them with antidepressants, has now been shown to be incorrect. The reality is that we don’t really understand what causes depression or other mood disorders, because the evidence shows that reducing serotonin levels in healthy individuals with no depression, does not cause them to develop depression and there seems to be no clear correlation between serotonin levels and depression. I do think it is important that when we consider the use of psychopharmacology, we are cognizant of the fact that we are delving into a space where things are a little murky and there are no clear answers as to how these medications work in the cases where they do appear to have benefit. This is therefore a subject we need to consider carefully and without being overly confident. For those interested, the papers below provide a comprehensive review of what is and is not understood about depression and the role of SSRI's in treating it:

https://www.nature.com/articles/s41380-022-01661-0 

https://pubmed.ncbi.nlm.nih.gov/36938996/ 

Over the years, I have on quite a few occasions referred clients to veterinary behaviourists or to their own vets because I felt that pharmacological intervention was necessary for helping to address a behaviour problem. I have written to clients’ vets explaining why I believe that a particular dog would benefit from being given an SSRI or tricyclic antidepressant. I am therefore not against using pharmacological intervention, but I do have concerns that whereas in the past it was sometimes rather difficult to get vets to prescribe antidepressants for dogs, it now seems a bit too easy.

As I said before, it is very common these days to find that dogs have been placed on SSRI's or tricyclic antidepressants with no behaviour assessment and simply as the result of a 10-minute vet visit. It seems that it is now fairly routine to go for a normal vet visit, explain that your dog has some behaviour problem (anything from mild anxiety to severe aggression) and have the vet prescribe psychiatric medication. I find this deeply concerning and I'm going to explain why.

Behaviour is complex. Most behaviourists book a 2-hour consultation with a client for the initial assessment. We usually spend a good 90 minutes asking 1000 questions. We don't just want to know what the dog is doing that is currently a problem for the owner, we want to know every detail of the dog's life. When it comes to figuring out why a dog is struggling with something, we have to consider every factor that could be influencing their behaviour: We need to know if the dog's physical needs are being met. We need to find out about exercise, diet, sleep patterns and overall health. Then we want to know whether the dog's emotional needs are being met. We want to know whether the dog has enough social contact, whether the dog has enough opportunities to explore and engage in normal species-specific behaviour, whether the dog plays or has opportunities to play and whether the dog has enough mental stimulation. We also want to know whether the dog's lifestyle may be increasing stress due to activities the dog is engaging in or situations the dog is being put in which could trigger fear, frustration or general anxiety. Then we want to understand the dog’s learning history. We want to know what experiences the dog has had in the past which could contribute to how the dog feels about certain things now. Has the dog experienced trauma? What training methods have been used with the dog? What has the dog learnt about which behaviours work and don't work from past experiences?

There are so many factors which contribute to behaviour issues and most of them are a combination of environmental influences and genetic predispositions. Trying to understand how a dog has arrived in a particular situation and what may be the best way of helping them overcome that, takes a lot of digging, assessment and careful consideration. I certainly would not feel comfortable speaking to an owner for 5 minutes and then advising them to place their dog on a medication – especially medication which is not without potential side effects and for which we do not fully understand the mechanism of action. Yet this is exactly what seems to be happening all the time when dog guardians obtain psychiatric medication after a routine vet visit. Surely there needs to be some more in-depth assessment process that takes place before these drugs are handed out.

Of course, there may be urgent cases, where a dog is crippled by severe anxiety or depression or physically harming themselves – immediate intervention with medication may absolutely be the right way to proceed in such cases and failing to do so may actually be a welfare issue. However, these cases are rare – most of the dogs that present with behaviour issues don’t fit into this category.

We have to think carefully about what we are doing, and it is vital that we are aware that medication can NEVER be a replacement for improving a dog’s lifestyle. IF A DOG IS MISERABLE, STRESSED OR ANXIOUS BECAUSE OF VERY REAL CIRCUMSTANCES, THOSE CIRCUMSTANCES NEED TO BE MANAGED AND ALTERED, PRIOR TO CONSIDERING MEDICATION OR IN CONJUNCTION WITH MEDICATION. MEDICATION IS NOT A REPLACEMENT FOR GIVING A DOG A GOOD LIFE.

Another concern is that medication that boosts mood can create more problems than it solves, if the underlying emotional state during the problem behaviour or the dog’s general mood state has not been correctly evaluated. One of the most common reasons people want to use medication is to treat aggression. However, while fear-motivated aggression can sometimes be improved by relieving anxiety or boosting confidence and certain frustration-related types of aggression do seem to respond well to SSRI’s, it has to be kept in mind that anti-anxiety and antidepressant drugs tend to cause “disinhibition”, which means that dogs can be less inhibited in their responses. This reduced inhibition can lead to dogs using a more serious agonistic display when they feel threatened. If you want to understand disinhibition, think about a drunk person doing things they would not normally have the courage to do, or the reported suicides “caused” by certain anti-depressants. Furthermore, if aggression has been used for a while as a strategy to cope with a situation and it has become a well-learned behaviour, making the dog more confident can make the behaviour even more reinforcing. I have also seen cases where dogs medicated to manage a “flight” response to something, have switched to a “fight” response e.g. a dog that previously ran away from another dog in the home was put on an SSRI and then began attacking the other dog instead. The point is that we really do need to assess situations carefully, consider all possible outcomes and explain these to dog guardians, so that if they choose medication, there is INFORMED CONSENT (at least on the part of the human in the equation).

Finally, speaking of informed consent, the reality is that we cannot ask dogs how these drugs make them feel. We can take into account the listed potential side-effects and we can listen to what humans who take these medications have to say. On the one hand there are many people who have experienced incredible benefits from antidepressants and who believe that for them, these drugs are lifesaving. On the other hand, there are many who report debilitating side effects and have had enormous trouble trying to get off these drugs. Whether any of that is relevant to dogs, who knows? At the very least though, we should be looking out for any warning signs that the medication may not be agreeing with them, and we also have to remember that, just like humans, dogs must be very gradually weaned off these medications in order to avoid emotional distress.

To sum up, I am not against the use of medication to help to alleviate emotional distress in dogs, which leads to behaviour problems. I continue to talk to clients about this option, when I feel it is appropriate to improve welfare. However, I don’t believe that putting a dog onto an SSRI or TCA should be done lightly, without a full and thorough assessment and without addressing environmental factors which may be contributing to the problem. This seems a reasonable approach to me, which seeks to first do no harm and places the welfare of the dog over human convenience.

POSTSCRIPT: This post is not an attack on vets. I understand that vets are under a lot of pressure to meet clients’ needs, to alleviate perceived suffering and to see many patients every day. They are also constantly being marketed to by pharmaceutical reps who obviously paint many of these drugs in only the most positive light. Vets are often doing the best they can in difficult circumstances. However, a better-informed public will put less pressure on vets and make better decisions for their animals - that is the reason for my post.