You would think that the answer is obvious and that you would say that indoor cats are healthier than indoor/outdoor cats. It’s more subtle than that. This is a big subject but perhaps it is useful to divide the health problems into two categories (1) trauma (2) everything else including parasitic infections, infectious diseases, self-mutilation, metabolic syndrome and so on. If I have missed something please comment. This article has been written from memory.
Trauma
Trauma in this context means injury or death. It’s pretty obvious that indoor/outdoor cats are more likely to suffer injury or death due to a variety of causes, the most obvious of which is no road traffic accidents unless they escape and that does happen. And it might be worth stating that if an indoor cat escapes, they are probably more prone to trauma because of confusion and uncertainty.
And in countries like America there are predators which attack and kill outdoor cats. All these health problems are not present for the indoor cat except perhaps with a minor qualification namely that in multi-cat homes there may be friction between cats leading to fights which in turn might lead to injury. I wouldn’t expect fights to break out that often in multi-cat homes because from my reading on the subject, it is normally a dominant cat which bullies a timid cat leading to the timid cat retreating and hiding which avoids conflict.
On average, it is hard to disagree with the argument that full-indoor cats live longer than indoor/outdoor cats. This is because they avoid death by trauma. But this leads to the enduring discussion as to whether it is better to live a happier short life or a longer miserable life. I’m not saying that full-time indoor cats are miserable. I’m just illustrating the point about contentment versus discontentment and how that impacts decision-making. Bearing in mind that very few homes are enriched for cats I’d argue that indoor cats are generally less content than indoor/outdoor cats.
Diseases, mental well-being, obesity, diabetes, OCD, urinary tract disease, ringworm
Indoor/outdoor cats are more likely to pick up a contagious disease from another cat with whom they come into contact and who is infected. Although this possibility is not exclusively the domain of indoor/outdoor cats. Sometimes people adopt another cat and introduce them to their multi-cat home. The incoming cat may carry a disease which is not been detected. And infectious diseases can spread to all cats in a confined environment with devastating consequences. There have been some horror stories of all shelter cats being euthanised to eradicate an infectious disease and when ringworm takes hold in a multi-cat environment it is damned hard to get rid of.
Also, cat owners can bring fleas into the home on their person and therefore indoor cats are not immune to getting a flea infestation. Although it’s less likely.
Diseases like rabies are going to be very rare in full-time indoor cats but it would be rare for an indoor/outdoor cat to get rabies as well. But the chances are higher for a cat allowed outside. That said, indoor cats can escape sometimes which means that they temporarily become an indoor/outdoor cat with all the attendant possible health problems including rabies where the disease is present.
To recap, therefore, there is less chance of indoor cat contracting an infectious disease and a parasitic infection but the big problem which is barely discussed is that the environment in which the vast majority of indoor cats live is too sterile. It is too unnatural and this can create underlying health problems such as OCD which is manifested in self-mutilation through over-grooming due to stresses. And stresses can also cause cystitis, a UTI.
And boredom can lead to pleasure eating which in turn can lead to obesity which further in turn can lead to feline diabetes (type II) and of course there may be mental health issues which are incredibly hard to diagnose in domestic cats.
It is my belief that domestic cats can become depressed and stressed through a lack of stimulation in an unnatural environment. These are mental health issues. They are not like trauma which is very easy to see and diagnose. But if a cat is almost permanently pissed off because they’re banged up in a small home which is sterile and their owner does not stimulate them enough or interact enough with them, they are going to be living in an unhealthy environment.
Environmental management plays a big role in cat behaviour and welfare outcomes. That’s what the scientists would say. And maybe there are some indirect health issues here as well. For example, a cat becomes stressed and bored and becomes aggressive towards another cat or scratches furniture more often than they should do. Or there might soil the home because of inappropriate elimination due to separation anxiety. They may become aggressive towards people. All because they are stressed due to the environment.
And when a domestic cat exhibits this kind of behaviour, they might well end up being abandoned. That abandonment can take various forms: return to a shelter or ‘thrown away’ in the countryside somewhere. Both these outcomes impact the health of the cat dramatically. It may well lead to their death either at a shelter through euthanasia because they can’t be adopted or through starvation when outside or because they are attacked by a predator and killed.
So, there is this nuanced picture which is not as black-and-white as one thinks when you compare the health of indoor/outdoor and full-time indoor cats.
Compromise is the best – the middle path
The best compromise in terms of overall cat welfare including physical and mental health is to keep a domestic cat indoors but provide a highly enriched environment combined with a catio or garden enclosure. This is a compromise which almost certainly results in the best outcome in terms of health because it eliminates the negatives of a sterile home environment which is a potential source of ill-health but adds the advantages of an indoor life. The problems of multi-cat homes need to be factored in to the ‘health equation’. There are far more cat mental health issues in cats in multi-cat homes than in homes where there is a single cat and a good owner and where the cat is allowed outside (ideally supervised – what about a lead?).
Some more indoor versus indoor/outdoor cat discussion are below.
