Skip to Content

Help! Why is My Dog Acting Paranoid All of a Sudden?

Veterinary reviewed by Elizabeth Racine, DVM.
This post may contain affiliate links. Read more here.

Dogs act paranoid all of a sudden due to underlying fear, phobia, separation anxiety, or physical health issues.

Although the complexity of a paranoid dog hasn’t been thoroughly analyzed, it’s a fact that some canines suffer from this.

Fear as a defense mechanism is widely spread among dogs and it’s not that easy to eliminate.

Most aggression cases are fear-based and it’s a real issue.

Continuous exposure to fear produces phobia and/or paranoia.

What can make a dog act paranoid?

Dogs with phobia experienced persistent fear and now they constantly anticipate it even when the trigger isn’t apparent.

Persistency isn’t a hard and fast rule.

Even a single fearful experience can turn into a phobia that surpasses rational responses.

Both fear and phobia can make a dog paranoid, though with phobia the symptoms are much more expressed.

So many triggers can be responsible for the condition but I’ll try to guide you through them all.

Symptoms of a paranoid dog are:

  • Pacing
  • Drooling
  • Panting
  • Loss of bladder control
  • Lip licking
  • Yawning
  • Flattened ears
  • Tucked tail
  • Avoiding eye contact

No dog should be blamed for developing fear, anxiety, or phobia.

They understand the world much differently than we do so we need to learn how to help them cope with whatever intimidates them.

Why is My Dog Anxious All of a Sudden?

Many medical and non-medical reasons cause sudden anxiety in dogs.

Dogs can get unsettled due to stuff that seems mundane to us. No age, gender, or breed is excluded from this.

Dogs can act paranoid all of a sudden and one indicator might be that your dog is acting like he's seeing things.

Let’s look at the most common reasons for a dog’s mental distress with paranoid behavior as a resulting outcome.


A dog that is afraid is a dog that often starts acting paranoid.

Most commonly dogs fear sudden loud noises, objects/people that look suspicious, unpleasant smells, etc.

Fear appears when the trigger is in the dog’s proximity.

Different dogs show different symptoms of fear.

Some hide in dark and isolated places while others become alert and aggressive.

If you know your pet well enough you might have an idea of what produces the sudden onset of fear.

When you can’t find the exact cause right away, don’t blame yourself.

It’s advisable to talk to a veterinarian and even take your pup for an exam.

A vet along with a canine trainer can guide you in relieving the level of fear and stress in your beloved furry friend.

Trauma and Phobia

Although age isn’t the key factor, many dogs develop phobia as a result of a traumatic experience when they’re puppies or between 1 and 3 years of age.

Anxiety crosses the line and turns to phobia due to incidents like mistreatment, abandonment, abuse, etc.

Phobic dogs make it hard for themselves even when the trigger for the phobia is nowhere to be seen or heard.

Whatever the cause is, this type of anxiety takes a great toll on your dog’s physical and mental health.

We often see chronic phobia due to past trauma in rescue dogs.

Some of them had abusive owners and now anything that might remind them of past experiences produces paranoid episodes.

Never try to medicate your phobic dog on your own.

Once professional trainers and veterinarians discover why and when anxiety occurs, they should give you instructions on how to desensitize the pet first.

Mild cases of anxiety may be improved by using a dog thundershirt.

Separation Anxiety

Separation anxiety is pretty common in dogs and it’s easy to diagnose.

Whenever dogs with this condition are left alone they can start acting paranoid and turn to destructive or clingy behavior.

For some, it takes just a few minutes for the symptoms to kick in, while for others it takes a few hours.

The outcome is the same either way.

If the problem is not promptly addressed, it can take a serious toll on your dog’s mental health (as well as on your furniture and relationship with your neighbors).

The dog simply thinks that the owner won’t ever come back for him.

Either a rescue already had separation anxiety or the owner didn’t train the pup to stay alone.

Breed Predisposition

Some dog breeds are naturally more anxious compared to others.

A 2020 study among 13,700 Finnish pet dogs has reinforced the idea that there might be a genetic component when it comes to anxiety.

These breeds include the Lagotto Romagnolo, Wheaten Terrier, Spanish Water Dogs, Shetland Sheepdog, Miniature Schnauzer, and mixed breeds.

However, other breeds commonly assumed to be more nervous include German Shepherds, Dalmatians, Huskies, and Border Collies.

Highly intelligent and energetic dogs are prone to anxiety if underexercised and not mentally stimulated.

Keep in mind that paranoid behavior out of nowhere can occur across every breed.

However, every individual’s temperament is different, no matter the breed.

Lack of Socialization

The first few months of a puppy’s life are very important for proper social and environmental experiences.

Letting this key segment slip can make a puppy habitually fearful as he grows up.

One of the most common culprits of an anxious dog is poor socialization.

Various stimuli during young age give a dog the general idea that the world is filled with surprises that can be loud, sudden, and weird looking but cannot hurt him.

Puppy classes and walks in parks or around the city are a great way to avoid these problems.

Social paranoia in dogs can also be caused by separating a puppy too early from the mother and other littermates.

This happens when you take the dog away before he reaches 8 weeks of age.

Bad Course of Training

Luckily, more and more people rely mainly on positive reinforcement as means to train their dogs unlike the old methods of using physical punishment and violence for bad doggy behavior.

Punishing the dog’s normal puppy behavior – like accidents inside the house – can produce all sorts of phobias in the long run and the only product of the process is a paranoid dog.

Moreover, this may also result in a general distrust towards the owner and a lack of bonding.

Health Problems

Quite a few health conditions can make your dog turn paranoid all of a sudden including encephalitis, hypothyroidism, diabetes, and thyrotoxicosis as the most frequent behavior modifiers in dogs.

Paranoia in dogs can be one of the reasons why this small dog suddenly acts anxious and hides under a brown blanket.
Photo by Lindsay Helms on Shutterstock

The most important thing worth remembering is that dogs can suddenly become jumpy, alert, and paranoid when they suffer medical issues.

Both discomfort and pain are things that can turn an otherwise relaxed dog into a paranoid one.

Every disease is a potent stressor that can easily alter the canine’s behavior.

We humans also experience psychological problems when we are physically sick.

If it’s a health condition causing your dog to be anxious and paranoid you can expect some symptoms that will tell you something isn’t right.

Why is my dog not acting like himself? Has he been eating properly for the last few days?

How long since the last vet check-up?

Answer these questions and if there is the slightest possibility of a health concern don’t wait to make an appointment at the vet’s office.

Especially when your dog is older and has never before had behavioral issues you should have him thoroughly checked.

Senior dogs with nervous system disease can experience anxiety.

Toxic substances leading to acute poisoning may alter the dog’s behavior in minutes.

My Dog is Acting Like He is Seeing Things

If your dog is acting like he is seeing things, he may actually hear them before actually seeing them.

However, dogs who persistently act like they see things might suffer from fly-snapping syndrome, eye issues (i.e. floaters), or neurological problems, perhaps even causing hallucinations.

A dog’s hearing capabilities are four times stronger than a human’s.

They can hear something distant and try to focus on it by looking in that direction.

The frequencies your dog is picking up cannot be heard by people so he might look strange as if he sees things.

A syndrome called Fly-Snapping can be the reason why your dog seems like seeing things as well.

The FS Syndrome is caused by epilepsy and seizure.

There is a possibility that the syndrome is hereditary.

Eye problems like vitreous floaters are conditions when collagen fibers clump within the vitreous and cast shadows on the retina.

In this case, your dog does see these clumps that appear as flies in front of his eyes which makes him fix his gaze strangely.

Hallucinations can appear because of neurologic disorders or certain medications and make a dog keep looking up and around.

What to Do If Your Dog is Acting Weird and Restless?

If your dog starts acting weird and restless you first need to make sure he doesn’t hurt himself on sharp objects, the stairs, etc.

In the meantime, do a little brainstorming to try and figure out the potential cause and any coincidences.

If you are still not able to find what the cause is, take your dog to the vet asap.

You can sometimes spot a dog acting like something is crawling on him as a response to boredom, so not all weird behaviors are as serious as one might think.

Dog Suddenly Scared of Something in the House

Dogs can be suddenly scared of recently added objects inside the house such as a new sofa, rug, plants, or even just moving something in the house, especially if’s something that provided comfort to your canine like the dog bed or crate.

Another cause of this onset of fear can be unfamiliar noises, often causing a dog to hide or bark compulsively if not socialized well enough.

However, anything that’s causing uncertainty in your dog can make him suddenly scared.

If your dog is acting paranoid for a prolonged time, make sure to take your dog to the vet for a check-up.

Evaluate whether or not external factors contribute to this (new objects inside the house, stress, boredom, etc.).

Disclaimer: This blog post does not substitute veterinary attention and does not intend to do so. I am not a veterinarian or pet nutritionist. If your dog shows any sign of illness, call your vet.

About Danielle

Equipped with 5+ years of expertise as a Rottweiler owner, I partner with licensed veterinarians and trainers to share research-backed and actionable advice for you and your furry friend.


Thursday 3rd of November 2022

Hi, my Terrier Cross has been with us since a puppy - he is 13 next March. He has been on Apoquel for a few months and (with the vets approval) has been double dosed every day for the last 4 weeks. Over the last week or so his behaviour has changed alarmingly. He can’t settle, is jumping at nothing - like he has seen a ghost, he is scratching at wall plugs and will not lie still unless someone is with him to snuggle into. He seems to be a very unhappy dog all of a sudden. It is firework season but as he has been for all of his life he is not bothered by them - barely flinching when the occasional one is let off nearby. I have stopped his Apoquel and am giving him a week to see if this brings him round. I have read of occasional aggression Olin dogs on this, but he has not displayed aggression himself. Any thoughts or suggestions would be welcome.


Friday 4th of November 2022

@Danielle, Thank you Danielle. I am going to give him a few days off tge meds to see how he is. Either way I will take him the vet next week. If he seems better I will need to discuss alternatives for his skin condition. If he’s still manic/paranoid etc, a different conversation will have to take place. Thanks again.


Thursday 3rd of November 2022

Hi Ken, please talk to your vet about this, I'm not a vet and can't provide medical advice. While the reaction might be related to the meds (dogs can get more sensitive to sights and sounds), it might be a completely different health issue. Your vet should run a couple of diagnostics and ask more questions about the behavior to see if meds need to be continued, paused, switched, or if other treatments might be necessary.

Susan Gunn

Saturday 22nd of October 2022

Hi, I have a 11 month old Maltese dog. I have had him since he was 8 weeks old and have taken him to puppy classes and everything has been going very well until the last month. He had an accident in his cage and I didn’t find it until the morning. I was very careful not to upset him and just carried on as normal getting him out, taking him out to our garden to go to the toilet. I them cleaned him with a bath and totally cleaned out his crate and bedding. I didn’t make any fuss as I felt it was my fault and not his as he had no way of telling me. Ever since he is totally freaking out going in the crate at night, he will go in and out during the daytime but is absolutely petrified at night. How can I help him? Susan.


Sunday 23rd of October 2022

Hi Susan,

it sounds like soiling his sleeping space may have impacted your pup negatively. It's usually no issue and just needs a bit of positive reinforcement to get your dog to like the crate again.

This article is more focused on when your dog is truly acting paranoid, not just when a negative training experience happened.

That being said, if you suspect anything could be wrong medically with your pup, please consult your vet.


Wednesday 28th of September 2022

Hello, my dog is a 7 year old chihuahua mix. He suddenly started acting different. It’s almost like he doesn’t trust me he’s always watching my every move. He seems scared of me I passed by him and he started screaming like if I hit him. He’s never been abused or anything like that. I’ve had him since he was born and never acted this way up until now. The other night I noticed I was petting him and he was falling asleep but fighting it and suddenly I felt like he wanted to attack me in a sneaky way so I got up and stepped away. He’s definitely not the same and I don’t know what’s wrong with him 😔 please help! 🙏


Wednesday 28th of September 2022

Hi Monica, since you've had your dog as a pup and no abuse, I'd definitely consult my vet to see if it's a medical issue. That said, think about whether or not your dog did in fact experience something negative related to you (attacked outside, stepped on his tail, screamed at him) or was he somewhere where other people had access? It's just a possibility to keep in mind, usually properly socialized adult dogs are robust enough to handle these events but some sensitive dogs really suffer from seemingly harmless actions.

If the vet says everything is okay, consider consulting a behaviorist because you need to have somebody look at it in person.

Cheers, Danielle


Saturday 17th of September 2022

My baby boy Bubby is 15yo PooChon. He has always been on the OCD side. He likes to chew &lick his paws/tail until he gets sores on them. He is now hard of hearing. But prior to this, he was freaky about loud noises. So I had the thunder shirts & calm for him as well my other 2 dogs. A 13 yo LhasaPoo & 9yo MaltiZu. Bubby has always been a mommy's boy. Last Labor Day weekend he had a bad sore on his back paw again. I had it all wrapped up, in short I was leaving town for a girl's getaway, the hubbs was supposed to stay with him pretty much 24/7. He didn't, Bubby freaked out, somehow got the bandage too tight. He was a shivering, whimpering mess when I got home. I know that emotionally scarred my poor liitle guy. Anywho. So for right now it's the strangest thing. His hearing is heightened to where if i set a glass down down he jumps & runs off. he acts like he is seeing things that I can't &then he freaks out & starts shaking. He is truly frightened. You can see it in his eyes. I keep his thunder shirt on him 24/7 give him calm sometimes.. I just feel so helpless. We've tried a couple of meds for the OCD chewing/ licking etc in the past. But I didn't them. Today was the worst yet. He just gets frantic if he sees whatever it is, & hears whatever it is &he can't get to me fast enough! If I'm up he follow me, problem is I'm in a fracture walking shoe &he's almost tripped me a few times. He tries to jump on my lap when I'm on the toilet! You can literally see the fear in his eyes. As long as he's on my lap, he's fine I get up... he does too. Do you have any ideas ? Sorry I know this kinda jumps around a bit. I'm just a concerned fur-paw mommy


Wednesday 21st of December 2022

@Annette, has wonderful products, I use them. I'm not affiliated with the company. Just really love the products for our 2 snauzers.


Thursday 22nd of September 2022

Hi Annette, it really sounds as if your pup could benefit from having a vet check them out. Due to age, I'd definitely consider medical issues. The other part might just require desensitization to noises as well as training to be alone to work on a potential separation anxiety issue.

The chewing & licking could indicate an underlying medical condition such as allergies, inflammation, but also mental issues. Is your dog currently being treated by a vet? What's their opinion? Maybe checking in with a behaviorist might make sense too.


Tuesday 28th of June 2022

My dog is a 2 yr old chocolate lab. She is all of a sudden hesitant about going outside or to certain areas when she goes outside. Could it be something Mayne she smells or what.


Saturday 2nd of July 2022

Hi Erica, first I'd make sure that there were no negative experiences on walks, easier if you're the only person walking her. It might be something she smells or sees but it's hard to tell. You might want to check out this article on why dogs refuse to walk. It actually has over one hundred comments, some are similar to what you're describing.

Cheers, Danielle