Is Your Dog’s Bad Behavior Caused by a Health Problem?

Written by Jan on December 28, 2010 – 1:35 am

Is your puppy or adult dog acting strangely, being aggressive, fearful, phobic, hyperactive or depressed? Many of these and other canine “problem” behaviors can result from thyroid dysfunction, or a vaccine or drug reaction. Even food with a high sugar content can cause behavior problems, as it can with children.

Before calling your dog trainer to “fix” your dog’s problem, read what these three veterinarians (specializing in three different fields) have to say. Retraining may still be required, but check out your dog’s health first.  Maybe the behavior was caused by thyroid disease, vaccination or medication.  [Note: The highlights below are mine – Jan Rasmusen.]



“The principal reason for pet euthanasia stems not from disease, but undesirable behavior” wrote pet vaccination and thyroid expert, W. Jean Dodds, DVM.  Below is an excerpt from “Behavioral Changes Associated with Thyroid Dysfunction in Dogs” by Drs. Dodds and Linda P. Aronson:

… an association has recently been established between aberrant behavior and thyroid dysfunction in the dog, and has been noticed in cats with hyperthyroidism. Typical clinical signs include unprovoked aggression towards other animals and/or people, sudden onset of seizure disorder in adulthood, disorientation, moodiness, erratic temperament, periods of hyperactivity, hypoattentiveness, depression, fearfulness and phobias, anxiety, submissiveness, passivity, compulsiveness, and irritability.

After episodes, most of the animals appeared to come out of a trance like state, and were unaware of their bizarre behavior. … Investigators in recent years have noted the sudden onset of behavioral changes in dogs around the time of puberty or as young adults. Most of the dogs have been purebreds or crossbreeds, with an apparent predilection for certain breeds. For a significant proportion of these animals, neutering does not alter the symptoms and in some cases the behaviors intensify. The seasonal effects of allergies to inhalants and ectoparasites such as fleas and ticks, followed by the onset of skin and coat disorders including pyoderma, allergic dermatitis, alopecia, and intense itching, have also been linked to changes in behavior.

Many of these dogs belong to a certain group of breeds or dog families susceptible to a variety of immune problems and allergies (e.g. Golden Retriever, Akita, Rottweiler, Doberman Pinscher, English Springer Spaniel, Shetland Sheepdog, and German Shepherd Dog). The clinical signs in these animals, before they show the sudden onset of behavioral aggression, can include minor problems such as inattentiveness, fearfulness, seasonal allergies, skin and coat disorders, and intense itching. These may be early subtle signs of thyroid dysfunction, with no other typical
signs of thyroid disease being manifested.

The typical history starts out with a quiet, well-mannered and sweet-natured puppy or young adult dog. The animal was outgoing, attended training classes for obedience, working, or dog show events, and came from a reputable breeder whose kennel has had no prior history of producing animals with behavioral problems. At the onset of puberty or thereafter, however, sudden changes in personality are observed. Typical signs can be incessant whining, nervousness, schizoid behavior, fear in the presence of strangers, hyperventilating and undue sweating, disorientation, and failure to be attentive. These changes can progress to sudden unprovoked aggressiveness in unfamiliar situations with other animals, people and especially with children….

The major categories of aberrant behavior [are] aggression (40% of cases), seizures (30%), fearfulness (9%), and hyperactivity (7%); some dogs exhibited more than one of these behaviors. Within these 4 categories, thyroid dysfunction was found in 62% of the aggressive dogs, 77% of seizuring dogs, 47% of fearful dogs, and 31% of hyperactive dogs.

Our ongoing study now includes over 1500 cases of dogs presented to veterinary clinics for aberrant behavior. … findings confirm the importance of including a complete thyroid antibody profile as part of the laboratory and clinical work up of any behavioral case.

From Jan: Read Dr. Dodds entire article for more information. Listen to Dr. Dodds’ discussion of thyroid supplementation . Dr. Dodds evaluates and reads my own dogs’ thyroid tests. My vet draws the blood then sends it to.  Dr. Dodds interprets test results by breed, age, sex and activity — which no one else does. She writes that this interpretation “often yields an expected normal reference range for an individual pet that differs from the test lab’s generic broad reference range.”  And her nonprofit has great prices.  The complete panel she runs is called Thyroid 5™. This is much more complete than the simple thyroid results than is found in general blood tests.

Additional articles about thyroid disease by Dr. Dodds: 
The Effect of Hypothyroid Function on Canine Behavior 
Nutritional Management of Thyroid & Immune Disorders
Thyroid Disease and Autoimmune Thyroiditis



Patricia Jordan, DVM, VND, CVA, CTCVM & Herbology, is a vaccination expert and author of Mark of the Beast. She writes:

My experience as a practicing veterinarian for over 25 years, matched by Dr. Stephen Blake (37 years) and Dr. Richard Pitcairn (40 years) — has been that of watching vaccines result in disease in animals — and behavioral changes.

UC California at Davis recently finished studies proving the development of anger, aggression and anxiety in both animals and humans following vaccination. This should not be surprising as the mercury in vaccines (yes, it is still there) and aluminum are neurotoxins which are in combination synergetic. Aluminum opens the blood-brain barrier allowing mercury, aluminum and viruses (both intentional and unintentional contaminants) into the brain. The ensuing inflammation that develops is, well, encephalitis!

A French study showed, both in animals and humans, that the more viruses that are collected, the more apathetic the individual becomes. Vaccines are the best way to infect the body with viruses.

The aluminum from vaccines sequesters in the hippocampus of the brain, the seat of endocrine regulation and even dys regulated endocrine systems, and leads to behavioral changes.

I have seen plenty of behavioral changes following vaccination and will actually be speaking on this at a national veterinary convention next May. The sad thing is that this has been recognized for the past 150 years and there is still no consensus. I am sure this is due to the commercial protection of vaccines.

The American Veterinary Medical Association has been on record stating that the mammalian immune system [of pets] is not unlike the human immune system, and that viral vaccines (the only ones really worth the risk) are good for life once administered one time to a mature mammalian immune system.

Dr. Harris Coulter, author of Vaccination: The Rise of Criminality and Social Violence: The Assault on the American Brain, tracked the rise of vaccinations to the rise of social violence and criminality and also a drop in IQ. My book MARK OF THE BEAST, HIDDEN IN PLAIN SIGHT, updated the final chapter of Dr. Coulter’s book, “Medical Hubris and Its Unintended Consequences.” This violence, aggression, anger link to vaccines can easily be understood if even knowing about the common fevers and encephalitis that follows vaccinations, the high pitched cry and neurological disorders, the learning disabilities…..and these are obviously also occurring in animals although not admitted but very much recognized.

Those involved in training puppies and in the socialization of the dogs have linked the coincidence of behavioral changes in some dogs that follows the puppyhood series of vaccinations.

One thing I am POSITIVE about: if animal behaviorists are not thinking and understanding [the vaccination-behavior link], they are way off the mark in what they are understanding, recording, teaching and advising clients.

You should find one of the more highly attuned veterinary homeopaths to expand on this level of behavioral damage from vaccines issues. (From Jan: find a list of holistic veterinarians and vets trained in homeopathy here.  Homeopathy is your best chance to reduce the vaccine damage.)



Michael Dym, VDM, homeopathic veterinarian, on behavior changes after vaccination for rabies:
Unfortunately vaccination can result in certain sensitive individuals a chronic disease state one that is long-lasting, indeed in some cases a life-long condition…. This state of “vaccinosis” is understood as the disturbance of the life force that results in mental, emotional and physical changes induced by the laboratory modification of a viral disease to make a vaccination.

In other words, instead of seeing acute expressions of viral disease, we are instead seeing symptoms of chronic illness which are actually documented to occur in rabid animals. Symptoms of rabies include restlessness; viciousness; avoidance of company; unusual affection; desire to travel; inability to be restrained; self biting; strange cries and howls; inability to swallow resulting in gagging while eating/drinking; staring eyes; swallowing wood, stones, inedibles; destruction of blankets, clothing; convulsive seizures; throat spasms; increased sexual desires; disturbed heart function; excited and jerky breathing.

My biggest concern with pets are the changes in behavior after being vaccinated. This is usually along the lines of aggression, suspicion, unusual fears, etc. The essential aspect is a lack of control of impulses.

Many pets may exhibit any or many of the above behaviors indefinitely such as “reverse sneezing” and increased mounting seen in neutered pets. Conventional medicine does not explain these odd symptoms, but homeopathically these pets may be exhibiting symptoms of rabies vaccinosis and occur fairly commonly in my opinion.

You certainly need to follow the law with regard to rabies vaccination. A homeopathic remedy given at the time of immunization can help reduce side effects. If your pet is suffering from the above symptoms, he/she can be evaluated by a homeopathic vet to try and cure this chronic diseased state.


From Jan: Certain medications can also cause behavior changes. Research possible adverse reactions to medications  by searching on-line by product name, by reading the product’s package insert, by talking with your vet or by visiting the veterinary section of  Also check the label on your pet’s food, particularly dry food. Corn as a first ingredient, of several of the first 5 ingredients, may be influencing behavior. Switch to a better food.

Other articles you might find useful:

Rabies Vaccination: 13 Ways to Vaccinate More Safely
Protecting Dogs From Vaccine Reactions
Combination Shots for Dogs: Weapons of Over-Vaccination
Treating Adverse Vaccine Reactions by Jean Dodds, DVM
Vaccinating Dogs: 10 Steps to Eliminating Unnecessary Shots

Tags: aggression, behavior problems, dog behavior, dog training, drugs, fear, food, puppy, thyroid, Vaccination
Posted under Uncategorized, Vaccine Reactions | 12 Comments » Email This Post

12 Comments to “Is Your Dog’s Bad Behavior Caused by a Health Problem?”

  1. Carolyn in Belize Says:

    Very good article. Thanks too for the links — I am off to check out a drug prescribed for my dog. Always informative to visit your site. Thank you.

  2. Sirena Says:

    If my dog displays several of these behaviors/conditions, would that be enough to get an exemption (with a titer)?

  3. Chris Rabiyan Says:

    I am very interested in pursuing the link between vaccines and aggression, especially related to Fort Dodge vaccines. I recently had to put down my 10 month old puppy after he turned aggressive. The breeder is convinced that the aggression was a result of Fort Dodge issued by our vet (or possibly the anesthesia & sedatives used during his neuter surgery and an exploratory surgery for intestinal problems) and actually has a clause in the contract that voids the guarantee if Fort Dodge vaccines are given. Even though I advised the vet that I did not want Fort Dodge used, I have since learned that Fort Dodge is the only vaccines they use, and were in fact administered. Any additional postings & information would be appreciated.

  4. Jan Says:

    Chris, often, aggression caused by medication can be reversed. Unfortunately, few vets know how. Also know that you can vet shop in the future and find one who will use the brand you want. I suggest that the vaccine be thimerosol free. Merial’s vaccine has been recommended to me.

    Please make sure that you and your vet report the aggression reaction to the manufacturer and the USDA. That’s the only way things will change. See for more information.

  5. Jan Says:

    Hi Sirena. Whether or not a vet will consider a behavioral reaction to the rabies vaccine to be sufficient to ask for a medical exemption is up to your vet. It would have to be reported and put in your dog’s file. You will need a knowledgeable veterinarian. Re titers helping, they might help convince a vet, but there is no titer result that proves immunity in dogs. They currently use the human titer. It may reassure the vet but won’t change law. Support the study at to establish a titer standard for dogs. We’re just a year away from having one. And make sure your dogs reactions are reported.

  6. Blaire Bennett Says:

    I have a Maltese who is now almost 5. After her first rabies vaccine at 7 months there were some small changes in behavior that I thought were insignificant at the time and thought it was “little dog syndrome”. When she got her booster a year later she had a 180 degree turn in behavior. By the next morning she turned aggressive and bit me in the face.

    The next couple years became a long process of working with this. After the booster she didn’t get up for a week, I had to force her to drink and eat, she was completely lethargic when normally an extremely active puppy. I told all of this to my Vet but nothing was ever put in her file so I’m faced with a big problem now. As a puppy (pre-vaccine) she loved everyone, adults, children, and dogs. She only ever had a problem with large breeds. I now have an absolutley beautiful little girl that no one can approach and it breaks my heart. She will bite anyone that comes near her.

    I’ve tried talking to Vets and trainers along the way since this started, did a lot of research on the topic, but could not find anything that could help her. I have been considering going and doing blood work to make sure everything is in order as she has never had that done, but I’ve seen quite a few cases of thyroid issues and she doesn’t have any of the symptoms, nor does she have any other heath problems.

    So my question is to you is, in your opinion is there anything I can do to help her recover from this, or is it permanent? If you can point me in any direction of possible help I would be eternally greatful. It is so sad, like she doesn’t even understand a lot of her aggression. Sometimes she will wag her tail and get excited for someone to pet her, but I can’t let anyone because once they approach her she will snap. I would really appreciate any advise you can give me. Thank you, Blaire

  7. Jan Says:

    Blaire, please read my post What to Do When Your Dog Has a Vaccine Reaction There’s lots of information there that may help, including links to finding a vet who may be able to reverse the problems.

    Also, there are several good books on clicker training aggressive dogs. Check out There are several good books including “Click to Calm.” It is a kind way of dealing with aggression.

    Don’t give up. There’s an excellent chance that your dog can be helped.

  8. Reverse Sneezing: cause, duration & how to stop it | Says:

    […] After further research, I found that some vet’s believe that vaccines may be causing reverse sneezing as well as other behavior or health changes**. […]

  9. Gary Rokuta Says:

    I have a poor golden retriever that is only 1yr11mos old and already has allergies and I am sure from research from Dr. Ronald Schultz about overvaccinating can jeopardize their lives and cause allergies. I took her to 3 vets, the 3rd being a dermatology specialist that did blood work and after 3.5 wks., the results were environmental alergies. Meanwhile, I was giving her, (Brandy2), akc histoplex ab, moducare by Thorne Research, nature’s benadryl that’s called quercetin w / bromelein, among other supplements incl. omega3s, pet protandim, oil of oregano, colloidal silver and others. The immuno therapy pump droppers were started about almost 2 mos now and quite a bit of her hair came back but she has behavior issues and I get mad but I slways remember that it’s not her fault, it’s minds as I listened to that dsmn female vet that suggested ti vaccinate for distemper / parvo when I actually wanted to titer. I blamed her and she lied and also said that they aren’t sble to care for Brandy . What do u think as she is the academically inclined veterinary professional but I let her vaccinate and in a letter to me she said reactions from vaccines occur within 24 hrs. BS. THAT SHRINGE containing the vaccines had a lot, that looked like it was for a horse.

  10. Jan Says:

    Gary, your vet is lying, or is ignorant. If you like, I’ll send you a study of vaccine reactions happening within THREE days in 1.5 million dogs, published in the Journal of the American Veterinary Medical Association. Purdue vet school did the study.

    Also read and see if you dog even needed vaccinating in the first place. Probably not. If you ask for a titer to be run, that’s what you should give. And no dog with bad allergies should be vaccinated if titers are strong.

  11. Sheila Rimer Says:

    Jan – Sheila Rimer here! Met you long ago when you lived on Sailfish Point. Am so GLAD you are a lover of dogs. Surely the purest beings on this earth! I have Basset Hounds. Rescuing the older ones, these days – but I love them nearly more than my children. Well, at least as much! Was on line, just now, trying to find a copy of OUTCLASSING (successfully) for a friend I was telling all about you over drinks, last night! Would love to hear how you are, though the pics tell the tale! How could you be anything other than perfect as ever with those furbabies!

  12. dog behavior research Says:

    great post. thank you for sharing

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