Please read this article if you use a laser pointer as a toy:
> Scruffy is obsessed with shadows, lights, etc. Your description
> of your dog sounds just like Scruffy. She was originally raised
> with a little boy who used his laser toy when she was a young pup.
The behavior you both describe is obsessive-compulsive behavior, which in dogs is referred to as a stereotypy. This is the equivalent of a human with OCD washing his hands 100 times a day. It is a compulsively repetitive motor pattern over which the dog has no control. It is also called Canine Compulsive Disorder (CCD). Other examples of canine stereotypies include spinning (tail chasing), chewing on paws (Acral lick dermatisis), and appearing to snap at invisible flies in the air.
There is a chapter in Nicholas Dodman's book, The Dog Who Loved Too Much, called "Shadow of a Doubt," which tells the story of a dog that has the same disorder as the two dogs you have described. I have worked, as a trainer, with three dogs that had stereotypies, but not specifically with a shadow chaser like your dogs.
Robert is absolutely correct... You should have a veterinarian who has experience with stereotypies or a good canine behaviorist examine your dog as soon as you can. Behavioral treatments (training) usually have little effect on this type of disorder unless they are combined with medication. Anticonvulsants, mood stabilizing drugs such as Prozac (SSRI's) and/or tranquilizers are often prescribed to reduce the severity of shadow chasing and other stereotypies.
There have been a number of reports of shadow chasing stereotypy beginning after a laser pointer was used for training or playing with the dog, as Jane mentioned. Laser pointers or flashlights should never be used as training aids with dogs for this reason.
Although a stereotypy like this can increase in severity and can overshadow a dog's and owner's life, the good news is that what you have described is a well-known and identified disorder that usually responds to therapy with the types of drugs I mentioned.
Faye, what you heard is correct: Many specialists in this area,
including Dodman, believe that many stereotypies are the result of small seizures or convulsions that occur in the brain. This has been verified by doing a specialized type of EEG on dogs with these disorders. That may be why anticonvulsant medications seem to help many dogs. This disorder also tends to occur more in certain breeds, and both Labrodor and Golden Retrievers are among those breeds.
Although the medications, IMO, are almost always necessary to
really change the behavior, there are two things you can do that may have a positive affects.
First, ignore the dog when it does the light/shadow thing. Do not give it any attention because this may unintentionally reinforce the behavior.
Second, try to provide a varied and stimulating environment for the dog. Anxiety and boredom may increase the frequency of a stereotypy, so it is important to exercise the dog well, challenge it mentally with food toys, play, training, or whatever other activities seem to distract it from its obsessive behavior.
The stimulation and exercise by itself may make a difference in some dogs because it is unlikely that all CCD's are caused by convulsions. Zookeepers are well aware of the development of compulsive behaviors in zoo animals that are held captive without adequate stimulation or in environments that remain unchanged for long periods of time. Obsessive spinning has also been seen in dogs that were kept in small cages 24 hours a day at experimental facilities.
If you search the Internet for phrases such as "canine stereotypy" or "shadow chasing,"or "Canine Compulsive Disorder," you will find many articles on the subject. This should be thought of as a medical condition, so again, your first step should be to see a vet or behaviorist. The earlier the medical intervention, the better the dog's chances of recovering most fully.
This article is also informative on the subject.