This is a touchy subject, and for good reason. There is a lot of stigma around behavioral medication for people and dogs. Medication is seen as a band-aid and overused. As someone who suffers from PTSD, I had a period of about a year where I personally took prescription medication (Ativan as needed for anxiety, and Lexapro for depression) after a car accident. I've also had a dog who warranted being on medication for fear and aggression. It took me 3 years to come around to the idea, and those 3 years were VERY difficult, even with me as a professional trainer. I finally sought the opinion of a board-certified veterinary behaviorist, who immediately said my dog should be on medication. I finally acquiesced, and that medication gave us 2 more years together, and they were the best years.
How do they work? Prozac (or the generic Fluoxetine) is an anti-depressant in people, and can also help dogs suffering with fear and anxiety. The aggressive symptoms they display become less intense or go away entirely. The disadvantage is this medication has a loading period of a few weeks to get into the dog's system, and playing with the dose is necessary to find the magic. Dogs on the right dose do not act like zombies or seem in any way "drugged up." They are simply benefitting from the medication and doing better. Prozac requires a weaning off period to avoid withdrawal. Trazadone helps with fear and anxiety as well, and has a mild calming effect at the right dose. The advantage is it is fast acting and there is no withdrawal to consider. The disadvantage is the calming effect and that it is situational, you must keep giving the dog the medication for the effects to be seen, it does not build up in their system like Prozac does.
I'm never trying to "load your dog up with drugs." If a dog warrants being on such medication as Prozac or Trazadone, the goal is ALWAYS to wean them off after the medication has had time to provide its service. That period can be between 6 months and a year or so. Sometimes, it's purely a chemical imbalance causing the behavioral symptoms, and during the weaning off process, it is determined that the dog should remain on the medication indefinitely. However, that is not the goal, my intention, or what usually happens. The medication is a tool, just like a training harness. The goal is always to wean off tools as the dog's training progresses and improves.
Generally speaking, these dogs don't have a particular traumatic event causing their fear and aggression. I usually try to tackle just that trauma without medication. These dogs were bred by irresponsible breeders who didn't consider temperament enough before having a litter of adorable puppies and selling them to unsuspecting owners or surrendering them for adoption. However, even responsible breeders who do everything right can have an off puppy in a litter of otherwise happy-go-lucky, normal puppies. When I take a history and determine the owner has owned the dog their entire life, from puppyhood, and done everything "right" but the dog is still extremely upset, no amount of training the world can fix genetics and brain chemistry. Besides genetics, prolonged stress can also alter brain chemistry, creating neural pathways that prohibit stress management and increase anxiety and/or aggression. If your dog is 2 years old or older, has always "been like this," and is constantly in distress, that's a huge red flag for poor brain chemistry. It takes a very severe case for me to recommend medication for dogs under 2 years old. Puppies are developing physically and emotionally, going through various phases -- so I prefer to wait.
Medication as part of a Behavior Modification Plan will help the adjust chemicals in the dog's brain that control stress and make everything easier. The dog's quality of life improves because they're not so upset by their triggers, and training will progress exponentially faster because the dog has a better frame of mind from which to learn. I will be an advocate for the dog and recommend medication if I deem it advantageous to our plan.
Having just been informed someone thought I was "a piece of sh*t trainer" for recommending their dog try behavioral medication (Fluoxetine, the generic for Prozac), I wanted to outline my personal criteria for recommending a prescription for medication from your vet in case it can help someone else in future:
I will ALWAYS respect the wishes of the owner. There is no judgment either way the owner decides. If you decline medication, that is your right. If I believe it possible to do safely, we may continue on with training as best we can. If I feel very strongly the dog should be on medication for safety reasons, I will terminate the training relationship. I don't report owners as neglectful to animal control for declining behavioral medications. This is a very personal decision, but my priority is 100% the quality of life for the dog.
When I recommend medication, you can get that medication from your veterinarian or a veterinary behaviorist. I am not a doctor, so I cannot prescribe medication. It is then the responsibility of the veterinarian to also determine the dog warrants medication. I have yet to have a veterinarian turn down a client after I make the recommendation. Note: this means that 100% of clients who followed my recommendation to seek medication for their dog have been approved by their veterinarian. However, there are veterinarians who don't like to prescribe these medications and refuse to even entertain the idea -- you can go to another vet and ask for a second opinion.