Serotonin plays an important role in the neuro-chemical control of aggression in the brain, especially when a component of impulsivity is present.  Several dogs have shown that there serotonin levels are not the same as normal dogs.  This condition is similar to conditions like clinical depression, obsessive compulsive disorders, etc., in humans.  Norepinephrine, dopamine and gamma-aminobutyric (GABA) are other neurotransmitters in the brain that can be involved in anxiety, mood regulation and cognitive function.  Neurotransmitter often work together and have an affect on each other.  Some neurotransmitters replenish more quickly that others. Experiences, stress and diet are some of the things that can affect neurotransmitter levels.

How do I know?

Dogs who become aggressive as a result of a chemistry imbalance in the brain also have a learned component to the aggression so it can be challenging to diagnose unless you are a veterinary behaviorist.  A veterinary behaviorist will take a detailed history from you and will look for other behaviors that may be out of the ordinary.

For example, some dogs who demonstrate a generalized anxiety disorder may find it hard to relax at any time in a new environment, even when he or she has been there for some time.  They may continue to pace, or if they lie down, they may not fully settle.  There heads may stay upright, or their limbs may still be tightly pulled into the body.  Other dogs won’t explore a new environment at all, instead preferring to stay close to their owner.  There are many other indications that the aggression problem maybe a result of a brain chemistry imbalance.  A veterinary behaviorist is trained to understand and recognize what behavior is typical for a normal healthy dog and what is not.

How is it treated?

As with humans, there are a number of medications that will help behavior modification depending on the dog.  The family of SSRI drugs, medications such as Prozac or Zoloft have had the most success in combination with “therapy” i.e. behavior modification techniques in treating aggression for those dogs who need it. Regardless of brain chemistry, there are not many behavior cases which will respond to medication alone due to the learning component involved.

Learn more about medications prescribed for dog aggression.