Is Your Cat Making You Crazy?

Is Your Cat Making You Crazy?

Pop Quiz: What do cats have in common with the following?

  • Alzheimer’s disease
  • Anxiety
  • Bipolar disorder
  • Depression
  • Impulsive behavior
  • Schizophrenia
  • Suicidal thoughts

Answer: Toxoplasma gondii

Did you know that more than 40 million Americans may be infected by this tiny single-celled parasite that is often carried in cats and shed in their feces? The parasite infects many animals, but it can only sexually reproduce in cats. When it infects a rat—or a mouse or a bird or some other small creature—it releases an enzyme to boost the feel-good neurotransmitter dopamine, which is involved in risk-taking, reward, and motivation.

Scientists believe it effectively rewires the brain, so the rat gets hooked on cat urine and basically turns into a cat-seeking missile. Instead of instinctively fearing and running away from cats, the rat runs toward their natural predator. Not surprisingly, the cat eats the rat. And then the T. gondii starts to reproduce at an alarming rate.

In an amazing TED talk, science writer Ed Young recounts this most unusual love story and calls it a classic tale of “Eat, Prey, Love.”

The story doesn’t end there.

Toxoplasmosis and Mental Illness

When an unsuspecting human empties the cat litter box and comes in contact with the parasite, they can become infected. The T. gondii shed in feline feces can also seep into our water and into the ground, where it can be picked up by humans. This infection, called toxoplasmosis, has a strong association with a wide range of neuropsychiatric symptoms.

  • Schizophrenia: Over 100 studies have found a correlation between this common infection and schizophrenia, but they have yet to prove that it causes schizophrenia and other psychotic disorders.
  • Bipolar disorder: In the medical journal Pathogens, researchers suggested T. gondii might be a trigger for bipolar disorder.
  • Anxiety and depression: The infection is also associated with generalized anxiety disorder and depressive symptoms, according to the Journal of Affective Disorders.
  • Impulsivity: Considering this infection causes rats to act more impulsively and take greater risks, it’s suggested that it can lead to similar behaviors in infected humans. For example, a pair of studies from 2006 and 2002 indicated that toxoplasmosis is associated with a greater risk of traffic accidents due to increased risk-taking.
  • Suicidal thoughts and behavior:  A 2018 study on 155 psychiatric patients who had attempted suicide and 135 healthy people found that those who had tried to take their own lives were more likely to be infected with toxoplasmosis.
  • Alzheimer’s disease: Toxoplasmosis has also been linked to memory issues and Alzheimer’s disease, Parkinson’s disease, autoimmune disorders, cancer, and heart disease, according to a 2013 review.

In addition, if a pregnant woman becomes infected, she can pass the infection to her developing fetus, which can lead to brain damage or blindness at birth, or mental disabilities later in life.

The parasite is controlling the host. It makes you think that maybe we don’t have as much control over our behavior as we think we do.

Testing for T. Gondii

If you’re experiencing mental health issues—such as schizophrenia, psychosis, anxiety, depression, or memory problems—and you aren’t seeing improvement from standard treatment, it’s worth investigating if an underlying infection like toxoplasmosis is involved. Brain imaging and screening tests can help detect infectious diseases and get an accurate diagnosis so you can get the proper treatment.

At Amen Clinics, when we see evidence of infections on brain SPECT imaging scans, we do additional lab work and testing. Our integrative medicine physicians are trained to diagnose and treat any infections, such as T. gondii, Lyme disease, Epstein-Barr virus, H. pylori, and others.

If you want to join the thousands of people who have already visited Amen Clinics and enhanced their brain function with our personalized diagnosis and treatment plans, speak to a specialist today at 888-288-9834. If all our specialists are busy helping others, you can also schedule a time to talk.


  1. I am REALLY disappointed in this article. As a well-respected physician, Dr. Amen is well versed in scientific methods and research. People are MUCH more commonly infected with toxoplasma due to eating raw or undercooked meat and not washing fruits and vegetables. Rather than immediately blaming the family cat, emphasis should instead be placed on paying attention to food safety.

    Comment by Kris — June 22, 2020 @ 5:17 AM

  2. My cat, being strictly indoors, doesn’t have much opportunity to interact with rats (or other vermin), but I feel we need to present the WHOLE story, not the PG 13 version (which isn’t helpful to us, as medical professionals). What are the statistics on strictly indoor cats contracting or having toxoplasmosis? And can their stool be tested?

    Comment by Christine Marucci Magidin — June 23, 2020 @ 6:50 AM

  3. This is enough reason not to own a cat. The last posted question deserves an answer. My cat, being strictly indoors, doesn’t have much opportunity to interact with rats (or other vermin), but I feel we need to present the WHOLE story, not the PG 13 version (which isn’t helpful to us, as medical professionals). What are the statistics on strictly indoor cats contracting or having toxoplasmosis? And can their stool be tested? an answer. I would like an answer.

    Comment by Sharon M Robbins — June 24, 2020 @ 2:52 AM

  4. With all due respect Dr. Amen, the marketing of your products and services have led to more of a “sales pitch” infomercial style instead of providing thorough, complete information. I have been following your work for maybe 15 years, having purchased a CD set once upon a time, that helped me more than it did my ADHD husband. As of late, I have been noticing a distinctive change as the “Marketeers” have taken over so many narratives within the health communities. It’s my sincere hope that the current “Info-Wars” hidden in the algorithmic programing doesn’t lead us to holding marketing firms like Facebook, Google, etc. as the next demi-gods, profiteering within the health and science communities for BIGGER monied agendas only. Instead of true public health through open, honest, REAL science, NOT funded by Big Pharma’s greed and censorship with partial information for product marketing purposes only, is the next hurdle of consumer protection our overstimulated fear receptors require protection from. I pray, you are truly one of the “good” guys………The “Mad Men” seem to have gotten even crazier and more overtly, obsessively controlling in our consumerized, mesmerized evolving societal structures. Aho!

    Comment by Mary Blazine — June 24, 2020 @ 3:06 AM

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