Can depression cause memory loss?

Mental Health Expert Dr. Charles Raison Psychiatrist,
Emory University Medical School

Expert answer

Dear Laura,

The short answer to your question is yes. Yes, depression is frequently associated with memory problems, most likely because depression arises from abnormal functioning of brain areas that are also very important for memory. It's not uncommon for mild memory problems to persist for a while after people have otherwise responded to treatment and are doing better. As you intimate, medications also can adversely affect memory, especially in older people, but this is less likely in your husband's case because his memory has deteriorated without medication changes.

Having said all this, I've got to tell you that from the brief snippets of information you have provided I am worried about your husband. Sometimes doctors hear things with different ears than other people and worry about things that most people would pass off as unimportant. In the case of your story, I am struck by your comment that your husband can't remember how to get to places he's been to just a couple of days before. If he has always been bad with directions, and if the places you are talking about are hard to find, then it might be no big deal. But if you mean that he is uncharacteristically getting lost while driving places he should know well, then I am doubly concerned.

My worry stems from the fact that these types of gross memory lapses are not very characteristic for depression, either unipolar or bipolar, but are extremely worrisome in terms of potential dementia. While Alzheimer's disease seldom strikes before age 55 (and usually doesn't hit until a person is in his 70s or 80s), there is another type of dementia, called frontotemporal dementia that -- while rare -- strikes early in life. Tragically, 39 is not too young to worry about this condition.

Read one family's battle with frontotemporal dementia

As is always the case when I answer questions on this blog, I don't have enough information to offer any concrete diagnoses or treatment plans. But starting from what you have written, let me walk you through how I would think about the case. Let's assume, just for the sake of argument, that your husband is really having profound memory disturbances. The first thing I would want to know is when his symptoms started. If you told me that he has been having big mood swings since his late teens, with a few manias and lots of depressions, but was only diagnosed two years ago, I would relax a little, because this type of story makes it more likely that he really does have bipolar disorder.

If on the other hand, you told me that your husband was completely normal until a couple of years ago, at which time his behavior began to change, and with these changes came memory problems, I'd be very intent on ruling out frontotemporal dementia. The underlying principle here is that schizophrenia, bipolar disorder and the other severe psychiatric conditions tend to start early in life and are usually chronic. On the other hand, the older a person gets the more likely it is that changes in emotions, behavior and thinking are the result of a clear organic illness that has been missed.

For example, at least half of all people who have a first manic episode after the age of 60 have a clearly findable disease that is driving the symptoms. On the other hand, the chance that a first manic episode occurring at age 18 will be due to a clearly definable medical/neurological condition in an otherwise apparently healthy person is about 1 in 100. While it is not unheard of for bipolar disorder to manifest out of the blue at age 37, it would be unusual enough that I would want to make sure nothing clearly medical or neurological was going on.

Let me conclude with a few comments about frontotemporal dementia. Unlike Alzheimer's disease which tends to start at the back of the brain and affect higher cognitive processes first (like memory, speech, task planning), frontotemporal dementia -- as the name suggests -- starts in the front parts of the brain. These areas of the brain are directly involved in many aspects of what we call personality, such as the ability to manage impulses, control our temper, or have a wide range of appropriate feelings. Not surprisingly, when these parts of the brain begin to die in frontotemporal dementia, these are the areas where the troubles start.

Frontotemporal dementia is often mistaken for a psychiatric disease, because anger, impulsivity and depression are common early symptoms. People begin to demonstrate poor judgment, and begin to show the types of memory problems that your husband may be suffering. A final striking feature of the disorder is that the person is typically oblivious to the changes in themselves that are glaringly obvious to everyone else. Also, certain psychiatric conditions often are associated with lack of insight, but depression does not tend to be one of these. So if your husband is clueless about his own condition I'd be truly worried.

If any of this sounds like your husband, you might want to take him to a neurologist and ask about getting a work-up for frontotemporal dementia. I hope it does not sound like your husband, and that I have read your question with an exaggerated eye.