More than sad: Depression affects your ability to think

James Cartreine, PhD

Contributing Editor

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When you think of clinical depression, you probably think of feeling sad and down for long periods of time; losing your energy and your interest in things you used to enjoy; sleeping too much or too little, or eating too much or too little. But besides these, depression can actually change your ability to think. It can impair your attention and memory, as well as your information processing and decision-making skills. It can also lower your cognitive flexibility (the ability to adapt your goals and strategies to changing situations) and executive functioning (the ability to take all the steps to get something done).

For people with severe depression, medications can provide some relief of low mood and energy, bolster the motivation to engage in enjoyable and important activities, and help people return to normal sleeping and eating patterns. (Notably, antidepressants are less helpful in general for mild and moderate depression.)

But we don’t know whether antidepressant medications treat cognitive impairment related to depression. Recently, an international research team attempted to answer this question as part of a larger study on depression treatment. Their results were published in The Lancet last month.

To study the effect of three common antidepressant medications on depression-related cognitive impairment, the researchers asked over 1,000 people with depression who were taking either escitalopram (Lexapro), sertraline (Zoloft), or venlafaxine-XR (Effexor-XR) to go through extensive cognitive testing. In short, none of the medications helped. Of these patients, 95% showed no improvement on any of the cognitive impairments mentioned above, and none of the three drugs was better than the others at improving cognitive symptoms.

This result is not completely surprising — antidepressant medications are mainly meant to help improve mood and increase the ability to participate in beneficial and enjoyable activities, two key aspects of depression treatment. It’s also worth noting that different parts and processes of the brain are responsible for cognitive (versus emotional) functioning; this may explain why the three drugs tested didn’t seem to help improve cognitive symptoms. New drugs for depression may be able to address these symptoms as well.

Beyond medications, problem-solving treatment can train people how to improve their problem-solving skills, and cognitive behavioral therapy can teach people to recognize and challenge distorted thinking patterns. Another approach, cognitive remediation therapy, uses practice drills to improve memory and executive functioning. Combining these behavioral interventions with antidepressants may yield better results for improving depression-related cognitive impairments.

There are some limitations to this study: it’s not known if the participants had cognitive impairments before they developed depression, and the length of drug treatment and follow-up was short — eight weeks in total. However, this study is important because the cognitive impairment symptoms of depression have received little attention — and haven’t necessarily been the target of medications for depression. It shows that we have a long way to go in helping people with depression return to a normal level of full mental functioning.

Related Information: Understanding Depression


  1. kym berlin

    Great article. I learned a lot from the info ! Does someone know if I could acquire a blank CA SC-100 copy to type on ?

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  3. aboiyad3d

    It’s like a rollercoaster, you feel the wave coming on, realize you’ll eventually come out of it thank you for sharing

  4. Andrew Verrijdt

    This may help to explain why stimulants like Modafinil have had some efficacy in treating depression.

    The drug has been shown to boost cognitive ability somewhat (although these effects have been exaggerated beyond reason by the drug’s ‘trendiness’) so it makes sense that it could help to overcome some of the cognitive deficits caused by depression.

    Very interesting.

    -Andrew Verrijdt

  5. Elise

    Amen to previous post. It’s like a rollercoaster, you feel the wave coming on, realize you’ll eventually come out of it, so HOLD ON for the ride!
    (Sticking with Paxil and talk therapy)

  6. Tom Wootton

    Those of us who understand how to function during depressive episodes find advantages in the way our minds work. It is too bad studies only focus on those who have not yet learned how to use depressive states. The primary limitation of the study is they only study people with no ability to function during episodes. You would conclude that cars have no utility too if you only studied people who cannot drive.

    The secondary problem with the study is the assumption that the only way to solve the first problem is to use tools only designed to make depression go away. While tools to lower the intensity of states outside of one’s comfort zone are an important part of moving toward functionality during states, such tools alone will never get someone to full functionality during future episodes. I am happy to share the tools needed if you are interested.

    The tertiary issue is basing success on memory and attention for irrelevant (to the state) topics. If you ask a skilled depressive to recall details from previous depressions you will find their memories are enhanced. You will also find skilled depressives have enhanced decision-making abilities during states. Nonetheless, if you tested a trained depressive even with the mistaken cognitive measurements you will find much less dysfunction than you find with the untrained subjects in the study. You will even find that some of us are better at those skills during depressive states.

    But testing a depressive for such skills is like testing a car driver’s ability to walk. They are not the primary advantages of depression. If you test for empathy, compassion or meaning-of-life issues you will find trained depressives are way ahead of everyone in those skills. If you want to truly understand depression you need to start learning from those of us who know how to function during it.

    • Jerry

      Tom, I find your thoughts and experience with depression most enlightening. I have a family member that has suffered with Bipolar
      disease for decades. During his manic phases, he was extremely
      successful with one restaurant after another.

      Sadly, during these phases, he was medicating with alcohol and cocaine.
      The domino effect enabled his demise. Along the way, he not only
      hurt himself, but his family as well. Erratic thinking and behavior had
      unfortunately put him in tenuous legal positions.

      To this day, I don’t understand why it took so long for a clinician to diagnose
      his condition and to provide him with a proper treatment plan.
      Fortunately, the last five or so years have been a turn around story for
      him due to the proper therapist and medication.

      As one who “gets it”, I would appreciate learning more about the tools
      that you mentioned in your post. Your insight would be most welcome.
      Also, congratulations for learning and understanding how to manage
      your depression.

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