Can mental health problems and stress affect your memory?

It's a familiar situation: you rush out of your house feeling stressed, only to realise you've left your wallet at home. Or you start to panic during an exam or interview, and find your mind going blank. If you've ever been accused of being scatty or distracted, you'll be all too aware of the ways stress can affect your memory.

As the COVID-19 pandemic lingers on, chances are we're all feeling the strain. And while stress and anxiety can affect our functioning in many different ways, memory issues are an important piece of the puzzle. Whether you've been experiencing complete blanks in your memory - or are simply feeling preoccupied and repeatedly misplacing your keys - it could be due to shaky mental health.

How stress affects short-term memory

"Having memory problems is quite a common experience when we are very stressed, anxious or depressed," says psychiatrist Dr Karen Graham. "It can be harder to focus, think clearly, and learn new information. When we're preoccupied about a stressful issue or have a busy worrying mind, then we're distracted instead of being fully attentive. Depression can also make it difficult to focus well on what we're doing."

She adds that many mental health issues can impact our quality of sleep, resulting in reduced alertness throughout the day. It means information is less likely to get encoded properly as 'working memory' - the part of the memory system that's involved with day-to-day tasks. Short-term memory, then, is often the first thing to suffer at times of ongoing stress and anxiety.

The effects on long-term memory

However, since short-term memory is necessary to develop longer-term memories, there can also be issues with learning and studying. And if stress becomes chronic, it can affect both the way information is laid down and the way it is recalled.

"When anxiety is very high, it interferes with new learning and therefore subsequent recall," says Dr Levent Yurdakul, consultant clinical psychologist at Clinical Partners. "The body produces the hormone adrenaline, which mobilises the body for an impending threat and leads to a state of hypervigilance. This means we are scanning the environment for potential signs of danger and unable to focus on other stimuli around us."

This is why your memory might be hazy if you've been through a shock or trauma - your capacity to take in information was overwhelmed. In some cases, trauma can lead to inexplicable memory blanks, particularly if the stressful events occurred in childhood.

"Often clients with difficulties in early childhood describe sketchy recall of events and details. This is most likely due to the effects of heightened anxiety disrupting memory processes," says Dr Yurdakul. "Where there is significant disturbance in memory or behaviour, which is most likely to be associated with PTSD or a significant trauma, it is important to seek professional help to establish the likely cause of the memory impairment."

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A complicated relationship

There is another factor in the mix too, which is that memories can change after they’re formed, depending on how we're feeling at the time and other contextual factors. 'False memories' - in which you remember something that never happened - are a surprisingly common phenomenon.

"Even after long-term memories have been formed, our current state of mind can affect old memories when we retrieve them," says Dr Graham. "What all this means is that memory is malleable, not fully reliable, and very dependent on the mental state we are in."

In other words, stress and memory are intimately connected, albeit in complicated ways. One 2017 review paper, which looked at 113 studies on stress and memory, came up with a few interesting findings:

• Stress impairs memory unless the material being learned is directly related to the stressor. In these cases, stress actually improves memory formation.

• While stress increases the hormone cortisol, the amount of cortisol released isn't directly related to the effects of stress on memory.

• Women on oral contraceptives are less likely to experience stress-related memory impairments.

How to alleviate the problem

However, it isn't necessary to tease out all the nuances of stress and memory to realise that too much stress is bad for the system. Dr Yurdakul says, if you're feeling forgetful, it may help to strive for better emotional regulation.

"Strategies such as meditation, t'ai chi and mindfulness can help reverse the effects of stress and promote a state of relaxation" he says. "Regular engagement in such activities helps form adaptive behaviours that become habitual and build resilience when dealing with stress. Regular exercise or finding fulfilling hobbies can also be very important in promoting enjoyment of life and emotional well-being."

He adds that how we appraise events is also very important. If we interpret an event as threatening, we'll experience a physical stress response. However, it's in our power to reframe how we see things.

"Sometimes it is possible to do this on our own, sometimes with a trusted friend or a relative. Sometimes it may be necessary to see a psychologist or psychotherapist who practises therapies such as CBT or IPT (interpersonal therapy)," he says. "Making good use of one's support network is a pivotal strategy for good mental health."

There are also self-help books that can be invaluable as we move through this process. Dr Graham has written two books, Accept How You Feel and Mind What You Think, which shed light on the underlying patterns behind stress and anxiety.

When to seek help

If you think there's something else going on - and your memory problems are more serious and persistent - it may be time for a medical check-up.

"Memory problems can also be caused by an underactive thyroid gland, drinking too much alcohol, medication side-effects, vitamin B12 deficiency etc, and these can be addressed," says Dr Graham. "They have other symptoms or clinical signs, to differentiate them from memory problems due to mental health."

Of course, this is not to imply that mental health issues are somehow less serious than physical ones. If stress, anxiety or depression is the culprit - common at a time of COVID-19 - then getting help for this should improve your memory too.