If you or a loved one is experiencing memory loss, it's important to see your doctor. While there's a chance it may be dementia, particularly if you're over the age of 65, it's worth remembering that many things can cause forgetfulness. In fact, more than 50% of patients referred to memory clinics are not diagnosed with dementia, according to neurologists at the University of Sheffield.
See also: Eight hidden signs of dementia
See also: Middle-aged 'should curb booze to avoid dementia
1. You've been stressed lately
Several studies have found a link between chronic stress and short-term memory loss. Researchers at Ohio State University found that mice who were exposed to prolonged stress – in the form of an aggressive intruder mouse – had a hard time recalling where the escape hole was in a maze they'd previously mastered.
The bullied rodents also experienced significant brain changes, including inflammation caused by the immune system's response to stress. Thankfully, the mice made a full recovery after four weeks.
2. You're going through the menopause
The menopause doesn't just cause hot flushes and night sweats. Fluctuating hormone levels cause memory problems for 60% of menopausal women, according to researchers at the University of California.
And forgetfulness appears to be most acute during the early period of post menopause, 12 months immediately following a woman's last period, say researchers at the University of Rochester Medical Center.
"Women going through menopausal transition have long complained of cognitive difficulties such as keeping track of information and struggling with mental tasks that would have otherwise been routine," said neuropsychologist and lead researcher Miriam Weber, Ph.D.
Thankfully, the effect appears to be temporary and memory skills return to normal in the years following the menopause. "The most important thing that women need to be reassured of is that these problems, while frustrating, are normal and, in all likelihood, temporary," adds Dr Weber.
3. You're not sleeping well
Chronic insomnia is known to have a major impact on memory, but you might be surprised to know that just one poor night's sleep can cause forgetfulness and even lead to false memories.
Researchers at Michigan State University and the University of California, Irvine, showed volunteers photos of a simulated burglary, then asked them to remember the details the next day. Those who hadn't slept for 24 hours – and even those who'd had five hours of sleep – were more likely to mix up event details than participants who were well rested.
The conclusion? "People who repeatedly get low amounts of sleep every night could be more prone in the long run to develop these forms of memory distortion," says the study's co-author Dr Kimberly Fenn. "It's not just a full night of sleep deprivation that puts them at risk."
4. You're getting too much sleep
Conversely, getting too much sleep can also have a negative impact on your memory. Researchers at Harvard found that women who slept for nine hours or more on average performed just as badly in cognitive tests as those who slept for less than five hours.
"Our findings suggest that getting an 'average' amount of sleep, seven hours per day, may help maintain memory in later life," says study leader Elizabeth Devore.
The researchers estimated that under-sleepers and over-sleepers were mentally two years older than the women who got seven to eight hours of shut-eye a night.
5. Your diet is unhealthy
Experts have long known of a link between diet and cognitive functioning. Unsurprisingly, foods that are high in fat and sugar have a negative effect on memory. According to researchers at the University of California, such foods reduce levels of a natural brain chemical, called BDNF, which is crucial for learning and memory performance.
Conversely, studies show that eating a diet rich in omega-3 fatty acids – found in oily fish, walnuts and flax seeds, helps to improve brain functioning.
6. You're not drinking enough water
Even slight dehydration can impair our ability to think clearly, control our mood, and recall facts, according to a study by the University of Connecticut. Sip water regularly throughout the day, even if you don't feel thirsty (thirst only occurs once your body is one to per cent dehydrated) and drink at least eight glasses a day.
7. You need to lose weight
In case you need another reason to go on a diet, it turns out that carrying excess weight can impair your memory. Researchers at Cambridge University tested the memory of adults aged 18-35 and found that those with an overweight or obese BMI scored poorly compared to those with a healthy BMI.
Overweight volunteers performed significantly worse because of an impaired ability to form coherent and vivid memories, say researchers. This is in keeping with earlier studies which show that obesity has a significant impact on brain structure and function and can cause shrinkage in certain parts of the brain, including the hippocampus which is critical for memory formation.