Everyday stress won't affect hair growth or lead to hair loss, but extreme stress can limit or even halt the growth of hair.
You don't have to be so stressed that you're literally tearing out your hair to experience hair loss. Stress changes your biochemistry and can lead to a range of health conditions, from insomnia to serious cardiovascular problems.
Your hair is not immune to stress. Though acute, fleeting stress—such as the annoyance of an academic exam or a few weeks of extra pressure at work—is unlikely to trigger hair loss, chronic stress can and does undermine hair health.
Mental Health Conditions That Cause Hair Loss
Stress can overwhelm even the most stable minds, and some of the ways we cope with stress are profoundly damaging. Witness compulsive drinking, gambling, and spending—all of which help in the moment but cause lasting harm. Some people manage stress by developing compulsive behaviours. Obsessive-compulsive disorder and related conditions can cause detrimental habits such as twirling the hair, obsessive hair-washing, and even sucking on the hair. Over time, bad habits damage the hair shaft. They won't cause your hair to fall out, but they can damage your hair so much that it looks much thinner.
Another stress-related condition, trichotillomania, causes sufferers to pull their hair out. Some people pull brows or eyelashes, but plucking head hair is also common. This can cause temporary baldness. Left untreated, trichotillomania can severely damage hair follicles, potentially causing lasting baldness even after the condition is treated. If you can't stop pulling your hair, your hair's health depends on seeking prompt mental health treatment.