Smoking and Mental Health: The Real Relationship Between Cigarettes and Mood

People with mental health conditions smoke at much higher rates than the general population. A meta-analysis of 42 studies across 20 countries found people with schizophrenia were about six times as likely to smoke as the general population (OR 5.9). Smoking is also more common among people with depression and anxiety.

The common belief is that people smoke to self-medicate. The evidence points somewhere more useful: quitting doesn't make mental health worse, and on average it makes it better.

The Anxiety Paradox

Many smokers feel a cigarette calms them. Part of that calm is relief from the tension of going without one — the withdrawal that builds between cigarettes. The NHS puts it plainly: you may think smoking helps you relax and deal with stress and anxiety — in fact, the opposite is true.

The evidence after quitting fits that picture. In a study of 101 dependent smokers who stayed completely stopped, anxiety did not rise after quitting — it fell from the first week. The authors suggest the anxiety other studies recorded may come from lapses rather than from quitting itself.

Smoking and Depression

Low mood is one of the core withdrawal symptoms, so a dip in the first weeks is common. Over the longer term, the Cochrane review of 102 studies found depression symptoms lower after quitting than with continued smoking, with the same improvement seen in people diagnosed with mental health conditions.

A caution: in a study of people quitting on their own, low mood after quitting predicted going back to smoking. If you have a history of depression, tell your GP you're quitting so your mood can be watched, and get help straight away if you have thoughts of harming yourself.

Smoking and Schizophrenia

Smoking rates are especially high in schizophrenia. Explanations researchers have proposed include nicotine's short-term effects on attention and shared genetic factors; none is settled.

An important medicine interaction: tobacco smoke speeds up the liver enzyme (CYP1A2) that clears several antipsychotics, including clozapine and olanzapine. After quitting, blood levels can rise, and doses may need reducing. Anyone on these medicines should quit with their psychiatrist or GP involved, not alone.

ADHD and PTSD

Smoking is also more common among people with ADHD and among trauma survivors. We didn't find reliable figures to quote. If you have either condition, the same principles apply: quitting with medication and support, and keeping your mental-health team informed.

What Happens to Mental Health After Quitting

The Cochrane review of 102 studies and more than 169,500 people concluded that mental health does not worsen as a result of quitting, and that quitting is associated with small to moderate improvements in anxiety, depression and mixed anxiety-and-depression symptoms — in the general population and in people with mental health conditions. An earlier review of 26 studies found the size of the improvement equal to or larger than antidepressant treatment for mood and anxiety disorders. The NHS says it can take as little as 6 weeks to start feeling the mental health benefits.

The certainty ranges from very low to moderate, because these are observational studies. But the direction is consistent.

Stop-smoking medicines and mental health: the EAGLES trial of 8,144 smokers, about half with a psychiatric history, found no significant increase in moderate or severe neuropsychiatric side effects from varenicline or bupropion compared with nicotine patches or placebo. The US FDA removed its boxed warning in 2016 while noting the risk "is still present, especially in those currently being treated for mental illnesses" — so tell your doctor about your mental health, and seek help at once if your mood or behaviour changes.

FAQ

Does smoking help with anxiety and depression?

It can feel that way, because a cigarette relieves the tension of going without one. But the Cochrane review found anxiety and depression symptoms lower after quitting than with continued smoking, and the NHS says the opposite of "smoking helps you relax" is true.

Why do people with mental illness smoke more?

The reasons aren't settled. Researchers point to short-term effects of nicotine on attention and mood, shared genetic factors, and the fact that the tension between cigarettes feels like anxiety. Whatever the cause, quitting improves mental health on average in people with mental health conditions too.

Is it safe to quit smoking if you have depression?

Yes, with support. Low mood can dip during withdrawal, and low mood after quitting predicted relapse in one study, so tell your GP you're quitting. Varenicline, bupropion and NRT can all be used — the EAGLES trial found no significant increase in serious mental-health side effects — but your doctor should know your history. If you take clozapine, olanzapine or similar medicines, doses may need adjusting once you stop.