Smoking and depression: Is there a link?

Depression is a mental health condition that can affect mood, thoughts, and behavior. It has been found that many people with depression are smokers, prompting the question of whether there is a link between depression and smoking, and whether one can cause or contribute to the other.

Can smoking cause depression?

There is a great deal of research investigating the link between depression and smoking but currently, this link is not entirely clear. Many studies show that people with depression are much more likely to smoke than those without, while there is also research to suggest that people who smoke are more likely to develop depression ^[1][2].

As such, there is certainly a link between the two, albeit complex and not fully understood. It is unclear whether smoking can cause depression, but it may increase the likelihood for some individuals, particularly those who have other genetic and environmental risk factors of the condition ^[1][3].

Smoking has been found to have an impact on brain function and the way in which certain chemicals are produced and utilized, thereby having an impact on stress responses and mood, suggesting that it may worsen or prolong symptoms of depression ^[2][4].

Can quitting smoking cause depression?

Quitting smoking cannot cause depression, but it may trigger a depressive episode in someone with major depressive disorder or temporarily worsen ongoing symptoms. This is likely due to withdrawal symptoms caused by smoking cessation, that can contribute to an increase in symptoms of anxiety and depression ^[3][5].

Smokers are likely to experience cravings and withdrawal symptoms after not smoking for a period of time, which can cause irritability and low mood. However, these symptoms are found to be alleviated after around 3 weeks of cessation, following which there is a long-term improvement in mood ^[6].

People with depression may experience more severe withdrawal symptoms than those without, so they may find it more difficult to quit smoking, but those who maintain cessation will experience a positive effect on their mood ^[5].

Studies have found that people who quit smoking experience an improvement in quality of life and mood, compared to those who continue smoking, an outcome which may even be more effective than antidepressant medications. As such, quitting smoking can actually reduce depressive symptoms, and can help in reducing or stopping the use of antidepressant medication ^[4][6].

How does smoking affect the brain?

When smoking, nicotine reaches the brain in a matter of seconds and can initially contribute to a feeling of relaxation and decreased stress. When someone continues to smoke, in an attempt to keep feeling these improvements in mood, their brain experiences a prolonged exposure to nicotine, causing several chemical changes in the brain, which leads to withdrawal symptoms and cravings when a person tries to stop smoking or goes a few hours without smoking^[5].

Research shows that, when the brain is exposed to nicotine for extended periods, there is an increased risk of dysregulation in certain chemicals, including neurotransmitters related to mood such as serotonin and dopamine, and hormones related to stress such as cortisol. This change in activity in the brain then contributes to a worsening of mental health symptoms ^[1].

Because of this, someone who is dependent on cigarettes will often experience feelings of irritability, stress, and depressed mood if they haven’t smoked for some time, thereby causing them to want a cigarette to alleviate these symptoms. This is why people consider smoking to be relaxing, as it can cause a temporary relief from the symptoms that are brought on by cravings ^[4].

However, withdrawal symptoms do not occur in those without a dependency on nicotine, so non-smokers do not experience this exacerbation of underlying anxiety or depression symptoms. The perceived relief from symptoms of anxiety and depression caused by smoking is only temporary, does not deal with the underlying cause of the condition, and potentially worsens symptoms ^[3][4].

It has been found that withdrawal symptoms last for around three weeks, so it is thought that if someone can refrain from smoking for this length of time, then their brain can return to normal functioning and normal stress and mood regulation ^[6].

Other mental health conditions related to smoking

Smoking is closely linked to several mental health conditions, with research suggesting that people with a mental illness are far more likely to smoke, begin smoking at a younger age, smoke more heavily, and be more dependent on nicotine, than the general population ^[3].

This may be due to similar risk factors for mental illness and smoking, smoking being used to control or manage mental health symptoms, or an increased risk of mental illness following prolonged smoking ^[6].

There is some evidence to suggest that smoking can increase the risk of certain mental health conditions, but this is currently unclear. Similarly, there is some evidence to suggest that mental illness increases the likelihood of smoking, although this is not always the case.

As such, the belief is that smoking and mental illness may increase the likelihood of one another in many cases, although they may not always be the cause of one another ^[3][6].

Anxiety

People with anxiety often report that they smoke to reduce their symptoms, believing smoking to be stress relieving. However, although smoking may cause a temporary relief from anxiety symptoms, it has been found to actually increase anxiety and stress. This can then lead to an increase in smoking, and thus a further worsening of symptoms ^[3][5].

There is a clear link between anxiety and smoking, but it is not clear if smoking causes anxiety or vice versa, or if the two exacerbate one another ^[2].

Schizophrenia

Studies show that people with schizophrenia are around 3-5 times more likely to smoke than the general population and tend to smoke more heavily. Many report that smoking helps to manage symptoms of schizophrenia and the side effects of antipsychotic medications, thus indicating that schizophrenia can lead to smoking ^[3][5].

There is some research that suggests that early and prolonged smoking can increase the likelihood of schizophrenia development, although this currently remains uncertain and requires further research ^[7].

Posttraumatic stress disorder (PTSD)

Studies have found that smokers are around twice as likely to have PTSD than non-smokers, and people with PTSD are around twice as likely to smoke as those without. This indicates that there is a clear link between PTSD and smoking, although it is not clear exactly how one influences the other ^[8].

Bipolar disorder

Research suggests that people with bipolar disorder are more likely to be heavy smokers than those without, suggesting that the condition may lead to an increase in smoking. Similarly, research indicates an increased risk of bipolar disorder in those who smoke at a younger age and for a prolonged period, although these results need further corroboration and confirmation ^[9][10].

Top tips on how to quit smoking

Quitting smoking can improve your mental and physical health, although it can feel challenging and unmanageable. There are several ways to improve your ability to quit smoking, such as ^[4][5]:

• Pick a good time: Trying to quit when you are experiencing a lot of stress, difficulties, or emotional distress may make it harder to quit, so try and pick a time when you are feeling strong and motivated to give you the best chance at success.
• Speak to a professional: There are people and services who can help in quitting, by providing advice and guidance to aid the process, or who can prescribe a medication that can help. Similarly, it is important to discuss quitting smoking with your doctor if you take any prescribed medication, as this may need to be altered.
• Replacements: Try using nicotine replacement therapy (NRT), which can include inhalators, gum, and patches, or e-cigarettes, as these can be helpful replacements for cigarettes to aid you in the quitting process.
• Have a goal or motivation: It can be helpful to remind yourself why you want to quit, such as wanting to get fit or wanting to save money for a holiday.
• Keep trying: For some people it can take several attempts at quitting before completely staying off cigarettes. If this is the case, keep trying and don’t get disheartened; instead try to learn from each attempt, considering what did and didn’t work for you, so that you can use these lessons for the next attempt and increase your chances of success.
• Find other ways to manage stress: If you have always smoked as a stress relief, it can be useful to find other ways to manage stress, such as relaxation or breathing exercises, meditation, yoga, running, walking, or talking to a friend or professional.
• Avoid alcohol: Alcohol can worsen physical and mental health and contribute to cigarette cravings, so avoiding alcohol can be helpful when trying to quit smoking.
• Eat healthily: Eating a balanced diet and drinking plenty of water can help to improve physical and mental health, thereby reducing symptoms of depression and anxiety that might lead to cravings, as well as helping to reduce the severity of withdrawal symptoms.