People with bipolar disorder characterised by extreme mood swings are six times more likely to die before their time from external causes, such as accidents, violence, and suicide, than those without the condition, finds research. 

The study, published in the open-access journal BMJ Mental Health, showed that people without the disorder are twice as likely to die from somatic (physical) causes, with alcohol a major contributing factor, the findings show.

"A balanced consideration between therapeutic response, potential serious long-term somatic side effects of different medicines, and risk of cause-specific premature mortality is needed, especially in younger persons," said researchers including Dr. Tapio Paljarvi, Niuvanniemi Hospital in Finland.

"Targeting preventive interventions for substance abuse will likely reduce the mortality gap both due to external causes and somatic causes. Suicide prevention remains a priority, and better awareness of the risk of overdose and other poisonings is warranted," they added.

A heightened risk of early death from any cause has been consistently reported in those with bipolar disorder from several countries. But it's not clear if there are particular drivers, or to what extent somatic illness or physical disease contributes to this risk.

To understand this, the team tracked the outcomes of 47,018 people with bipolar disorder for eight years. 

In all, 3,300 (7 per cent) of them died during the monitoring period compared with 141,536 people in the general population, equating to a 6-fold higher risk of death from external causes and a 2-fold higher risk of death from somatic causes.

Their average age at death was 50, almost two-thirds (65 per cent) of these deaths were among men. The cause of death was somatic in 61 per cent and external in 39 per cent.

Among the 2,027 somatic illness deaths, alcohol caused the most at 29 per cent; followed by heart disease and stroke (27 per cent); cancer (22 per cent); respiratory disease (4 per cent); diabetes (2 per cent); and behavioural disorders associated with other substance misuses (1 per cent).

The remaining 15 per cent comprised various other causes. Of the 595 alcohol-related deaths, liver disease accounted for nearly half (48 per cent), followed by accidental alcohol poisoning (28 per cent), and alcohol dependence (10 per cent).

Among the external cause deaths, most were due to suicide (58 per cent), nearly half of which (48 per cent) were due to overdose with prescribed mental health meds, including those used to treat bipolar disorder. 

Overall, nearly two-thirds (64 per cent) of the deaths from any cause were excess deaths. Of these, 61 per cent (651) were due to suicide, a proportion that is around 8 times higher than that of the general population.

Given that external causes seem to have a more significant role than physical illness in excess deaths among those with bipolar disorder, the current therapeutic focus on preventing physical illness to reduce this excess should be reconsidered, the researchers argued.