Vincent Van Gogh suffered from bouts of delirium due to alcohol withdrawal while he was in hospital being treated for his severed ear, researchers say.
On July 29, 1890, the 37-year-old Dutch painter died two days after shooting himself in the chest with a revolver.
Van Gogh's suicide came two years after he hacked off his ear and gave it to a maid in a brothel in Arles, France.
The bizarre act of self-harm marked the beginning of a mental decline which was punctuated by hallucinatory deliriums the artist suffered due to alcohol withdrawal, according to academics at the University of Groningen.
Van Gogh's subsequent hospitalisations in Arles, from December 1888 to May 1889, and his later transfer to the asylum of Saint-Rémy-de-Provence, have been analysed by psychiatrists at the university using his vast correspondence.
Vincent Van Gogh painted this self-portrait, 'Self-Portrait with Grey Felt Hat,' in the winter of 1887–88
They believe that Van Gogh, a heavy absinthe drinker, was suffering from delirium as a result of alcohol withdrawal on two occasions when he was first admitted to the medical facilities.
In 1888, Van Gogh, who had lived a nomadic existence, moved to Arles in the south of France.
Later that year, he was joined by fellow post-impressionist painter and friend Paul Gauguin.
But tempers flared between the pair and Gauguin wrote that he could not stand to live with Van Gogh 'as a result of incompatibility of temperament, and both he and I need tranquillity for our work.'
On December 22, Gaugin left abruptly in the night and Van Gogh was filled with anger which he took out upon himself.
The following evening he cut off his left ear and gave it to a woman in a brothel.
Two days later concerned police found the artist suffering from blood loss at his home and he was rushed to hospital.
It was here, Van Gogh would later write, that he experienced 'unbearable hallucinations.'
He wrote: 'My thoughts sailed over many seas. I even dreamed of the Dutch ghost ship (a mythical ship doomed to sail the seas forever) and the Horla (a contemporary horror story), and it seems that I sang then.'
The artist remained in hospital for a week before he was discharged.
But just a month later Van Gogh returned with the same symptoms, vivid hallucinations and amnesia.
He left the hospital after ten days but when he returned to his studio there were complaints from local residents that he had inappropriately touched women and made obscene comments.
This prompted his third involuntary admission and resulted in 'terrible fits of anxiety sometimes without any apparent cause.'
In March, Van Gogh was able to return home again but he would later agree with his doctor to go to the asylum in Saint-Rémy on May 8, 1889.
Van Gogh's 'Still Life with Absinthe', a tribute to his drink of choice
The great painter stayed here for a year during which he suffered four 'mental crises,' the Groningen psychiatrists write.
Van Gogh described his 'disturbed mind' and told a friend he was 'absolutely distraught, as in Arles, just as much if not worse'.
He noted his unusual behaviour, saying he ate dirt and he was also observed eating paint – some believe an attempt at poisoning himself.
In May 1890, he gave up on recovering at the asylum and moved north to Auverssur-Oise, a rural commune outside Paris where he would fatally shoot himself two months later.
Van Gogh was an alcoholic for much of his life. He attempted to reduce his consumption in Arles but was largely unsuccessful.
In addition to beer and wine, he drank the spirit absinthe which in those days had an alcohol content of between 50 and 70 percent.
He also didn't eat very much and this malnourishment coupled with the drinking could have caused serious neural impairment, according to the researchers.
'Moreover, abrupt stopping with excessive alcohol consumption can lead to withdrawal phenomena, including a delirium.' The paper says.
'Therefore, it is likely that at least the first brief psychosis in Arles on the days after the ear incident during which he likely stopped drinking abruptly, was actually an alcohol withdrawal delirium.
'Only later on in Saint-Rémy, when he was forced to minimize or even stop drinking, he probably succeeded in it and he also did not have further withdrawal problems.'
The academics further note that they believe Van Gogh suffered from bipolar disorder and that he had a personality disorder from a young age.
These are not new theories and the academics point to the painter's strained love life, his self-destructive behaviour and tumultuous relationships with his father and brother, among others.
The paper says that these problems were later exacerbated by alcohol and malnutrition, leading to his cutting off his ear.
He then developed two deliriums, they theorise, probably down to alcohol withdrawal and leading to worsened depression.
He was unable to recover and finally killed himself.