The mystery surrounding the sudden death of the 20-year-old son of Anna Nicole Smith has finally been solved and, as the first autopsy indicated, it was caused by drugs, the toxicology test revealed yesterday.

Although Daniel was not a drug addict, at the time he visited his mother in Bahamas, he was using two anti-depressants to help him get over an alleged break-up with a girlfriend. Zoloft and Lexapro are two prescription drugs, usually used in treating depression and insomnia and they are not lethal, even if combined.

It was a third drug, methadone, that made the combination dangerous, speeding the heart beat of the young man. The combo, associated with the happy occasion for which Daniel was in Bahamas (the birth of a baby sister), led to a 'cumulative effect on the central nervous system' and made it collapse.

The fact that Daniel was taking the anti-depressants was proved by the prescriptions he had but it is yet unsure why he was taking methadone, a drug usually used by heroin-addicts to help their body get accustomed to not using the class A drug. In recent years, it has been described as a powerful painkiller, a thing confirmed by Anna Nicole's attorney too (who stated for a fact that Daniel was not a drug addict), although he was not able to say whether Daniel had a prescription for it or not.

The toxicology test confirmed that there was no foul play in Daniel's death and that, as it has been speculated, it was accidental. 'The fact that we have these drugs and the levels of the drugs overwhelmingly and most logically point to this being a tragic, accidental and drug-related death', Cyril Wecht, an US-based pathologist said after the toxicology test was made public. The young man's death was not a suicide, he added.