Five women whose bodies were found in the Ipswich area may have been unable to fight off their killer because they were high on drugs, a court heard.
Anneli Alderton had taken cocaine before she died, the court heard
Pathologist Dr Nathaniel Cary told jurors the women may have been too intoxicated to resist attack.
Gemma Adams, 25, Paula Clennell, 24, Tania Nicol, 19, Anneli Alderton, 24, and Annette Nicholls, 29, were working as prostitutes when they disappeared.
Mr Wright, 49, on trial at Ipswich Crown Court, denies their murders.
The five women were found dead over 10 days in December 2006, two of whom - Miss Alderton and Miss Nicholls - were left in a crucifix pose, the court has heard.
The bodies were all found naked and appeared to have been dumped - circumstances that rule out the possibility they died accidentally from an overdose, Dr Cary told the court.
"These were individuals who may have not gone a single hour in a day without some drug on board," he said.
"[But] these are not simply what we would call drug overdose cases... because of the circumstances of the disappearances and the dumpings of the bodies and the fact that they were all naked."
However, intoxication through drugs may have made it easier for someone to kill them, the jury was told.
"Someone may have been so intoxicated they simply would not resist," Dr Cary said.
The pathologist described how Miss Adams and Miss Nicol were both found dead in rivers, the first on 2 December and second on 8 December.
Despite believing Miss Adams' body had been put in the water soon after she died, Dr Cary said the time of death could not be accurately determined by examining her body.
Dr Cary examined the bodies of the five women
"It's usually not that simple from examination of the body," he told the court.
"Nowadays last use of the telephone can be terribly important, [for example]."
Dr Cary said there were no injuries on Miss Adams' body consistent with her having been strangled, but he said he could not exclude the theory she had been asphyxiated after being put in an arm lock from behind.
Because of the condition of Miss Nicol's remains the cause of death could not be ascertained, Dr Cary said.
He told the court that he had found significant levels of morphine - probably derived from heroin - in Miss Nicol's blood.
As with Miss Adams, he said he had considered the theory she had been asphyxiated, but it is possible she had drowned.
Both Miss Nicol and Miss Alderton, whose body was found on 10 December in woodland at Nacton, had bruising.
On Miss Nicol, they were consistent with having been "manhandled", the court was told.
It could be concluded that from the condition of Miss Alderton's body, she had been asphyxiated, Dr Cary said.
Tests showed she died within hours of her disappearance, on 3 December, and had been "significantly under the influence of cocaine", he added.
Miss Nicholls and Miss Clennell were found on 12 December.
Dr Cary said he could not ascertain a cause of death for Miss Nicholls, but could not rule out asphyxia.
However, the condition of Miss Clennell's body was consistent with her being asphyxiated.
The trial was adjourned until Thursday, when Dr Cary is expected to complete his evidence.