Two senior consultant psychiatrists are in conflict over the mental state of a man who admitted to killing his two-year-old son, a court has heard.

Dr Khuram Khan assessed Lukasz Czapla after his son Julius was found dead at his flat in Muirhouse in Edinburgh in November 2020.

After multiple interviews, the psychiatrist said the 41-year-old has or had Emotionally Unstable Personality Disorder (EUPD), a condition that causes intense fluctuations of emotions among other symptoms including depression and impulsivity.

Earlier, psychiatrist Dr Alexander Quinn, who also assessed Czapla after the death of his son, agreed Czapla had a “depressive illness”, but that it “was not severe” and dismissed the EUPD diagnosis.

The court has previously been told Czapla, a former IT technician, had been struggling with depression, which intensified after his seven-year relationship with his former partner Patrycja Szczesniak ended just months before Julius was killed.

At a hearing at the High Court in Edinburgh on Thursday, Alan Cameron, prosecuting, put some of Dr Quinn’s comments about Czapla to Dr Khan in which he said there was “an absence of indicators that you might see in EUPD, and spoke of his time in prison and said he did not present as someone with EUDP.”

Dr Khan, before a 15-strong jury, defended his diagnosis of the accused.

A statement of his was read out in court which said: “In my view, his (Czapla) long-standing complaint about depression symptoms should be seen within the context of EUPD.

“Patients with EUPD can present symptoms of depression such as low mood, anhedonia (inability to feel pleasure) and irritability.

“They have difficulty in managing or regulating emotions and are often described as having low mood lability.”

His went on to say: “Therefore, my view is different from Dr Quinn’s formulation in relation to the primary diagnosis.

“I believe that Mr Czapla does not/did not have frank major depressive disorder, rather his depressive symptoms are or were secondary to the EUPD.”

Previous evidence has heard Czapla took an overdose of his anti-depressant medication and drank wine and beer on the night his son was killed, with the intention of taking his own life.

Dr Khan, in an initial report, said he believed the accused’s level of intoxication played a more substantial role to Czapla’s mental state in the killing of his son.

But after further assessment, Dr Khan said, on the balance of probabilities, he believed EUPD played a “significant major role in the criminal act than what I previously thought.”

He said he was not in a position to confidently conclude whether diminished responsibility at the time of Julius’s death can be used in Czapla’s defence, and said this was ultimately a decision for the jury.

Iain McSporran QC, defending, had no cross-examination questions for Dr Khan.

Toxicologist Karen Kerr was called to give evidence about a blood sample that was taken from Czapla at about 5pm on 21 November 2020, the day his son was found dead.

The court heard the accused consumed drugs and alcohol late on 20 November and in the early hours of the next day.

He was found to have more than three times the “normal” amount of mirtazapine – an anti-depressant – in his blood.

The jury were told 0.08mg would be a standard level for someone prescribed the drug as medication, whereas Czapla’s test result showed 0.29mg.

The witness confirmed the level would have been higher closer to the time of consumption, but she could not dictate when exactly that would have been.

Ms Kerr went on to explain the “half life” – the amount of time it takes for a drug’s active substance in your body to reduce by half – of mirtazapine is between 20 to 40 hours.

She said because of the wide range, the higher level could also “reflect a steady intake” of the drug over a period of time, such as for someone who has been prescribed it.

Czapla was also found to have traces of amitriptyline and nortriptyline, also taken for depression, but Ms Kerr said these were low levels.

Evidence earlier revealed police breathalysed the accused that same day at 11.52am and found 33 micrograms of alcohol per 100ml of breath.

The limit in Scotland is 22mcg.

Czapla denies murdering the toddler in his home in November 2020.

He previously offered to plead guilty to the lesser charge of culpable homicide, but this was rejected by the Crown.

He has pleaded guilty to nine other charges which include dangerous driving, drug possession and having an air weapon.

The trial, before Lord Beckett, continues.