A common medication taken by millions turned my kind father into a killer: He stabbed my five-year-old twin sisters to death… but I forgive him

The school intercom crackled and Jessica Barrett’s name was called for her to go to the front office. She was 17, a high school senior in Charlotte, North Carolina, thinking about graduation, friends and college applications.

‘I thought I must be in trouble and couldn’t think why,’ she recalls.

But waiting for her outside the school office was a police officer – and something in his expression made her stomach drop.

He wouldn’t say what had happened, only that it involved her father and that she needed to accompany him to the station.

At the station, she was reunited with her two younger brothers, Dylan, then 13, and Josh, nine, who’d also been collected separately from school without explanation. They sat together, waiting, with no idea what was coming.

Then came the sound that still haunts Jessica 20 years later: her mother Kim’s voice, outside the door, asking ‘what do I tell them?’

When Kim entered the room she looked up and said: ‘They’re telling me your father killed your sisters.’

On January 20, 2006, David Crespi, a 45-year-old businessman and father of five with no history of violence, stabbed his five-year-old twin daughters, Tessa and Samantha, at the family home in South Charlotte.

He later pleaded guilty to both murders – and is now serving two consecutive life sentences.

The case horrified America. Journalists speculated about financial pressure, hidden darkness, a family façade. Now, speaking publicly for the first time, Jessica believes they had the wrong explanation entirely.

Jessica – now 37 – believes her father did what he did because of a severe, adverse reaction to medications he’d been prescribed for anxiety and depression, following a stressful period at work and being unable to sleep.

‘Without those drugs my sisters would still be alive today,’ she says.

Jessica agreed to share her story with me because of my years investigating the adverse effects of psychiatric drugs, following my own experience, after being prescribed an antidepressant in 2012 for insomnia.

I suffered a toxic delirium that led to hospitalisation – and further psychiatric medications, leaving me unwell for months. My recovery began only after I was withdrawn from the drugs.

Jessica is speaking now, she says, so that other families – and doctors – might recognise the warning signs of these rare but potentially devastating reactions.

Seven days before the killings, Jessica’s father started taking the antidepressant Prozac, added to an existing cocktail of Ambien (a sedative) and trazodone (another type of antidepressant). The night before he was also given Lunesta (a drug for insomnia) having been diagnosed with stress and anxiety.

The family are convinced this combination triggered the psychotic state that destroyed their lives.

Jessica’s childhood before that January morning was loving and happy, she says.

Her biological mother died when she was five, and in the aftermath her father raised her and her younger brother alone. The loss could have defined them. Instead, her father was determined it wouldn’t.

‘He was incredibly funny,’ says Jessica. ‘If I was ever upset about something, he really wanted to understand and help.’

She still carries one particular memory from that time.

‘My brother was still a baby, so my dad took just me to Disney World,’ she says.

‘I remember it as this really happy time. He bought me a costume of a Disney princess he knew I loved. He wanted me to feel joy again.’

When her father married Kim the next year, who eventually adopted the children, the family expanded quickly into a warm and loving household.

‘There were suddenly grandparents, cousins, all these extra people loving us,’ says Jessica. ‘It instantly felt like a family.’

When Tessa and Samantha were born, Jessica, then 12, was besotted – as was her dad. She says: ‘He lived for his kids. I remember him playing with them on their scooters and bikes.’

But Jessica believes there were warning signs of what was going to unfold that went unrecognised.

For many years, David had cycled through periods of psychiatric medication; something the family were well aware of.

Stress at work would trigger insomnia, and doctors would prescribe accordingly: sleeping pills first, then anti-anxiety medication, then antidepressants. Each time, the family watched him change.

‘Dad would become different,’ says Jessica. ‘Agitated. Withdrawn. His teeth would chatter even when it wasn’t cold. He couldn’t sit still.’

Agitation, restlessness, emotional blunting and profound changes in behaviour are all recognised side-effects of some psychiatric drugs, though experts do not know why certain people experience severe reactions while most do not.

Researchers believe genetic differences in the way individuals metabolise medications may play a role.

Jessica says: ‘Eventually he’d wean himself off the medication as it didn’t seem to help, turn to exercise and nutrition, and gradually become himself again. The family accepted it as simply the way things were.’

The final deterioration was rapid. Two weeks earlier, Jessica recalls, her father had been warm and engaged; ‘Just his usual self.’

But after Prozac was added to his existing medications, Jessica noticed her father becoming increasingly detached, absorbed in his own thoughts, and pacing the house constantly.

‘It was almost like he physically couldn’t stop moving,’ she says.

This, the family now believes, is key.

Immediately after the murders, detectives took the family to a hotel under police escort, the street around their home now a crime scene crowded with police cars and news crews.

‘We were all so shocked that we sat in silence,’ says Jessica.

She found herself staring at her sisters’ empty car seats: ‘I just kept thinking: they’re never going to sit in those seats again.’

But she adds: ‘I barely cried immediately after as I was in such shock. I couldn’t reconcile what happened with the father I knew.’

Inside the hotel room, neighbours had left food waiting for them. People arrived in droves, including extended family who flew in from California, neighbours and school friends.

Jessica recalls: ‘People would hug us and cry and say: “How could this happen?” and we’d just say: “We don’t know.”‘

That night Jessica sat awake in the dark after her younger brothers had finally fallen asleep.

‘It felt like there had been an explosion in our family, and we were sitting in the fallout of it,’ she says.

‘I just felt numb. I just couldn’t imagine that my dad had done this. I played the scene over and over in my mind but I couldn’t accept it.’

Detectives questioned the family repeatedly, searching for a motive.

‘They were searching for some hidden explanation – but there wasn’t one,’ she says.

The media frenzy deepened the confusion.

Television coverage speculated that David may have snapped under pressure from supporting a large family and maintaining an expensive lifestyle. But ‘nothing about it added up’ for Jessica.

‘We lived in a three-storey house and were comfortable, but I remember thinking: if somebody was truly that desperate financially, why would they only kill the twins?’

Returning to school two weeks later was surreal. Suddenly, everyone knew who she was.

Jessica recalls: ‘People talked about my dad like he was a monster. I kept thinking: you don’t know him,’ she says, feeling defensive of her father – but deeply alone with it. All the while, grieving her sisters.

Concentrating on anything in class was impossible.

Months later, the family went to see David in prison for the first time.

‘I was terrified of what I was going to find when I saw dad,’ recalls Jessica.

‘But the man sitting behind the prison glass was unrecognisable. He was speaking very slowly. Rocking, breathing heavily and looking away constantly, like he was trapped inside his own mind,’ Jessica recalls.

‘Looking back, I believe that was because prison psychiatrists had diagnosed him with bipolar disorder and put him on additional medication, including lithium.’

David’s guilty plea came shortly after. In North Carolina, where the death penalty remains in use, pleading guilty was the only way to avoid execution.

In court, six months later, he apologised repeatedly for killing his daughters.

‘But he didn’t even sound like himself,’ says Jessica. ‘There was just this flatness.’

In the months after the killings, with detectives unable to find a motive and the media offering only speculation, Jessica’s mother Kim came across a book – by renowned psychiatrist Dr Peter Breggin called Medication Madness – which documents cases of violence and psychosis linked to psychiatric drugs.

It led the family to something called akathisia – a recognised neurological condition linked to medications such as antidepressants and antipsychotics – characterised by extreme agitation and physical restlessness.

‘I started thinking back to those earlier episodes,’ says Jessica. ‘The pacing, the agitation. Suddenly it all lined up.’

In the most serious cases, akathisia has been linked to suicide, violence and psychosis.

Experts believe the panic and sense of inner torment can leave someone unable to think clearly or control their impulses.

In rare cases, particularly when accompanied by paranoia, delusions or psychotic symptoms, that distress may be directed towards other people as well as themselves.

In the course of their research – about a year after David’s conviction – the family discovered that courts around the world have sometimes accepted involuntary intoxication as a legal defence in cases where defendants may have committed violent acts as a result of an adverse reaction to antidepressants.

It’s a defence David’s family believe should have been available to him. However, lawyers told them there was no legal precedent in the US. Jessica has since watched police interview footage of her father hours after the killings, obtained through lawyers helping her dad.

In it, he is constantly moving a cup backwards and forwards on the table and rocking in his chair.

‘It looked very much like my dad had akathisia,’ she says.

Her certainty deepened years later when, aged 22, she suffered her own frightening neurological reaction to an anti-sickness drug prescribed for nausea, developing tardive dyskinesia – a condition involving involuntary, uncontrollable movements.

‘That gave me a tiny glimpse into what it feels like when your body and brain no longer feel fully under your control,’ she says. ‘It changed how I understood what happened to my dad.’

Over the years, therapists have repeatedly offered Jessica antidepressants and anti-anxiety drugs to help with the trauma of her sisters’ deaths. She always refused.

‘I kept thinking: if this happened to my dad, how can anyone tell me it couldn’t happen to me?’

Instead, she has built what she describes as a mental health toolbox: walking, breathing exercises, prayer, time outdoors, animals, somatic therapy (which focuses on the connection between mind and body and calming the nervous system).

Meanwhile, inside Albemarle Correctional Institution, where David has now spent nearly two decades, his own relationship with medication also shifted.

A year after his conviction, David’s psychiatric drugs – he was taking lithium, Lexapro (escitalopram, an SSRI antidepressant) and risperidone (an antipsychotic) – began affecting his kidney and liver function, and he was slowly taken off them.

What followed was another turbulent period. Jessica describes manic letters arriving filled edge to edge with writing, and rambling, frantic phone calls.

Then, slowly, something changed.

‘In 2009, about a year after he came off all the medications, I started feeling like I had my dad back,’ says Jessica.

‘He cried when he talked about Tessa and Samantha for the first time. He had a full range of emotions again. That was huge for me.’

‘My dad went on his own researching journey, discovering cases where medication had caused a psychotic episode – he still blamed himself, because he’d made the choice to take the drugs, but at least it gave him an explanation.’

After years of anger, Jessica says she’s forgiven her father.

It’s not because she’s minimised what happened, but because she believes she understands it.

‘I can separate the father I knew from the psychotic state he entered,’ she says. ‘That took years. But I got there.’

Today, the ordinary shape of her adult life – married to Ryan and living in Denver, North Carolina, where she works as a provider data specialist – sits alongside a grief that never fully lifts.

Her adoptive mother Kim, now 65, who stood by her husband throughout, now has severe Parkinson’s disease. Before the illness progressed, Jessica drove her to prison visits regularly.

‘We all still love him,’ she says simply.

For years David phoned and wrote regularly from prison.

‘He always hoped someone would eventually understand what happened to him,’ says Jessica. ‘That maybe one day he’d come home.’

More recently, the contact has dwindled.

Jessica wonders whether hopelessness has finally overtaken him. She pauses.

‘I miss my sisters every single day. There’s no fixing a loss like this.’

‘But I believe my dad should be freed. He’s now been off all psychiatric medication for 17 years. I just wish somebody had known what the drugs were doing to him.’

Jessica is interviewed on The Med Free Mental Fitness Podcast with Katinka Blackford Newman, available YouTube, Spotify and Apple podcasts