Almost 100 Wiltshire police officers and staff have sought psychological support after the nerve agent attack in Salisbury, the Guardian can reveal.

Among those who have asked for help were officers who initially responded to the collapse of the former Russian spy Sergei Skripal and his daughter, Yulia, and those who were at or close to the various investigation sites in subsequent days and weeks.

Some reported feeling disorientated and anxious while others were concerned about the possible long-term health effects on the public.

Wiltshire’s chief constable, Kier Pritchard, told the Guardian that officers – including himself and other police personnel continued to receive help more than two months after the attack.

Pritchard took up the role of head of the force on the day of the attempted murders and said he had personally received the “best support” as he worked through the implications for him and his family of being a high-profile figure in the response to a state-sponsored attack.

One police officer, DS Nick Bailey, spent more than two weeks in hospital after being exposed to the novichok nerve agent and when he was discharged said life would never be the same again.

Quick Guide What is novichok? Show Novichok refers to a group of nerve agents developed by the Soviet Union in the 1970s and 80s to elude international restrictions on chemical weapons. Like other nerve agents, they are organophosphate compounds, but the chemicals used to make them, and their final structures, are considered classified in the UK, the US and other countries. The most potent of the novichok substances are considered to be more lethal than VX, the most deadly of the familiar nerve agents, which include sarin, tabun and soman. Novichok agents work in a similar way, by massively over-stimulating muscles and glands. Treatment for novichok exposure would be the same as for other nerve agents, namely with atropine, diazepam and potentially drugs called oximes. The chemical structures of novichok agents were made public in 2008 by Vil Mirzayanov, a former Russian scientist living in the US, but the structures have never been publicly confirmed. It is thought they can be made in different forms, including as a dust aerosol. The novichoks are known as binary agents because they only become lethal after mixing two otherwise harmless components. According to Mirzayanov, they are 10 to 100 times more toxic than conventional nerve agents. Photograph: Matt Cardy/Getty Images Europe

But Pritchard revealed more than 90 officers and staff had received support through the trauma risk management (Trim) programme, a police scheme based on a project developed by the Royal Marines.

Trim practitioners are police officers and staff trained to help traumatised colleagues through an event that has caused physical, emotional or psychological harm.

Pritchard said officers responding to the attack on 4 March had believed they were helping at a medical episode, possibly drugs related.

“I’ve watched the body cam footage that was recording what they did that day. The response was absolutely first class,” he said.

“We have had over 90 of our officers and staff come forward to receive support through the Trim process. That is based upon the impact of either attending the scene, the fear they may have been exposed to a chemical incident, the psychological impact of how the situation unfolded and the uncertainty of the public health advice and information.”

He added that it was a “high stress” situation and those at “the sharp end” were disorientated and anxious.

Asked about his own reaction, Pritchard said: “It was my first day. It wasn’t the first day I was expecting. It was a privilege despite the fact that the circumstances were unprecedented and horrific. It was a privilege to take the role as the figurehead of the operation on the global stage.

“Any incident like this will make you stop and reflect about impact on yourself, your family. You start to think about the implications for you as someone who has been a prominent figure in the response.

“But I’ve been given the best support that is available to me, I’m used to speaking to our occupational health unit on a very frequent basis. I think it’s really positive as leader to demonstrate that is OK for the leader to do things in the right way too.”

Pritchard, who was speaking during Mental Health Awareness Week, said he saw the number of police personnel who had asked for help after the Salisbury attack as a sign of success.

He said: “We’ve opened our doors, we’ve provided the right resources and people are prepared to say: ‘I could do with some help, advice, support.”

Pritchard said Wiltshire and other forces had worked hard to tackle the “macho” culture in which admitting mental health issues was seen as a weakness.

As well as investing in the occupational health unit and Trim, the force had signed up to the Blue Light programme, which encourages staff to talk about mental health issues.

Pritchard revealed that after the suicide of a colleague he sought help through Trim. “I wasn’t coping well at work or at home; I wasn’t sleeping well, I was anxious and irritable, I felt angry, guilty and sad – a whole host of emotions – and I could see that my work and family were suffering.

“The force offered me Trim. Once I’d accepted that I needed help, I really embraced the whole process and felt as though a weight had been lifted from me. My reaction, as is the case for many, was normal – it was the event that was abnormal.”

Pritchard said the nature of the job meant officers and other police personnel may be more at risk of mental health problems than the general public as a whole, but added that cuts to police numbers were increasing the pressure.