May 29 (HealthDay News) -- Aggressive treatment of patients with whiplash doesn't speed their recovery, Canadian research suggests.

University of Toronto researchers examined the treatment received by almost 1,700 whiplash patients.

They found that increasing the intensity of care to more than two visits to a general practitioner, or adding chiropractic care to general practitioner care, was actually associated with slower recovery.

The results, published in the June issue of the journal Arthritis Care & Research, reaffirmed earlier findings by the same research team.

Whiplash is a common traffic crash-related injury that causes neck pain, headaches and other symptoms that can lead to significant disability and use of the health care system.

The study authors noted that practice guidelines recommend treatment shortly after a patients suffers whiplash and that effective care, if medically needed, can improve patient prognosis.

However, the researchers noted that doctors, under pressure from patients, often provide treatment, schedule follow-up visits, and refer patients to specialists when such actions are not medically needed.

"This in turn may lead to adverse outcomes and even prolong recovery by legitimizing patients' fears and creating unnecessary anxiety," the study authors wrote.

Early aggressive treatment may also delay recovery by encouraging the use of passive coping strategies on the part of patients.

"Reliance on frequent clinical care, a form of passive coping strategy, may have a negative effect on recovery by reinforcing the patients' belief that whiplash injuries often lead to disability," the authors wrote.