A recent systematic review suggested that physical therapy is effective, but there is only moderate evidence to support this conclusion.

A 1998 systematic review of studies assessing its prevalence in 13 countries concluded that about 31 % of cancer patients use some form of complementary and alternative medicine .< ref name = Ernst_Cassileth > Alternative medicine varies from country to country.

A systematic 2003 review of controlled clinical trials related to the Alexander Technique found two reputable studies suggesting the Alexander Technique is effective in reducing the disability of patients suffering from Parkinson ’ s disease and improving pain behaviour and disability in patients with back pain, and concluded that the evidence supporting the effectiveness of the Alexander Technique is encouraging but not convincing.

A systematic review of randomized controlled trials published in the Archives of General Psychiatry showed up to one-third of the six-week effect of SSRI treatment can be seen in the first week.

Nevertheless, a 2009 systematic review and meta-analysis of trials in people diagnosed with schizophrenia found that less than half ( 41 %) showed any therapeutic response to an antipsychotic, compared to 24 % on placebo, and that there was a decline in treatment response over time, and possibly a bias in which trial results were published.

A systematic review by the Cochrane Collaboration found no studies of sufficient quality to make any statement on the efficacy of the vaccine.

Guidelines issued by the UK-based National Institute for Health and Clinical Excellence ( NICE ), carried out a systematic review using different methodology and came to a different conclusion.

However, controversy exists as to tolerance to the anxiolytic effects with some evidence that benzodiazepines retain efficacy and opposing evidence from a systematic review of the literature that tolerance frequently occurs and some evidence that anxiety may worsen with long-term use.

A systematic review of CBT in depression and anxiety disorders concluded that " CBT delivered in primary care, especially including computer-or Internet-based self-help programs, is potentially more effective than usual care and could be delivered effectively by primary care therapists.

A systematic review found that the risk of death from manipulations to the neck outweighs the benefits.

“ Health effects of Relocation following disasters: a systematic review of literature ”.

Using techniques from science, engineering and statistics, such as the systematic review of medical literature, meta-analysis, risk-benefit analysis, and randomized controlled trials ( RCTs ), EBM aims for the ideal that healthcare professionals should make " conscientious, explicit, and judicious use of current best evidence " in their everyday practice.

The systematic review of published research studies is a major method used for evaluating particular treatments.

A 2001 review of 160 Cochrane systematic reviews ( excluding complementary treatments ) in the 1998 database revealed that, according to two readers, 41. 3 % concluded positive or possibly positive effect, 20 % concluded evidence of no effect, 8. 1 % concluded net harmful effects, and 21. 3 % of the reviews concluded insufficient evidence.

The second area is the systematic review of medical literature to evaluate the best studies on specific topics.

For example, the strongest evidence for therapeutic interventions is provided by systematic review of randomized, triple-blind, placebo-controlled trials with allocation concealment and complete follow-up involving a homogeneous patient population and medical condition.

It concludes from a systematic review of available research that,

*" A systematic review has found that hypnosis enhances the effects of cognitive behavioural therapy for conditions such as phobia, obesity, and anxiety.

According to a systematic review by the Cochrane Collaboration, the best evidence in the treatment of LEMS exists for 3, 4-aminopyridine and IVIG.

A systematic review of the literature related to PID treatment was performed prior to the 2006 CDC sexually transmitted infections treatment guidelines.

Consequently, a systematic review by the Cochrane Collaboration ( published in 2008 ) found insufficient evidence to recommend the use of silver-treated dressings to treat infected wounds.

A systematic review by the Cochrane Collaboration found no studies of sufficient quality to make any statement on the efficacy of the vaccine.

In a systematic review including two prospective studies of 47, XYY boys identified by newborn screening programs and one retrospective study of 47, XYY men identified by screening men over 184 cm ( 6 ' 0 ") in height, forty-two 47, XYY boys and men had an average 99. 5 verbal IQ and 106. 4 performance IQ .< ref name =" Ratcliffe 1994 ">

In a recent systematic review of eight trials of day care for disadvantaged children under 5 years of age, long term follow up showed lower pregnancy rates among adolescents.

" In 2003, The UK ECT Review group published a systematic review and meta-analysis comparing ECT to placebo and antidepressant drugs.

Adorno concluded that astrology was a large-scale manifestation of systematic irrationalism, where individuals were subtly being led to believe that the author of the column was addressing them directly through the use of flattery and vague generalizations.

A 2007 analysis of 1016 systematic reviews from all 50 Cochrane Collaboration Review Groups found that 44 % of the reviews concluded that the intervention was " likely to be beneficial ", 7 % concluded that the intervention was " likely to be harmful ", and 49 % concluded that evidence " did not support either benefit or harm ".

Petrie, author of Pyramids and Temples of Gizeh concluded: " but these relations of areas and of circular ratio are so systematic that we should grant that they were in the builder's design ".

In their report, the delegation organized by the Division of Overseas Ministries of the National Council of Churches of Christ in the United States concluded that there is ' no basis for the charge of systematic religious persecution '.

A 2007 systematic review concluded that treatment with HBOT showed no significant difference from that of pressurized room air, and that some children undergoing HBOT may experience adverse events such as seizures and the need for ear pressure equalization tubes ; due to poor quality of data assessment the review also concluded that estimates of the prevalence of adverse events are uncertain.

In July 2006, they published " Report into Allegations of Organ Harvesting of Falun Gong Practitioners in China ", which concluded that large numbers of Falun Gong practitioners were victims of systematic organ harvesting throughout China, while still alive ..

" A systematic review concluded: Spinal cord stimulation appears to be an effective therapy in the management of patients with CRPS type I ( Level A evidence ) and type II ( Level D evidence ).

He concluded that there is a systematic error in the Cassini radio Doppler data used in the analysis, but after restricting the analysis to a subset of data obtained closest to the moon, he arrived at his old result that Rhea was in hydrostatic equilibrium and had the moment inertia of about 0. 4, again implying a homogeneous interior.

In a 2005 meta-analysis and systematic review of six randomized controlled trials of osteopathic manipulative treatment ( OMT ) that involved blinded assessments of lower back pain in ambulatory settings, it was concluded that OMT significantly reduces low back pain, and that the level of pain reduction is greater than expected from placebo effects alone and persists for at least three months.

This view was notably challenged when, in 2001, a systematic review of clinical trials concluded that there was no evidence of clinically important effects, except perhaps in the treatment of pain and continuous subjective outcomes.

The concept of ki underlying Reiki is speculative and there is no scientific evidence that it exists ; a 2008 systematic review of randomised clinical trials concluded that " the evidence is insufficient to suggest that reiki is an effective treatment for any condition.

A 2008 systematic review of randomised clinical trials assessing the evidence basis of reiki concluded that efficacy had not been demonstrated for any condition.

A systematic review in 2009 concluded:

A newer systematic review published in 2010 by Ernst concluded All placebo-controlled trials failed to demonstrate efficacy.

One of the most extensive and systematic studies to review the safety of Echinacea products concluded that overall, " adverse events are rare, mild and reversible ," with the most common symptoms being " gastrointestinal and skin-related.

In comparing the options, a systematic review found that benzodiazepines and nonbenzodiazepines have similar efficacy that is not significantly more than for antidepressants.

In a major systematic review published in 2009 which compared the efficacy and tolerability of 12 popular antidepressants, mirtazapine was found to be superior to all of the included selective serotonin reuptake inhibitors ( SSRIs ) and serotonin-norepinephrine reuptake inhibitors ( SNRIs ), and reboxetine, bupropion, and mianserin in terms of antidepressant efficacy, while it was average in regards to tolerability.