Autistic people may be severely impaired in some respects but average, or even superior, in others.Clinicians consider assessment for ASD when a patient shows:

regular difficulties in social interaction or communication
restricted or repetitive behaviors (often called "stimming")
resistance to changes or restricted interestsThese features are typically assessed with the following, when appropriate:

problems in obtaining or sustaining employment or education
difficulties in initiating or sustaining social relationships
connections with mental health or learning disability services
a history of neurodevelopmental conditions (including learning disabilities and ADHD) or mental health conditions.There are many signs associated with ASD; the presentation varies widely:
Atypical eating is also common, but it does not need to be present to make a diagnosis.In addition, a small percentage of autistic people can exhibit notable ability, for example in mathematics, music or artistic reproduction, which in exceptional cases is referred to as savant syndrome. Developmental course
There are two possible developmental courses of ASD. One course of development is more gradual in nature, with symptoms appearing fairly early in life and persisting. A second course of development is characterized by normal or near-normal development before onset of regression or loss of skills, which is known as regressive autism. Gradual autism development
Most parents report that the onset of autism features appear within the first year of life. This course of development is fairly gradual, in that parents typically report concerns in development over the first two years of life and diagnosis can be made around 3–4 years of age.
Professional divers use such a calculation only as a rough guide to give new divers a metaphor, comparing a situation they may be more familiar with.Reported signs and symptoms are summarized against typical depths in meters and feet of sea water in the following table, closely adapted from Deeper into Diving by Lippman and Mitchell:

Causes
The cause of narcosis is related to the increased solubility of gases in body tissues, as a result of the elevated pressures at depth (Henrys law). Modern theories have suggested that inert gases dissolving in the lipid bilayer of cell membranes cause narcosis. More recently, researchers have been looking at neurotransmitter receptor protein mechanisms as a possible cause of narcosis. The breathing gas mix entering the divers lungs will have the same pressure as the surrounding water, known as the ambient pressure. After any change of depth, the pressure of gases in the blood passing through the brain catches up with ambient pressure within a minute or two, which results in a delayed narcotic effect after descending to a new depth. Rapid compression potentiates narcosis owing to carbon dioxide retention.A divers cognition may be affected on dives as shallow as 10 m (33 ft), but the changes are not usually noticeable.