Deviation from ideal mental health was proposed by Jahoda (1958).
Instead of focusing on abnormality, Jahoda looked at what would comprise the ideal mental state of an individual.
The criteria for ideal mental health:
being able to self-actualise
having an accurate perception of ourselves
not being distressed
being able to maintain normal levels of motivation to carry out day-to-day tasks
displaying high self-esteem
The main issue with deviation from ideal mental health is that Jahoda may have had an unrealistic expectation of ideal mental health, with the vast majority of people being unable to acquire, let alone maintain, all of the criteria listed.
Deviation from ideal mental health may be considered a very limited method of diagnosing mental health disorders as it means that the majority of the population would be considered abnormal, even if they have only missed a single criteria.
Deviation from ideal mental health suffers from cultural relativism.
On the other hand, self-actualisation may be a more popular concept in individualist cultures (e.g. the UK), where personal achievement is celebrated and the needs of the individual are greater than the needs of the group.
Deviation from ideal mental health would only be accepted as a definition for abnormality in some (individualist) cultures.