I believe that it is crucial to think of Mental Health/Psychiatric Care as a separate issue from enlightenment.
It is also true that basic buddhist strategies, like mindfulness and right speech and the like have been shown to help correct the neurotransmitter imbalance that leads to mental health disorders.
In some tradtions enlightenment is deliverance from dukkha - which is where the word 'suffering' is translated from and I think your question takes root.
wikipedia:
Within the Buddhist tradition, dukkha is commonly explained according to three different patterns or categories. In the first category, dukkha includes the obvious physical suffering or pain associated with giving birth, growing old, physical illness and the process of dying. These outer discomforts are referred to as the dukkha of ordinary suffering (dukkha-dukkha). In a second category, dukkha also includes the anxiety or stress of trying to hold onto things that are constantly changing; these inner anxieties are called the dukkha produced by change (vipariṇāma-dukkha). The third pattern or category of dukkha refers to a basic unsatisfactoriness pervading all forms of life because all forms of life are impermanent and constantly changing. On this level, the term indicates a lack of satisfaction, a sense that things never measure up to our expectations or standards. This subtle dissatisfaction is referred to as the dukkha of conditioned states (saṃkhāra-dukkha).
Buddhism is not a self-help system for sad people. It is a system of looking at experience. One of the most common egoic and twisted pieces of advice I see is that, 'If you meditate, you wil be happier"... which is a ridiculous twisting of the original teachings.