I would like to point you to a great article on the topic of meditation-induced dissociation.
Like any other practice, meditation is not suitable for everyone. There are no solutions that fit every human being, and that includes meditation. However, this mental training, while beneficial for many people, is often portrayed as a tool that serves all as an ultimate spiritual or self-development practice. Sometimes, one can have an impression that it is a universal solution for the majority of mental health problems or productivity issues. This is definitely not true, and many people get actually more anxious or frustrated while trying to master this method. Additionally, long-term engagement with meditation or intense retreats, like 10-day Vipassana retreat may lead to dissociation and persisting mental distress. There is no known scientific explanation for this process, but an experienced teacher should be aware of these problems and able to guide you out of the side-effects of this practice. With the current democratisation of many spiritual traditions, these undesired outcomes will be more common, and we need to start educating the public on how to prevent them.
My speculation for meditation induced depersonalization is that some people who start the practice are already dissociated in a degree that is unnoticeable for them on an everyday basis. Many people struggle with being in the present moment and being connected to the external world. While the majority of the meditation practitioners use this method to counterfeit these problems and be more grounded in the now and have more meaningful connections with others and environment, for some this might be a method of re-traumatisation and amplification of disconnection.
Most likely whether you will benefit or have unwanted outcomes of meditation depends on what kind of coping mechanisms you utilised in the past and which of them became your unconscious trait. People who had experienced a powerful “freeze” response in the past, most likely in the childhood, are more prone to be dissociated as a consequence of meditation.
The “freeze” response is one of the coping mechanisms (the other ones are “fight” and “flight”) that shuts down your sensory input in case of a stressful situation that your brain perceives as hopeless to deal with. It is a protection of your nervous system from override and body damage. While this coping strategy is usually a reaction to some traumatic event, many people have been also using this defence mechanism either consciously or unconsciously in response to other dangers perceived as life-threatening or leading to the nervous system overwhelm such as home conflicts, emotional abuse or neglect.
The human body has natural ways of leaving “freeze” response in the form of trauma discharge. This can be manifested in many ways – the most common is trembling, vomiting or intense crying. These behaviours reset your nervous system back to normal after the “freeze”. In our culture, the majority of people suppress these reactions. If these trauma releasing actions are inhibited and not initiated after the “freeze”, the trauma is stored in the nervous system memory and carried through the life until it is discharged. When this storing happens we develop Post Traumatic Stress Disorder (PTSD). It is likely then that PTSD is not caused by the event per se but by lack of behaviour that would release the nervous system imbalance caused by the “freeze” response.
Meditation can decrease the activity of the default mode network which is one of the control systems of your brain. This loss of control might be unconsciously perceived as an anxiety-provoking event which leads to a state that resembles the “freeze” response. Resulting temporary body disconnection and ego dissolution is the ultimate goal of the meditative experience. For those who had “freeze” response activated in the past, and were not able to release it, this might be re-traumatising because the experience is characterised by similar body disconnection.
If such re-traumatisation happens the effect stacks on already imbalanced nervous system leading to increased dissociation which eventually might become so severe that it begins to be perceived consciously. When the person starts to be aware of being in this imbalanced mental state, there is a high chance of fixation on the problem and consequent increase in anxiety that snowballs the magnitude of dissociation into full-blown depression. It seems like the sufferer is stuck in the “freeze” response and cannot get out.
Sometimes this can be a more controlled process - a result of an intention that was formed due to a lack of understanding of human psychology and practising meditation without the support of the teacher or more experienced peer. Some people might perceive the initial depersonalization or dissociation signals as positive and desired outcome of meditation, and delve deeper into the disconnected state because they think it takes them higher in the spiritual realms.
If you have prolonged periods of sober derealisation or feelings of being “spaced out” or cases of anxiety induced immobilisation, you should be careful with your meditation practice and any other activities that disinhibit your brain control centres such as psychedelics or trance-inducing activities. You might be more prone to dissociation and can eventually end up being depersonalised for a longer period. If you do not want to resign from meditation practice and believe that it can help you heal and connect find an experienced teacher that knows how to deal with the shadow side of this method. Additionally, set your intention to be more grounded and focus on finding reasons for the inability to fully connect and look for solutions to enable you to be more socially engaged. You can combine different healing techniques to support such an intention. For example, somatic and movement therapies are currently perceived as very effective modes of getting people out of “freeze” response and guiding towards joyful social life.