When My Mood Changes in an Instant

Autism, stress, and emotional regulation

Other people may experience it as a sudden change. One moment, the conversation is calm and friendly. The next, there is a sharp comment, irritation, or an outburst that seems entirely out of proportion to what has just happened. The atmosphere can change within seconds.

“Your mood changes so quickly,” someone may say.

It is understandable that it looks that way from the outside. I experience this relatively often myself. I may be in a good mood, taking part in a conversation and feeling that everything is going well. Then a motorcycle passes with a piercing roar. An aeroplane flies low over the house. Someone interrupts the conversation or says something unexpected. Suddenly, my answers become shorter, my voice sharper, and my comment more irritated than the situation appears to justify.

To the other person, the change may seem inexplicable. It can also be difficult for me to understand until I later look back at what happened.

In everyday language, this is often described as a mood swing. In the professional literature, the term emotional regulation is frequently used. It refers to our ability to notice, understand, and regulate our emotions so that our response is reasonably suited to the situation. Everyone needs this capacity. For some people with an autism spectrum condition, ASC, however, emotional regulation may become particularly difficult when several sources of strain occur at the same time.

This does not mean that everyone with ASC responds in the same way. Nor does it mean that every irritated response or period of low mood can be explained by autism. In my case, however, there appears to be a clear connection between stress, intense sounds, unpredictability, and rapid emotional reactions.

This essay is an attempt to understand that connection. Not as an excuse, but as an explanation.

The reaction is sudden, but the strain has often been building

Perhaps the most important thing to understand is that the reaction may occur suddenly, even though the strain itself has not arisen suddenly.

From the outside, people usually see only the final event. They hear the sharp comment. They see the facial expression change. They notice that the good atmosphere has disappeared. It may therefore appear that a minor event has caused a major reaction.

But the final event is not necessarily the whole explanation. It may be the last drop in a glass that was already almost full.

Before the motorcycle passed, there may have been several hours of concentration, social activity, or noise. Before the conversation took an unexpected turn, I may already have used considerable energy trying to follow it, interpret the words, hear correctly, and understand what the other person meant. Before the angry comment was made, my body may have been in a state of tension that I had not yet consciously recognised.

It is not the motorcycle alone that creates the reaction. It is the accumulated burden.

This is what makes these reactions difficult to explain. Other people see the moment. I have to try to understand its history.

A brain that processes the world differently

Autism, or autism spectrum condition, is an inborn neurodevelopmental condition. This means that, from early life, the brain develops and processes information somewhat differently from the way it does in the majority of people.

This does not mean that the whole brain functions less effectively. People with ASC may have considerable strengths in areas such as memory, concentration, pattern recognition, attention to detail, and the ability to become deeply absorbed in a subject. At the same time, the brain may use more energy sorting sensory information, shifting attention, managing unpredictability, and regulating emotional arousal.

The word “spectrum” is important. There is no single autistic brain, nor is there one pattern of response that applies to everyone. The differences between autistic people are substantial. I cannot therefore assume that what happens in me happens in the same way in every other person with ASC.

Nevertheless, some neurological explanations may help us understand why stress, sound, and unpredictability can sometimes have such powerful effects.

The brain is constantly receiving enormous amounts of information. Sounds, visual impressions, smells, physical sensations, words, facial expressions, and expectations all arrive at the same time. Most of this information must be sorted, reduced, or prioritised. Otherwise, we would quickly become overwhelmed.

For many people, this sorting happens almost automatically. A motorcycle in the distance is registered, but the brain quickly decides that the sound is not important. It is moved into the background so that the conversation can remain in the foreground.

In my brain, this filtering does not always seem to happen as effectively. The sound does not remain in the background. It pushes itself forward and demands attention. What is a brief noise to another person can feel to me like an assault on my concentration and sense of calm.

This does not necessarily mean that my ears physically hear the sound as louder. The difference may lie in how the brain processes, sorts, and reacts to what is heard. A sound may be given greater significance by the nervous system than the situation itself appears to warrant.

When sound enters the body

For many people, a motorcycle is simply a motorcycle. The sound arrives, and then it disappears. For me, the sound can be experienced as more than ordinary background noise. It can feel piercing, intrusive, and physically uncomfortable.

The same applies to aircraft noise, sudden machinery, hammering, loud voices, or other sounds that occur without warning. The problem is not always the volume alone. It is also the nature of the sound and the fact that I cannot control when it will occur.

The brain contains systems that rapidly assess whether something is important, threatening, or unexpected. The amygdala is often mentioned in this context. It is not simply a “fear centre”, but part of larger networks that help identify what requires attention and readiness.

When a sudden motorcycle, a low-flying aeroplane, or another powerful sound is registered as especially significant, the body’s alarm system may be activated. The heart rate may increase. Muscles tighten. Attention narrows. The brain moves from open conversation into a state of alert.

This reaction occurs quickly, often before conscious thought has had time to interpret the situation.

An unexpected sound can therefore interrupt a thought, break concentration, and create an immediate state of physical alarm. Patience becomes more limited. Something said in the conversation just before or after the sound may be met with a sharpness that is actually directed at the total burden, rather than at the person.

The other person does not necessarily know this. They hear only the comment and may quite reasonably experience it as unpleasant.

It is therefore important to explain the connection without pretending that its effect on other people does not matter.

When the regulating thought arrives too late

While the brain registers danger, significance, and discomfort, other parts of the brain are meant to help us assess our response. Areas in the front of the brain contribute, among other things, to planning, flexibility, impulse control, and emotional regulation.

These systems help us pause and think:

“It is only a motorcycle.”

“Perhaps that remark was not intended as criticism.”

“I do not need to answer immediately.”

But this regulation requires capacity. When I am already tired, stressed, or occupied with understanding a demanding conversation, the brain may have less capacity available to moderate the initial response.

It is not necessarily that I do not know how I ought to respond. The problem may be that the regulating thought arrives a few seconds too late.

First comes the sound or the surprise. Then comes the body’s state of alert. Next comes the sharp comment. Only afterwards does reflection arrive:

“That was not how I wanted to respond.”

When this happens, it may look as though the emotion appeared from nowhere. Neurologically, however, it may be understood as the brain registering the burden more quickly than conscious regulation could respond to it.

When the brain has to manage too much at once

Emotional regulation does not take place in one single part of the brain. It results from cooperation between several networks. Some register sensory input. Some assess importance and danger. Some monitor the condition of the body. Others help us think, adapt, and restrain an immediate response.

When these systems cooperate effectively, I can both notice my irritation and choose what I do with it.

When the burden becomes too great, this cooperation may become less effective. The brain may have to manage the intense sound, understand the words being spoken, interpret the other person’s intention, find an appropriate answer, and regulate the body’s agitation at the same time. All of this happens within seconds.

A kind of neurological queue can then develop.

Several tasks demand attention at once, but capacity is limited. The brain prioritises what feels most intrusive. The loud sound and physical alarm may then take priority over reflection, nuance, and politeness.

It is not a conscious decision to become angry. But neither is it an action without consequences.

The autonomic nervous system

The autonomic nervous system regulates many of the body’s responses without our consciously deciding them. It influences the heart rate, breathing, muscular tension, and the body’s general state of readiness.

When a situation is perceived as demanding, the body’s mobilisation system is activated. We become prepared to act, defend ourselves, or escape. When the situation again feels safe, the body should gradually return to a calmer state.

For some people with ASC, the transition from calm to intense alertness may occur rapidly, while the return to calm can take much longer. A sound lasting only a few seconds may therefore continue to affect the body long after it has disappeared.

This may explain why I do not necessarily become calm as soon as the motorcycle has passed. My body is still in a state of alert. If the conversation continues as though nothing has happened, I may respond to the next question with an irritation that was actually triggered by the preceding sensory experience.

To the other person, the response seems illogical. The question was friendly.

But my body is not responding only to the question. It is also responding to the sound, the surprise, and the activation that is still present in my nervous system.

The unexpected demands more than other people can see

Unpredictability can play just as important a role as sound. A conversation does not always follow the direction one expects. The other person may change the subject, make a remark I do not understand, ask an unexpected question, or interpret something I have said differently from the way I intended it.

Most people can, of course, become surprised or uncertain in such situations. For a person with ASC, however, rapid changes may require additional mental adjustment.

The brain is constantly trying to predict what will happen next. It uses previous experience to form expectations about the next sound, the next sentence, and the next event. This makes the world more manageable.

When what happens broadly matches what was expected, little adjustment is required. When something unexpected happens, the brain has to update its understanding.

For people with ASC, this updating may require more effort. A sudden change in a conversation is therefore not simply a new topic. It may require the entire internal understanding of the situation to be reorganised.

What are we talking about now? Why did the conversation change direction? Have I misunderstood something? Is a different response expected from me? Is the other person irritated, joking, or serious?

When this occurs at the same time as noise or stress, the brain may receive too many updates at once. Flexibility becomes more difficult, and my response may become more categorical or sharper than I intend.

This does not mean that I lack interest in the other person. Nor does it mean that I do not want dialogue. On the contrary, I may care deeply about understanding correctly. But the very desire to understand can make the situation demanding when the conversation suddenly moves in another direction.

What is actually confusion, overload, or a need for time may then be expressed as irritation.

When the body knows before I do

Emotional regulation begins with noticing what one is feeling. This sounds simple, but it is not always so.

I may register the sound of the motorcycle while failing to notice what the sound is doing to my body. I may sense that a conversation is becoming more demanding without understanding that my stress level is becoming too high. I may believe that I am still in control until the sharp comment has already been made.

To regulate an emotion, I first have to register and interpret signals from the body: an increased heart rate, a clenched jaw, unease in the stomach, faster breathing, or tension in the shoulders. This perception of the body’s internal condition is often called interoception.

In people with ASC, the ability to register and interpret these bodily signals may be different. Some people experience them very intensely. Others notice them late or have difficulty understanding what they mean. A person may know that something is happening in the body without knowing whether it is anger, fear, overload, hunger, or exhaustion.

I may therefore be moving towards a strong reaction without realising how close I am to my limit.

The body knows before I do.

By the time I recognise the feeling, it may already have become a comment, a raised voice, or an urgent desire to end the conversation.

This may be what makes the response seem so sudden, even to me. The transition does not necessarily begin at the moment when the comment is made. It may have been developing in the body for some time without being clearly available to conscious awareness.

Afterwards, I can often understand more. I can see that I was tired. I can see that the sound affected me more strongly than I first realised. I can see that the conversation became unpredictable at a time when I already had little energy left.

But this understanding comes too late to prevent the reaction.

An explanation is not an excuse

It is important for me to emphasise that this essay is not an attempt to excuse hurtful or unreasonable comments.

A diagnosis does not release anyone from responsibility for how they treat other people. A person who is met with an angry comment may feel hurt, confused, or unsafe, regardless of what lay behind the response. That experience must be taken seriously.

But responsibility is not strengthened by refusing to understand the causes. Quite the opposite. If I am to take responsibility, I must also try to understand what is happening within me.

An explanation does not say:

“This is simply how I am, so you must tolerate it.”

An explanation says:

“This is something that happens to me under particular forms of strain. I must learn to recognise it, and the people close to me may understand the situation more easily when they know what is happening.”

There is an important difference.

Explaining the response may make it possible to prevent it. It can open conversations about pauses, noise, stress, expectations, and the need for additional time. It may also make it easier to repair the situation when something has gone wrong.

I can say:

“What I said was unnecessarily sharp. I was overloaded, but it was not your fault.”

Such a sentence contains both explanation and responsibility.

Responsibility must begin before the reaction

I have a responsibility to try to recognise the strain earlier. I can withdraw before the glass becomes full. I can use hearing protection or close a window when the noise becomes too intense. I can ask for a few seconds’ pause in a conversation. I can say that I do not fully understand what has just happened instead of responding with irritation.

I can also try to speak before the situation becomes difficult:

“That was a lot of noise.”

“I need a little time to think.”

“That took me by surprise.”

“Could we pause for a moment?”

Such sentences may appear simple, but they require me to recognise the reaction in time.

Knowledge about the brain does not release me from responsibility. Instead, it shows where responsibility must begin: not only after the angry comment has been made, but earlier, when the body becomes tense, sounds become intrusive, and the capacity to adapt begins to weaken.

At the same time, the people around me also have an opportunity to help. Not by walking on eggshells or accepting everything, but by understanding that sudden sounds, stress, and unexpected changes may affect me more strongly than is visible from the outside.

Understanding does not mean that the other person must always adapt. But it may mean that both people become somewhat less concerned with blame and more concerned with what actually happened.

It may not be the mood that changes

When I think about it more carefully, I am not certain that “mood swing” is always the most precise term.

My mood can, of course, change. But it may not always be a transition from happiness to anger in the ordinary sense. It may be a rapid transition from coping to overload.

As long as I can manage the sounds, the conversation, the expectations, and my own bodily reactions, I appear calm. When that capacity is suddenly exceeded, the reaction becomes visible.

The other person experiences a mood swing. I experience that something became too much.

Both experiences can be true.

The problem arises when only one of these perspectives is allowed to exist. If the response is described only as bad temper, it may appear arbitrary, unreasonable, or personally directed. If it is explained only as overload, we may overlook the way it actually affects other people.

We therefore need both perspectives: how the reaction is experienced by the other person, and how it arises within me.

Not a damaged brain, but a differently burdened brain

It is easy to describe all of this in terms of deficits. Poor filtering. Weak regulation. Lack of flexibility. But such language is too simple.

The same brain that can be overwhelmed by sound may also notice details that other people miss. The same brain that needs time to adjust may persist with a problem and examine it thoroughly. The same sensitivity that makes certain sensory experiences painful may also make other experiences intense, rich, and meaningful.

The neurological perspective should therefore not reduce a person to a collection of differences or deficiencies in the brain.

It should help us understand that the response has a bodily and neurological dimension. When I become sharp after a sudden sound or an unexpected change, it is not merely a matter of attitude or willpower. The brain and nervous system have already begun to respond.

Even so, the response is mine. I must try to take responsibility for it.

This may be the difficult balance: understanding that the response is not always intentional, without pretending that it is therefore without significance.

Learning to recognise my own pattern

I do not believe the goal can be to remove every strong reaction. Human beings are not machines. We become tired, frustrated, afraid, and angry. But it should be possible to understand one’s own pattern more clearly.

For me, this means understanding combinations. Stress on its own may be manageable. A motorcycle on its own may be unpleasant but brief. An unexpected remark on its own can often be met with curiosity.

But when stress, sound, and unpredictability occur together, the space available for regulation becomes smaller. The sharp comment may then arrive before reflection.

This knowledge does not give me complete control. But it gives me more possibilities. I can plan for more recovery time. I can be especially attentive on days when the burden is already high. I can try to avoid demanding conversations when I am close to my limit. I can explain to those closest to me that it may sometimes be better to give me a moment rather than continue the discussion while my body is still in a state of alarm.

I can also learn to recognise the early signs. Perhaps I clench my jaw. Perhaps my heart rate increases. Perhaps I become less talkative. Perhaps I begin to experience ordinary questions as demands. Perhaps I feel an intense desire for the conversation to end.

Such signals are not insignificant. They are the body’s way of communicating that the capacity for regulation is beginning to weaken.

And when I nevertheless react too strongly, I can return and try to make things right.

When the body needs a restart

After such an episode, it is not always enough simply to decide to calm down. The body must be given time to do so.

For me, this often means rest. I think of it as a “restart”, to borrow a term from computing. When a computer has been given too many tasks at once and no longer functions as it should, it may have to be stopped and restarted. Something similar can happen to me when stress, sound, and unpredictability have become too much.

I need to withdraw from sensory input. A quiet, dark room can help. Meditation can also help. I do not necessarily need to think through what happened immediately. First, the body must receive the message that the danger has passed, that no new demands are coming, and that it no longer needs to remain on alert.

Sometimes five minutes are enough. At other times, it may take several hours. After more intense episodes, it can take one or two days before I feel fully restored.

The exhaustion can be overwhelming. My body may feel as though it has run a marathon, even though I may only have been sitting in a room taking part in a conversation. It can be difficult for other people to understand how physical such an overload feels. It is not only the mind that is tired. The whole body can feel heavy, empty, and drained of energy.

Sleep often helps. I may sleep for several hours and wake with the feeling that the system has been restarted. The tension has disappeared. The body is calmer. What felt overwhelming a few hours earlier may have lost much of its power.

Sometimes I also find that the episode itself has become unclear. I may remember that something happened, but not necessarily what was said or what led to the rupture. I may understand that I have hurt someone and apologise, while still being unable to remember the situation in the same way as the other person.

At such times, I need the event to be explained to me calmly.

Not as an accusation and not as the beginning of a new confrontation, but as help in understanding:

“This is what happened.”

“This is what you said.”

“This is how I experienced it.”

Such an explanation enables me to take responsibility even when my own memory of the episode is incomplete. I need to understand how my reaction affected the other person. At the same time, it helps when the event is placed in context:

“It became too much for you.”

“It was good that you withdrew and found quietness and calm.”

Such words do not dismiss what happened. They do not suggest that the other person was not hurt. But they acknowledge that withdrawing was an attempt to prevent the situation from becoming even more difficult.

From the outside, withdrawing may look like rejection. For me, it may be the most responsible action I am capable of taking at that moment. I do not necessarily leave because I do not care about the other person. I leave because I no longer have the capacity to remain present in a constructive way.

The silence is not a punishment. It is treatment.

The darkness is not an escape from reality. It is temporary protection from further sensory input.

Sleep is not indifference. It is the body’s way of recovering.

Meditation helps me gradually return to my breathing, my body, and the present moment. It does not require me to explain or analyse everything immediately. First, it helps me rediscover an inner calm. Afterwards, the conversation may be able to continue.

It is important that rest does not become the final conclusion to the event. When my body is calm again, I must be able to return to the person I have hurt. I must listen to how the situation was experienced, even when I do not remember everything. I must be able to apologise without becoming defensive.

But this conversation should take place when the nervous system once again has the capacity for it.

If we try to resolve everything while the body is still in a state of alarm, the words may only increase the burden. What was intended as clarification may become a new conflict. The pause is therefore not necessarily a breakdown in the conversation. It may be the condition that allows the conversation to continue more constructively later.

A good restart therefore involves two movements.

The first leads away from the noise, the demands, and the conversation—into darkness, silence, meditation, or sleep.

The second leads back to the other person.

First, the body must find calm. Then, the relationship must receive attention.

Both are necessary.

Being understood as a whole person

It can be difficult to live with reactions that one does not always manage to control in time. It can also be difficult to live close to someone who suddenly becomes sharp or irritated.

We therefore need language that neither condemns nor excuses.

“Mood swings” describes how the reaction appears.

“Difficulties with emotional regulation” describes something of what may be taking place.

“Sensory overload” points towards sounds and other forms of sensory input.

“Neurological activation” says something about the state of readiness in the brain and body.

“Unpredictability” points towards the need for adjustment.

None of these terms contains the whole experience. Together, however, they may help us understand that a sudden reaction is rarely the whole story.

I do not want ASC to become an explanation for everything I do. Nor do I want to be understood as a person without responsibility. But I do want what happens to be seen in context.

When my voice becomes sharp, it does not necessarily mean that my relationship with the other person has suddenly changed. It does not mean that the good conversation was false. It may mean that the combined burden of stress, sound, and unpredictability became greater than my capacity for regulation at that particular moment.

That does not make the angry comment right. But it makes it possible to understand.

And what we understand, we also have a better opportunity to take responsibility for.

We need a language that neither condemns nor excuses.

Author’s note

This essay is based on my own experiences of autism spectrum condition, stress, sensory overload, and emotional regulation. Its purpose is not to excuse hurtful reactions, but to explain how they may arise, what may help afterwards, and why understanding and responsibility must go hand in hand. Professional perspectives on the brain’s processing of sensory input and emotions have been presented in accessible language. OpenAI/ChatGPT was used as a conversational and writing partner in the development of the text.