Seasonal changes in mood, energy, sleep or appetite can have different explanations. An appropriately qualified clinician can consider a person's symptoms, history, physical health, circumstances and any potential seasonal pattern rather than assuming a diagnosis from general information. Light therapy, CBT based therapy, medication review and other support may be considered in some circumstances. The relevant approach, timing, potential risks and outcomes vary by person and should be discussed individually. Light therapy is not appropriate to assume as a self directed option without considering health history and relevant clinical advice. Understanding a possible seasonal pattern Winter changes in mood, energy, sleep or appetite do not automatically establish seasonal affective disorder. An assessment can consider whether changes recur, how they affect daily life, whether there are other explanations and whether symptoms are consistent with depression, anxiety, physical health changes, medication effects, sleep difficulties or current pressures. A guide cannot diagnose a seasonal pattern or predict how it will develop. Considering support safely Light therapy, CBT based therapy, medication review and practical support are different options with different considerations. A regulated light device, timing and health history may matter for light therapy. Medication questions, including whether to begin, stop or change treatment, belong with an appropriate prescriber. CBT based therapy may explore changes in activity, routine, withdrawal, worry or low mood where clinically appropriate, but it is not a substitute for medical or specialist care. Medical and urgent safety boundaries New, severe or concerning physical symptoms, marked changes in sleep, appetite or energy, possible manic symptoms, medication effects or a sudden deterioration should be discussed with an appropriate medical professional rather than attributed automatically to a seasonal pattern. If you cannot keep yourself safe, have thoughts of harming yourself, experience psychosis, severe agitation, confusion or a sudden marked change in mental state, seek urgent help. In immediate danger, call 999 or attend A&E. Frequently asked questions Can I diagnose SAD from winter symptoms? No. A seasonal pattern needs individual assessment and may have more than one possible explanation. Is light therapy a self directed treatment plan? No. Its suitability and risks should be considered with relevant clinical advice. Related information is available at https://lyceumclinic.co.uk/therapy/depression/, https://lyceumclinic.co.uk/guides/depression in west london/, https://lyceumclinic.co.uk/guides/cbt for depression evidence/ and https://lyceumclinic.co.uk/approach/behavioural activation/. The Lyceum Clinic provides CBT based therapy for depression related concerns where clinically appropriate. Enquire directly about current arrangements, availability and whether a medical review, CBT based therapy or another source of support may be the more relevant next step.